CHAPTER 4
The Solution
Forget calories.
Focus on quality.
Let your body do the rest.
In chapter 3, we saw why conventional diets rarely work. Excessive weight gain occurs when fat cells suck up and store too many calories, leaving too few for the rest of the body. Low-fat, low-calorie diets don’t solve this basic problem, and can make matters worse. Faced with calorie deprivation, the body goes into starvation mode and fights back. Hunger and food cravings rise and metabolism slows—the perfect recipe for weight regain and disordered eating habits.
A more effective approach is to reprogram your fat cells to lose weight, by eating in a way that lowers insulin levels and reduces inflammation. When this happens, fat cells calm down and release their excess calorie stores. As the body begins to enjoy better access to fuel, metabolism runs better, hunger and cravings subside, and weight loss occurs naturally. It’s diet without deprivation.
In this chapter, we’ll take a deeper look into the components of this approach. But feel free to jump right to the Always Hungry Solution in part 2 if you’ve had enough science for now.
THE MAJOR NUTRIENTS—CARBOHYDRATE, PROTEIN, AND FAT
Mini Quiz #1:
What is the minimum amount of carbohydrate required for long-term survival?
(Answer here.)
What major nutrients does the body require to run effectively? The answer may be surprising. The body needs a few ounces of protein from the diet on a daily basis to repair tissues and to run the biochemical reactions that make up our metabolism. It needs a fraction of an ounce of fat (specifically, the essential omega-3 and omega-6 fatty acids) for cell membranes and cell-to-cell communication. Beyond these minimal amounts, our nutritional requirements can be satisfied with almost any combination of the major nutrients. The one nutrient we don’t need at all is carbohydrate.
In the absence of carbohydrate from the diet, the body can produce all the fuel needed by the brain from protein and fat alone. We have enormous biological flexibility in which major nutrients to eat. That’s why Inuits in the Arctic could survive on traditional diets consisting almost exclusively of sea and land animals. In contrast, many hunter-gatherers living at less extreme latitudes eat plant-based diets, with meat as a supplement.1
Today, we also have a virtually unlimited choice of foods, leading to a key question: What is the optimal proportion of carbohydrate, protein, and fat for weight control and chronic disease prevention? More than any other, this question distinguishes most popular weight loss diets, ranging from the very-high-carbohydrate Ornish diet to the ultra-low-carbohydrate ketogenic diet (see A Comparison of Popular Weight Loss Diets graph here).
A Comparison of Popular Weight Loss Diets
Phase 1 of the program is located to the right side of the figure, near—but not as stringent as—the Atkins diet. Phase 2 resembles in nutrient composition the South Beach, Zone, and Paleo diets. Phase 3 moves closer to a typical Mediterranean diet. This final phase resides squarely in the middle of the figure, one indication that it is among the least restrictive of all options.
We cut total carbohydrate in half for the two weeks of Phase 1, from about 50 percent typically consumed in the United States to 25 percent of total calories (100 to 150 grams, based on energy requirements). Decreasing carbohydrate is the quickest and easiest way to lower insulin levels and jump-start weight loss. In Phases 2 and 3, total carbohydrate increases moderately, to about 40 percent of total calories. The type of carbohydrate also matters critically in all phases, which we’ll consider in the next section.
Beyond basic biological requirements, protein plays an important role in weight control, in part by triggering release of the hormone glucagon.2 Glucagon, also made in the pancreas, performs the opposite functions of insulin, by pulling fuels out of storage and helping to prevent the calorie crash a few hours after eating. In this way, glucagon and insulin have complementary effects on metabolism. Protein in the right amounts counterbalances carbohydrate.
But before digging in to that 20-ounce steak, keep in mind that the biological range for dietary protein is substantially smaller than for the other major nutrients. Intakes above 35 to 40 percent of total calories exceed the liver’s capacity to process amino acids (the building blocks of protein), resulting in buildup of ammonia to toxic levels.3 People naturally tend to avoid getting anywhere near that upper limit. On this program, you will consume 100 to 140 grams of protein a day, which works out to approximately 25 percent of daily calorie intake in Phases 1 and 2. Protein proportion then decreases to 20 percent in Phase 3, as body weight and calorie intake stabilize.
The remainder of calories comes from fat, with an emphasis on the types found in olive oil and nuts. As we saw in chapter 3, these fats are among the healthiest components of the diet. They slow digestion rate, help you feel full for hours after eating, and powerfully lower risk for heart disease. They also make for delicious recipes—no Spartan low-fat dressing, sauces, or spreads here! In Phase 1, fat comprises 50 percent of total calories, displacing all processed carbohydrate. This high amount will lower insulin secretion, help soothe fat cells, and get metabolism back on track. Fat proportion decreases to 40 percent by Phase 3, approximately equal to carbohydrate (based on individual tolerance), providing flexibility in food choices.
(Mini Quiz #1 Answer: 0)
LOW CARBOHYDRATE OR SLOW CARBOHYDRATE?
Mini Quiz #2:
Which of the following raises blood glucose and insulin the most after consumption, calorie for calorie?
1. white potato (baked)
2. ice cream
3. pure table sugar
(Answer here.)
People with major metabolic problems, like severe insulin resistance or type 2 diabetes, may benefit from long-term carbohydrate restriction—to 25 percent of daily calories as in Phase 1 or sometimes even lower. Preliminary studies report that some individuals experience remarkable improvements in health by eliminating virtually all carbohydrates on a ketogenic diet.4 Without carbohydrate, insulin secretion plummets and the body switches from the sugar glucose to ketones (chemicals derived directly from fat) as its main fuel. Some scientists consider ketones to be a sort of “superfuel” that might enhance mental performance, physical endurance, and general well-being, and possibly slow down the aging process.5 However, ketogenic and other very-low-carbohydrate diets can be quite challenging to follow over the long term, and the possibility of adverse effects has not been ruled out. Usually, such severe restriction isn’t necessary.
Just as calories differ according to how they affect the body, so too do carbohydrates. All carbohydrates break down into sugar, but the rate at which this occurs in the digestive tract varies tremendously from food to food. This difference forms the basis for the glycemic index (GI).6
The GI ranks carbohydrate-containing foods according to how they affect blood glucose, from 0 (no affect at all) to 100 (equal to glucose). Gram for gram, most starchy foods raise blood glucose to very high levels and therefore have high GI values. In fact, highly processed grain products—like white bread, white rice, and prepared breakfast cereals—and the modern white potato digest so quickly that their GI ratings are even greater than table sugar (sucrose). So for breakfast, you could have a bowl of cornflakes with no added sugar, or a bowl of sugar with no added cornflakes. They would taste different but, below the neck, act more or less the same. Minimally processed grains, nonstarchy vegetables, whole fruits, beans, nuts, and unsweetened dairy products have more gentle effects on blood glucose and, consequently, lower GI values.
A related concept is the glycemic load (GL), which accounts for the different carbohydrate content of foods as typically consumed (see the Glycemic Load of Carbohydrate-Containing Foods chart in Appendix A, here).7 Watermelon has a high GI, but relatively little carbohydrate in a standard serving, producing a moderate GL. In contrast, white potato has a high GI and lots of carbohydrate in a serving, producing a high GL. If this sounds a bit complicated, think of GI as describing how foods rank in a laboratory setting, whereas GL as applying more directly to a real-life setting. Research has shown that the GL reliably predicts, to within about 90 percent, how blood glucose will change after an actual meal—much better than simply counting carbohydrates as people with diabetes have been taught to do.
Hundreds of studies have examined the effects of GI and GL on body weight and numerous other health outcomes.8 In the largest clinical trial of its kind ever done,9 773 adults from eight European countries who had achieved at least 8 percent weight loss on a standard diet were randomly assigned to diets varying in GI and protein. After six months, the group on the low-GI/high-protein diet (which would be lowest in GL) showed complete weight loss maintenance, with no weight regain at all—an impressive accomplishment for a diet study. Participants on the high-GI/low-protein diet (highest in GL) regained the most weight, and those on the other two combinations—low-GI/low-protein and high-GI/high-protein (both medium in GL)—regained an intermediate amount of weight. These data resemble a dose-response curve, common in drug studies but rarely seen in nutrition. The findings are clear: Each stepwise decrease in GL produced progressively better results.
Even controlling for body weight, high-GI and -GL diets are associated with chronic disease in observational studies. A major analysis, including all published data on the topic, found that people with high-GI diets had 20 percent increased risk for diabetes compared to those with low-GI diets.10 It stands to reason that the excessive rise and fall of blood glucose on a high-GI diet would put stress on the insulin-producing cells of the pancreas. If those cells are already struggling because of insulin resistance, chronic inflammation, or genetic risk factors, a high-GI diet could be the last straw.
High-GI and -GL diets are also strongly associated with risk for heart disease. In one study of about 75,000 women, a high-GL diet increased risk for coronary heart disease twofold over ten years.11 These results suggest that switching from a high-to a low-GL diet could cut heart disease risk in half—and that’s exactly what’s been seen in clinical trials of drugs like acarbose that act by slowing down digestion of carbohydrates in the gut.12 (Though unlike a low-GL diet, these drugs have side effects.)
In addition, high-GI and -GL diets have been linked to cancer (breast, endometrial, colorectal), stroke, gallbladder disease, fatty liver, and depression in observational analyses, but more research is needed on these relationships.13
Despite strong evidence favoring a low-GI diet, small or short-term studies do show some inconsistencies in outcomes, as is virtually always the case in nutrition research. Researchers from Boston and Baltimore gave 163 adults four diets varying in carbohydrate and GI, keeping calorie intake constant throughout the study. They reported that the low-GI diets produced no improvements in insulin sensitivity, lipids, or blood pressure after 3.5 to 5 weeks.14 However, as my colleagues and I recently argued, this study may simply not be long enough to see potentially important effects.15 For example, 316 adults in the United Kingdom were randomly assigned to three groups and provided varying amount of whole grains for sixteen weeks. Even though the duration of this study was more than three times longer than the Boston and Baltimore study, there were no effects on any of twenty-two cardiovascular disease risk factors, including body weight, lipids, and blood pressure.16 We wouldn’t abandon the recommendation to substitute whole grains for refined grains based on short-term studies. In any event, other clinical studies of low-GI diets have reported significant improvements in insulin resistance, chronic inflammation, and serum lipids, especially when calorie intake and body weight were allowed to fluctuate naturally.17
Compared to severely restricting carbohydrate as with the Atkins diet, the effects of a low-GI diet are less dramatic at first. But many people can’t remain on very-low-carbohydrate diets indefinitely. A low-GI diet may be more like the tortoise than the hare—it takes a bit longer, but gets you there in the end. Thus, switching from highly processed carbohydrates to low-GI alternatives can reduce body weight and lower risk for chronic disease without having to abandon a whole class of nutritious (and delicious) foods.
Another benefit of a minimally processed, low-GL diet may be fewer gastric bypass surgeries.18 Because whole foods tend to digest slowly, some of their nutrients travel down the full length of the small intestines, simulating powerful hormones that rev up metabolism and help us feel full (a feedback mechanism called the “ileal brake”). Highly processed industrial foods—epitomized by modern fast foods—digest in the first segments of the intestines, too quickly to trigger this built-in weight-regulating mechanism. Not surprisingly, fast-food consumption is strongly linked to obesity and type 2 diabetes.19 To deal with the consequences of too much highly processed foods (which comprise the majority of the American diet20), we’re increasingly resorting to weight loss surgery. The most common procedure of this type (called roux-en-Y gastric bypass) reroutes the gastrointestinal tract, so that even rapidly digestible food reaches farther down in the intestines. As a result, people experience intense feelings of satiety regardless of what they eat. From this perspective, we seem to have a choice—bypass the gastrointestinal tract or bypass the highly processed diet.
Whole, natural, slow-digesting foods provide the foundation for all phases of the program. In Phase 1, you’ll eliminate—for just two weeks—grain products, potatoes, and concentrated sugars (except for a small amount in very dark chocolate). Instead, carbohydrate will come from the lowest GL foods, including nonstarchy vegetables, non-tropical fruits, beans, and nuts. But rest assured that with three meals and two snacks a day of rich, satisfying foods, you won’t feel hungry or deprived, and your cravings will quickly subside. You might be surprised how easily you can do without all the processed carbohydrates!
In Phase 2, you’ll add back minimally processed grains, starchy vegetables (except white potato), tropical fruits like banana, and a touch of sugar. And in Phase 3, some of the more processed carbohydrates can be mindfully reintroduced, allowing for maximum flexibility based on individual tolerance. For people following a gluten-free diet, the Always Hungry Solution is easily adaptable, with whole-kernel alternatives to wheat and other gluten-containing grains.
(Mini Quiz #2 Answer: 1. white potato)
TYPES OF FAT
Mini Quiz #3:
Which is less healthy for your heart—white bread or butter?
(Answer here.)
For much of the last half century, fat was considered the least healthy of the three major nutrients, and saturated fat the worst possible type of fat.21 Saturated fats, such as those in butter and coconut, form a solid at room temperature. In contrast, monounsaturated fats (in olive oil and nuts) and polyunsaturated fats (in fatty fish, some nuts, and vegetable oils) are liquid at room temperature.
Saturated fat got a bad reputation in the 1960s with the observation that it raised LDL cholesterol, a risk factor for heart disease. Since then, national nutritional recommendations have consistently advised reducing saturated fat intake to very low levels. Largely for that reason, consumption of margarine made from partially hydrogenated vegetable oils (also known as trans fats) surged in the 1970s and 1980s. Solid at room temperature, trans fats became an attractive alternative to butter for health-conscious consumers. Unfortunately, these unnatural fats turned out to be far worse than saturated fat, becoming the closest thing to poison among additives in the food supply.22 Until recent efforts to ban their use, trans fats caused tens of thousands of deaths from cardiovascular disease each year in the United States.23
Recently, the pendulum has swung in the other direction, with some popular diet books lauding the nutritional benefits of saturated fat. Despite its negative effects on LDL cholesterol, saturated fat also raises heart-protective HDL cholesterol, leaving their ratio relatively unchanged. In contrast, high-GI carbohydrates lower HDL cholesterol and raise triglycerides, combined effects that appear to be worse for cardiovascular disease than saturated fat.24 Danish researchers confirmed this possibility in a study of about fifty thousand adults followed for twelve years. They found that exchanging saturated fat for high-GI carbohydrates was associated with a 33 percent increased risk for heart attack.25 Exchanging saturated fat with low-GI carbohydrates decreased risk, but that trade-off doesn’t typically occur. When people in Western countries eat less saturated fat, they tend to have more refined starch and sugar—not fruits, beans, or nuts.26
Indeed, two highly publicized reviews showed essentially no relationship between saturated fat consumption and cardiovascular disease in the general population.27 However, these analyses inevitably set the bar quite low. The average diet in the United States and other Western countries is loaded with highly processed foods and predisposes the entire population to cardiovascular disease and diabetes. For a dietary component not to increase risk beyond this already high level isn’t saying very much.
Many studies show that diets high in unsaturated fat rather than saturated fat reduce disease risk. In an analysis of randomized controlled trials involving about thirteen thousand participants, substitution of polyunsaturated fat for saturated fat decreased cardiovascular disease by 19 percent, with even larger effects seen in the longest interventions.28 Monounsaturated fats may provide similar benefits.29 Of particular concern, saturated fat may also cause chronic inflammation and insulin resistance, the underlying biological events linking obesity to chronic disease. After just one meal, saturated fat adversely affected markers of inflammation in the blood, blood vessel elasticity, and insulin action compared to unsaturated fat.30 In animal studies, a diet high in saturated fat has been shown to activate powerful inflammatory pathways, cause inflammation of the hypothalamus (the key brain region regulating hunger and metabolism), increase insulin levels, and alter fat cell activity.31
Two recent studies provide further evidence that, like carbohydrate, all fat calories are not alike. In one trial, thirty-nine adults of normal weight were overfed 750 calories a day with muffins containing either saturated fat (from palm oil) or polyunsaturated fat (sunflower oil). After seven weeks, both groups had gained about 3 pounds, as expected, but total body fat and liver fat were significantly greater in the saturated fat group, whereas lean body tissue was greater in the polyunsaturated fat group.32 In the other trial, thirty-four young adults received diets that were high in either saturated (palmitic) or monounsaturated (oleic) fat during two separate three-week periods. Otherwise, the diets were the same, and neither the participants nor the researchers knew which type of fat was given first. Remarkably, participants consuming the saturated fat diet had slower metabolic rate at rest, were spontaneously less physically active, and reported higher levels of anger and hostility.33 It’s not so surprising that the quality of the fat we eat can influence our metabolism, body composition, energy level, and even emotions when you consider the profound effects that chronic inflammation and insulin resistance have on the body and the brain.
Furthermore, not all saturated fats are alike. The saturated fats in dairy appear to be healthier than those in red meat.34 Shorter chain saturated fatty acids, such as the kind found in coconut, are metabolized quickly and don’t stick around long enough to cause much trouble. And to make matters even more complicated, the amount and type of carbohydrate in the diet influences how dietary fat affects blood lipids, with saturated fat and processed carbohydrate being an especially dangerous combination.35 So without bread, butter may be relatively benign.
In the raging debate about saturated fats, the truth probably falls in the middle. They are neither public health enemy #1 nor a health food.
With the Always Hungry Solution, you’ll eat lots of unsaturated fats, but also saturated fats in moderate amounts. Some foods high in saturated fat—like cultured dairy products, coconut, and chocolate—can make a delicious contribution to a high-quality diet, and there is no reason to avoid them. And a dash of heavy cream with fresh berries makes a much healthier dessert than the usual sugar-laden options. In addition, the Always Hungry Solution includes several servings of fish each week to provide long chain omega-3 fats. These polyunsaturated fats are the building blocks of critical anti-inflammatory cellular signals,36 and we generally don’t eat enough of them in the United States. A fish oil supplement may also be helpful, especially for those with chronic inflammation. Vegetarians can satisfy this nutritional requirement with flax oil or some types of nuts, but the omega-3 fat in plants is short chain and somewhat less efficient in the body.
(Mini Quiz #3 Answer: white bread)
ANIMAL OR VEGETABLE?
Mini Quiz #4:
Which has the most protein, ounce for ounce?
1. hard-boiled egg
2. chicken nuggets
3. hot dog
4. tempeh (a soybean product commonly consumed in some Asian countries)
(Answer here.)
Some diet books consider meat toxic. Others extol it as an exceptionally high-quality food. Here, too, the truth is likely in the middle.
Since the dawn of our species, animal products have made a major contribution to human nutrition, with concentrated amounts of protein, fat, and other vital nutrients. But today’s factory-farmed cows and chicken are different from those allowed to graze freely, which our grandparents would have eaten, and certainly from the wild animals our ancestors hunted.37 Industrial animal production also raises major ethical and environmental issues. And there simply aren’t enough wild animals for the world’s 7 billion people.
For adults, nutritional needs can be satisfied with a vegetarian diet containing dairy and eggs, or a (carefully managed) vegan diet containing no animal products at all. Contrary to common belief, some plant products provide high amounts of protein, such as tempeh with 23 grams in 4 ounces—comparing favorably to similar-size portions of hard-boiled eggs (13 grams), chicken nuggets (14 grams), or hot dog (12 grams).
There’s also some indication that replacing carbohydrate with plant rather than animal foods has special health benefits. Among approximately eighty thousand women in the Nurses’ Health Study consuming lower-carbohydrate diets, high consumption of vegetable protein and fat was associated with a 30 percent lower risk for heart disease over twenty years, whereas high consumption of animal protein and fat appeared to provide no such protection.38
One explanation for this finding is that the relative amounts of amino acids in animal protein stimulate more insulin and less glucagon release than those in plant protein—a hormone combination that has detrimental effects on serum cholesterol and fat-cell metabolism.39 Other possible downsides of a modern, animal-based diet include a less healthful profile of dietary fats, excessive iron absorption (especially for men), and chronic exposure to hormones, preservatives, and environmental pollutants.
Ultimately, we have a choice about how much meat, dairy, and eggs to eat. This decision involves more than health; it’s also a matter of personal preference, culture, ethics, and the environment. From an individual health perspective, the scientific evidence provides no reason to banish animal products. However, an emphasis on plants seems sensible, for ourselves and our planet. For this reason, the Always Hungry Solution provides vegetarian options for all recipes and meal plans.
(Mini Quiz #4 Answer: 4. tempeh)
PROBIOTICS, PREBIOTICS, AND POLYPHENOLS
Mini Quiz #5:
True or False: The microbes in our intestinal tract outnumber the cells in our body.
(Answer here.)
Humans have always had an intimate relationship with microbes, from constant exposures through food, water, dirt, animals, and one another. Our digestive tract contains a vast collection of bacteria, viruses, and other microorganisms, estimated to total over 100 trillion40—compared to about 35 trillion of our own cells in the body. Most of these microorganisms are benign or even beneficial. However, in Western societies, the biodiversity and richness of this gut microbiome may suffer for a variety of reasons: reduced exposure to microbes in our modern “hygienic” environment, our highly processed diet, and frequent antibiotic use.41
In addition to helping digest food, the microbiome plays an especially important role in maintaining the health and integrity of the gut lining—the critical barrier separating intestinal contents from our internal bodily environment. With a proper diet, beneficial bacteria produce fermentation by-products (such as short chain fatty acids) that nourish the colon, helping to reinforce the normally impermeable connections between adjacent cells. Beneficial bacteria also keep the immune cells in the intestinal tract functioning calmly through a complex series of interactions that are only now being identified. However, if the microbiome contains the wrong type or amount of bacteria, the intestinal lining may become damaged and leaky, allowing incompletely digested food and microbial breakdown products to be absorbed directly into the bloodstream. Long-term exposure to these toxic substances puts the immune system into overdrive, increasing the risk of diabetes and other obesity-related complications.42 In addition, leaky gut has been linked to an astonishing number of other diseases, including asthma, arthritis, eczema, psoriasis, irritable bowel syndrome, chronic fatigue syndrome, depression, schizophrenia, multiple sclerosis, Alzheimer’s, and more.43
What does this have to do with weight loss? The gut microbiomes of people with obesity and those without appear to differ in consistent ways.44 When Danish researchers examined 192 adults of varying body weight, they were able to identify two distinct groups based on gut bacteria composition. Compared to individuals with high bacterial richness, those with low richness had more insulin resistance and chronic inflammation, and tended to gain more weight.45
In a study that would have seemed straight out of science fiction a few years ago, separate groups of mice raised in a germ-free environment were given fecal transplants from human twin pairs who differed in body weight (one lean, the other heavy). Astoundingly, mice that received transplants from the heavy twins became significantly fatter than mice receiving transplants from the lean twins. Furthermore, cohousing the animals together allowed bacteria from the lean mice to spread to the other group, protecting them from excessive weight gain.46
How do we maintain a healthy microbial garden in our gut? Clearly, the answer isn’t to abandon handwashing and other hygienic practices. Instead, by analogy to an actual garden, we need to plant the right seeds, fertilize the soil, and carefully eliminate weeds. This is accomplished with probiotics, prebiotics, and polyphenols.
Probiotics are live beneficial bacteria (and sometimes yeast) present in certain foods and nutritional supplements. Prebiotics are the components of plants, typically grouped under the term “fiber,” that can’t be digested in the small intestines and instead provide food for beneficial bacteria in the colon. And polyphenols are plant-derived chemicals, abundant in colorful fruits and vegetables (especially berries), that can slow the growth of toxic microbes—allowing beneficial bacteria to flourish.47 In addition, some polyphenols, like curcumin from the spice turmeric, can be absorbed from the intestinal tract and exert an anti-inflammatory effect throughout the body.48 Whole plant foods and live fermented products provide these three microbiome-enhancing factors, helping to keep this internal ecology working for rather than against us.49
Whether you choose standard or vegetarian options, all phases of the Always Hungry Solution provide an abundance of whole plant foods that will cultivate a vibrant and well-behaved microbiome. Yogurt also appears frequently on the meal plan—make sure to choose products with live cultures. Try to include other dietary sources of probiotics as often as possible, such as authentic fermented pickles (not the versions made with vinegar), sauerkraut, kimchi, and kefir. You may also want to consider taking a high-quality probiotic supplement. In addition, the recipes use a liberal amount of spices, to provide both flavor and rich sources of polyphenols. And avoid emulsifiers (like carboxymethylcellulose, polysorbate-80, and lecithin) which may break down the intestine’s protective mucus lining.50
(Mini Quiz #5 Answer: True)
SUGAR AND ARTIFICIAL SWEETENERS
Mini Quiz #6:
Is fructose toxic?
(Answer here.)
In the 1990s, sugar was commonly considered harmless and sugary beverages were touted as “fat-free.”51 Today, some notable experts regard high consumption of fructose, a primary component of sugar, to be the main problem with the American diet, uniquely responsible for the twin epidemics of obesity and diabetes.52 As with some other dietary debates addressed in this chapter, the truth is probably more nuanced.
Most sugars are composed of three basic building blocks—glucose, fructose, and galactose—singly or combined in various ways. The common sweeteners, such as table sugar (sucrose), maple syrup, honey, and high-fructose corn syrup, contain approximately equal proportions of glucose and fructose. Since fructose tastes much sweeter than glucose or galactose, sugars without this component (such as lactose and maltose) have limited use.
With the obsessive focus on decreasing fat intake since the 1970s, consumption of fructose-containing sweeteners rose substantially, especially in the form of sugary beverages.53 Might this trend have contributed to the obesity epidemic? Unlike glucose, which can be used by all cells in the body, fructose is metabolized almost exclusively in the liver. Too much at one time overwhelms the liver, with the excess being diverted into the production of new molecules of fat. Eventually, fatty liver and other metabolic problems may result.
Several studies have documented insulin resistance, higher triglycerides, higher blood pressure, and increased belly fat among research participants given diets with about 150 grams of fructose per day compared to diets with an equivalent amount of glucose.54 However, these studies have been criticized for providing unrealistically large amounts of fructose, triple the average intake of about 50 grams.55 Moreover, high consumption of fruit—the primary natural source of fructose—is associated with better, not worse outcomes in observational studies.56 In possibly the only clinical trial of its kind, seventeen South African adults were instructed to follow diets consisting primarily of fruit for a minimum of twelve weeks, with small amounts of nuts to satisfy nutritional requirements. The participants consumed on average twenty servings a day or more, likely containing at least 200 grams fructose. At the end of the study, the investigators observed virtually no adverse effects. To the contrary, body weight and other heart disease risk factors tended to improve despite this massive dose of fructose.57
Similar to the concept of glycemic index, the main concern with fructose probably isn’t total amount, but rather the rate of absorption into the body.58 High-GI bread has an adverse impact on metabolism compared to low-GI beans, though both have about the same amount of carbohydrate in a serving. After we eat conventional sweeteners like high-fructose corn syrup, table sugar, or honey, fructose hits the liver rapidly. Eating more than a small amount of any of them can cause fructose to spill over into metabolic pathways leading to fat production. By contrast, fructose in whole fruit is absorbed slowly, because it’s surrounded by fiber and sequestered within the cells of the fruit. For this reason, even large amounts of whole fruit generally won’t overtax your liver. The situation is like alcohol, another compound metabolized primarily in the liver. The liver can usually handle one drink, but seven at one time would cause damage.
Fructose isn’t inherently toxic, and whole fruit is among the healthiest foods we can eat. Nor is glucose benign when present either in sweeteners or rapidly released with digestion of high-GI foods. Simply replacing fructose-containing sweeteners with highly processed, glucose-based carbohydrate (either fructose-free sugar or starch) may miss the point, as suggested by two small clinical trials from the 1970s. In one study, nineteen men on an Antarctic expedition were given a standard diet with 400 calories a day from table sugar, or an experimental fructose-free diet using glucose from corn syrup. The investigators reported no difference in calorie intake and body weight, and no consistent differences in blood sugar levels after at least fourteen weeks on each diet.59 In another study, nine adults were examined in a metabolic ward on a high-sugar diet (70 percent of carbohydrate as table sugar, an average of about 675 calories a day) or a sugar-free diet with additional wheat and potato starch. After four weeks on each diet, there were no differences in body weight, glucose tolerance, insulin levels, or serum lipids.60 We certainly need more research on the topic, but as I see it, the similarities among all concentrated sugars and refined starch outweigh their metabolic differences.
How about artificial sweeteners, which contain no fructose or glucose at all? With saccharin instead of sugar, can we have our cake and eat it, too? Although artificial sweeteners—also including acesulfame, aspartame, neotame, and sucralose—have essentially no calories, they still affect the body.61 These synthetic chemicals stimulate taste receptors for sweetness hundreds to thousands of times more powerfully than sugar, with possible detrimental effects on diet quality. People who regularly consume artificial sweeteners may find naturally sweet foods (like fruit) unappealing, and unsweet foods (like vegetables) intolerable. Artificial sweeteners may also cause insulin secretion, driving calories into fat cells and stimulating hunger.62 In addition, fat cells have been reported to contain sweet taste receptors—similar to those on the tongue. Artificial sweeteners may promote fat cell growth by stimulating these receptors or in other ways.63
In the Always Hungry Solution, you’ll avoid all added sugar in Phase 1 (except for a small amount in dark chocolate). In Phases 2 and 3, you can add back a moderate amount, based on individual tolerance. But it’s best to satisfy desire for sweetness mostly the old-fashioned way—with fresh fruit. When using added sweetener, choose pure maple syrup or honey instead of table sugar when possible. These less-refined sweeteners contain nutrients and polyphenols that may partially counterbalance the sugar. They also have stronger flavor, so you can get by with less. None of the recipes and meal plans contains artificial sweeteners. After giving up the hypersweetened stuff, you may be surprised to discover just how sweet and flavorful fresh seasonal fruit can taste.
(Mini Quiz #6 Answer: No)
SALT
Mini Quiz #7:
True or False: Sodium consumption should be reduced as much as possible.
(Answer here.)
Many processed foods have a tremendous amount of salt that, together with sugar, helps make cheap industrial food products taste good. A single serving of Jack in the Box Crispy Chicken Strips contains 1,580 milligrams of sodium—more than the government recommended total daily limit for everyone over age fifty.64 High intake of salt can cause hypertension, increasing the risk for heart attack, stroke, and kidney disease. Since only a small portion of the sodium in our diet normally comes by way of the kitchen saltshaker, eliminating highly processed foods naturally lowers salt consumption. But when it comes to salt, is less always more?
The concentration of sodium in the blood is controlled to within a very narrow range. When intake rises, the kidneys excrete the excess. When intake falls below 3 to 4 grams a day, the body compensates by activating powerful hormones, called the renin-angiotensin system (RAS), which helps the kidneys hold on tightly to salt.65 The problem is, receptors for RAS are present not only in the kidneys, but also in fat cells, muscle, the pancreas, the lining of the blood vessels, and elsewhere. Overactivity of this system has been shown to cause fat cell dysfunction, insulin resistance, and inflammation—the fundamental problems linking obesity to diabetes and heart disease. Blocking RAS, such as with the widely used ACE inhibitors, lowers risk for these two major killers out of proportion to the drugs’ effects on blood pressure.66
Based on this reasoning, excessive restriction of salt could have adverse consequences, a possibility supported by several lines of research. The Cochrane Collaboration (an international organization that sponsors systematic reviews of scientific evidence) examined 167 randomized clinical trials from 1950 to 2011 comparing low-salt to high-salt diets. They found that among whites without hypertension, sodium reduction produced a decrease in systolic blood pressure of only 1 millimeter of mercury and no decrease in diastolic blood pressure. African Americans and people with hypertension experienced somewhat greater improvements in blood pressure, ranging from 2 to 6 millimeters of mercury. However, sodium reduction also increased RAS activity, adrenaline, cholesterol, and triglycerides, suggesting that it may worsen insulin resistance.67
In a recent study in the New England Journal of Medicine that followed about one hundred thousand people for an average of four years, the risk of major cardiovascular disease or death was lowest among those with sodium intakes ranging from 3 to 6 grams—well above currently recommended levels—compared to either lower or higher amounts.68 These findings received a great deal of attention in the media, but must be interpreted cautiously. Individuals at risk for heart disease might be more likely to follow medical advice and reduce their salt consumption. So the increased risk in this observational study among those consuming a low-salt diet might reflect preexisting disease, rather than the effects of sodium itself.
The jury is still out regarding optimal levels of intake. But one thing seems clear: A fast-food, junk-food diet provides too much salt in addition to all the highly processed carbohydrate (an especially bad combination for heart health). For people with hypertension or other special risk factors, low sodium intake significantly lowers blood pressure—a major public health goal. But for everyone else, sodium reduction from average to very low levels appears to have negligible benefit for blood pressure and may cause metabolic problems. Potentially more effective ways to control blood pressure may be to lower intakes of added sugar69 and other highly processed carbohydrates,70 reduce stress, and increase physical activity—all components of the Always Hungry Solution.
The amount of sodium on the program diet will total less than 3 grams a day for most people (depending on how much salt you add to your meals), below average levels in the United States throughout the last half century.71 But if you are following a low-sodium diet, the recipes and meal plans can be easily adapted to your needs.
(Mini Quiz #7 Answer: False)
FOOD ADDITIVES AND POLLUTANTS
Mini Quiz #8:
How many food additives are FDA approved?
(Answer here.)
Ultraprocessed industrial foods lack a great many health-promoting qualities, such as high-quality fats, slow-digesting carbohydrates, essential vitamins and minerals, fiber, probiotics, and polyphenols. They do contain a staggering array of preservatives, colorants, flavorings, emulsifiers, and other artificial ingredients. In addition, pesticides, plastics, antibiotics, heavy metals, and other pollutants inadvertently find their way into our food and water supply. Some of these substances interfere with hormones in especially harmful ways for fat tissue.72 Recently, two physicians from the University of Chicago made the provocative (and alarming) argument that our fat cells are “under assault” from the toxic chemicals in our environment.73 As just one example, rats exposed to low-dose bisphenol A (BPA)—a chemical that was widely used in plastic food containers—around the time of birth gained excessive weight and showed extensive changes in the behavior of their fat cells.74
In truth, most artificial additives and pollutants in our food have never been thoroughly tested for long-term health effects.75 And who knows how these chemicals interact in various combinations inside the body? By emphasizing whole, natural foods, the Always Hungry Solution reduces these exposures substantially. You can further reduce exposures by purchasing organic or pesticide-free produce when feasible and using a good-quality water filter at home.
(Mini Quiz #8 Answer: More than 3,000, not including substances “Generally Recognized as Safe”76)
BONUS—Mini Quiz #9:
True or False: Sour Triple Berry Shock Fruit Gushers contain berries.
(Answer below.)
(Mini Quiz #9 Answer: False. The ingredients include pears from concentrate, sugar, dried corn syrup, corn syrup, modified cornstarch, fructose, grape juice from concentrate, partially hydrogenated cottonseed oil, citric acid, maltodextrin, cottonseed oil, carrageenan, glycerin, monoglycerides, sodium citrate, malic acid, potassium citrate, ascorbic acid, flavors, agar-agar, artificial colors, and xanthan gum.77)
PERSONALIZED DIETING—PREPARING FOR PHASE 3
Mini Quiz #10:
Which biological factor best predicts how individuals will respond to diets with varying amounts of carbohydrate?
1. Blood type
2. Eye color
3. Insulin secretion
(Answer here.)
On average, human DNA is 99.9 percent identical from one person to the next. So it’s not surprising that the contours of a healthful diet—one that satisfies all nutritional requirements and keeps levels of insulin and inflammation low—don’t differ among people very much. A diet based on whole, natural, slow-digesting foods lowers everyone’s risk for chronic disease, regardless of body weight, age, sex, race, or country of origin.
But just as risks for many specific diseases vary between individuals, so too does tolerance for poor eating patterns. Some people have a resilient and adaptable metabolism, especially when young and physically active. Others seem to be exquisitely sensitive to processed carbohydrates, certain types of fat78 (potentially explaining some of the controversies previously considered in this chapter), or wide variations in the relative proportions of major nutrients in the diet. My collaborators and I have explored this issue for more than a decade and found that insulin secretion plays a key role.
After eating carbohydrate, the pancreas secretes insulin to keep blood sugar from rising too high, but the amount and timing of insulin secretion varies substantially from person to person. To assess this difference in research, we give volunteers (or sometimes experimental animals) an oral glucose solution and then measure insulin in the blood thirty minutes later—the test is called the Insulin-30 level.
In a study published in the American Journal of Clinical Nutrition,79 we followed 276 middle-aged adults in Quebec for six years, dividing them into categories based on diet. Overall, the participants gained about 6 pounds (quite typical for this age group), but with huge individual variation—ranging from a 20-pound weight loss to a 30-pound weight gain. For those consuming a high-carbohydrate/low-fat diet, Insulin-30 strongly predicted this variation. That is, people with low insulin secretion gained on average virtually no weight, whereas those with high insulin secretion gained on average more than 10 pounds. In contrast, Insulin-30 had no relationship to weight gain among those consuming a low-carbohydrate/high-fat diet. Furthermore, hypoglycemia several hours after consuming glucose was more severe in the high-carbohydrate/low-fat group, and predicted weight gain.
This study suggests that some people are especially sensitive to carbohydrate for biological reasons. A high-carbohydrate diet exacerbates their underlying tendency to secrete too much insulin, creating a vicious cycle of high insulin followed by low blood sugar that leads to excessive weight gain. But these individuals can reduce this risk by switching to a lower carbohydrate diet—or, as we’ll see next, a low-GI diet.
In chapter 3, we considered an animal study published in Lancet80 that found greater body fat among rats fed a high-GI diet compared to those fed a low-GI diet. Here, too, Insulin-30 strongly predicted how much weight and fat each animal in the high-GI group gained, accounting for about 85 percent of the total variation. (This is a remarkably high figure; for comparison, all known genes account for less than 10 percent of the variation in body weight among humans.) In the low-GI group, Insulin-30 was unrelated to weight gain (see the Insulin Secretion and Weight Gain figure here).
Insulin Secretion and Weight Gain Among Rats Fed High- or Low-GI Diets
My colleagues and I tested this hypothesis in a long-term clinical trial published in JAMA.81 We measured insulin secretion in seventy-three young adults and then randomly assigned them to a low-GL or low-fat diet for eighteen months, providing the same amount of dietary counseling and other supports to both groups. Among individuals with low Insulin-30, weight loss did not differ significantly between the two diet groups. However, individuals with high Insulin-30 (above 57.5 microunits per milliliter) lost 10 pounds more on the low-GL diet compared to the low-fat diet. Moreover, those with high insulin secretion assigned to the low-fat diet tended to drop out of the study more than anyone else—an indication that this diet wasn’t working for them.
The good news is that a person’s susceptibility to diet may not be set in stone. After just one month on a low-carbohydrate diet, the cells in the pancreas that make insulin seemed to calm down, allowing individuals with high Insulin-30 to be able to tolerate more carbohydrate without a slowdown in metabolic rate (at least for a while).82 In this way, Phases 1 and 2 of the Always Hungry Solution may reset metabolism, allowing previously sensitive people to have some processed carbohydrates in Phase 3 without adverse effects.
Undoubtedly, there are other biological differences among people that affect response to different diets (though the evidence for blood type is lacking). In addition, physical activity level plays a role. Research participants given five daily servings of sugary drinks showed increases in triglycerides, inflammation, and insulin when they were limited to walking no more than 4,500 steps per day. But these adverse changes did not occur when the participants walked more than 12,000 steps a day.83 Eating lots of white rice may not cause metabolic problems for peasants in China doing regular manual labor. But as millions of Chinese migrate from farms to cities—bringing their high-carbohydrate diet and leaving behind the high level of physical activity—rates of diabetes have skyrocketed.84
Of course, on top of biological differences, we all have specific food preferences, cultural practices, time availability and constraints, levels of discipline, and individual health goals. For that reason, we’ve crafted the Always Hungry Solution with maximum flexibility, so that everyone can find the right balance between their body’s needs and their personal preferences. Phases 1 and 2 are designed to retrain fat cells, boost metabolism, and help you find the optimal weight for your body. Phase 3 allows for personalization. Use the Daily Tracker and Monthly Progress Chart (see Appendix B) to follow your weight, hunger, cravings, energy level, and overall well-being. If these remain stable as you add back some processed carbohydrate, then feel free to enjoy the extra flexibility your metabolism allows (within reason). If not, cut back, or return to Phase 2 permanently. And remember, the fleeting moments of pleasure from eating poor-quality food pale in comparison to the enduring rewards of feeling good.
(Mini Quiz #10 Answer: 3. insulin secretion)
You’ve now reached the end of part 1, where we explored a radically different way to think about diet, body weight, and chronic disease prevention. In part 2, we put all this information together into the three-phase program to achieve permanent weight loss.