To understand the power of food, you have to learn about what it does once you chomp, chew, and churn it through your body.
In other parts of life, you probably don’t give a hoot about the inner workings of your stuff as long as it functions properly. Who cares what hoses, tubes, and wires go where as long as your car gets you from point A to point B? Do you really need to understand the Instagram algorithm as long as you can post your favorite sunset pic? Unless you have a special or professional interest in looking under the hood of your day-to-day machinery, you, like us, probably take a lot of things for granted.
Food, however, is different. You should know about how it’s built and how it works because its effect, function, and composition aren’t the same from bite to bite. And its behavior is certainly not the same once it’s torpedoed from your mouth to your digestive system. Taking your food for granted is a recipe for bigger jeans, more doctor visits, and an earlier expiration date.
The reality is that when you understand the fundamentals of food and how your body reacts to it, it becomes that much easier to manage the When Way of eating. Here, we’ll take you through three major macronutrients and how they’re broken down and used in your body. Then, we’ll explain why they’re so important to your health.
THE MACRONUTRIENTS: POWER AND EFFECTS
Food is more than just photographic fodder for your Facebook feed; it contains the building blocks you need to develop and maintain your body, supplying energy and raw materials so that organs, tissues, and cells are powered to work and renew 24/7. No fuel, no you.
This task of fueling is achieved through a cocktail of components that mostly come in the form of the big three macronutrients: carbohydrates and fat (used for energy) and proteins (the building blocks of the body). These are called macronutrients because we need them in large amounts.
Food also includes other necessary elements, known as micronutrients, which include vitamins, minerals, phytochemicals, and antioxidants. Together, these macro- and micronutrients help dictate your overall well-being, including your weight, your waist size, and your overall health risks.
Now, keep in mind that although it may seem simple to classify particular foods as proteins, carbs, or fats, the reality is that most foods include a combination of macronutrients (that is, fish has protein and fat; beans have protein and carbohydrates).
What does that mean for you? Well, you don’t have to think about fractions or do complex calculations every time you eat. But you should understand why certain foods are good sources of macronutrients, so you can learn how to use their benefits to your health advantage.
Carbohydrates: Carbs are like 1980s hair bands—like them or not, they usually elicit an immediate reaction. Some of us associate the word “carb” with breads, pasta, and cake; for others, just looking at them means gaining four pounds. Athletes employ them skillfully, often “carbo-loading” before a big race or game. Today, the diet industry seems to contain two camps: carb haters and carb embracers. So let’s break down what exactly this hot-button macro is all about.
Put simply, carbohydrates are sugars. Hang on, hang on—that doesn’t mean that all carbohydrates look like a bowl of pudding. Sugar is a chemistry term for certain types of molecules. Because there are many forms of sugar molecules, there are many forms of carbohydrates. The main ones? Simple sugar, starch, and fiber. The most basic building block of these is a sugar molecule, which the body can break down and turn into glucose, the main energy currency of the body.
Glucose is like the body’s form of Red Bull; it provides quick fuel as soon as it’s available in the bloodstream. Insulin, which is secreted by the pancreas, delivers that glucose into your cells to be used for energy. Glucose isn’t stored, so if it’s not immediately used, it is converted into a substance called glycogen. (Think of glycogen as six extra cans of Red Bull sitting on your shelf, ready to provide energy if yours runs out.) Glycogen is a form of medium-term energy stored in your liver and muscles; your body can call on it as needed and can reserve about two days’ worth. Glycogen is always stored in a hydrated form—again, like Red Bull—meaning it has about three times its weight in water. So when you go on a low-carb diet, most of the weight that you lose rapidly is water that disappears when you deplete glycogen stores. As soon as you go back to carbs, you build up the stores and associated water, and the weight comes back.
Although your body relies on carbohydrates for energy, it’s better to obtain it from complex carbohydrates, rather than simple ones. Simple sugars—for example, those found in table sugar, white flour, and cornstarch—immediately start acting out in your body, supplying instant energy, but wreaking biological havoc on many of your inner systems (including damaging the lining of your blood vessels, which can lead to high blood pressure, high inflammation, and greater risk of heart, brain, and kidney trouble).
Complex carbohydrates—for example, whole grains and fiber—are broken down by the body more slowly, so the sugars are released gradually into the blood. This way of supplying energy provides for a more calm, efficient functioning of your bodily systems.
As you’ll see later on, simple sugars are the ones that are more associated with weight gain and diabetes, not to mention wrinkles and impotence. That’s why processed foods, baked goods, and other “white carbs” are the ones you should generally try to avoid, while fruits, vegetables, beans, and whole grains are the carbs to cultivate.
Think about it as the difference between frantic and calm. Simple carbs are like crazy partiers who are bouncing off walls, breaking lamps, and creating all kinds of messes. Sure, they can be fun for a moment, but the long-term damage probably isn’t worth it. Complex carbs govern your body with stoicism and confidence, exuding a quiet leadership that makes your body work efficiently and cleanly.
Fat: For a long time, people considered fat to be a four-letter word (and we’re not talking about “phat”). Experts believed that a high-fat diet was associated with a big-belly body; fat in food equaled fat on the body. Thank goodness that dogma has changed. Today, many, many people realize that fat isn’t necessarily what makes people larger (more on that in a moment). Instead, fat (the macronutrient kind) should be thought of as a component of food, one that has a variety of chemical interactions.
Used for long-term storage of energy, fat contains more than double the energy of carbohydrates (2.25 times, to be exact). It comes in two forms: saturated and unsaturated.
Saturated fats are solid at room temperature and are typically derived from animal products (coconut and palm oils are exceptions as plant-based saturated fats). These are the least healthy kinds of fat, as they’re associated with increased inflammation and increased blood LDL cholesterol.1 Worse, they come with proteins that change the bacteria in the gut to make them produce inflammation throughout the body.2 Recent studies suggest that saturated fat may also increase the risk of insulin resistance.3
Unsaturated fats are those derived from plants. There is consistent evidence that replacing saturated fats with unsaturated fats decreases inflammation, risk of cancer, mental decline, “bad” LDL cholesterol, and risk for heart disease.4,5,6,7,8 Unsaturated fats can be broken down further into polyunsaturated fats (corn oil, sunflower oil, safflower oil, and omega-3 fatty acids found in fish) and monounsaturated fats (olive oil, peanut oil, canola oil, avocados, and most nuts). Studies have suggested that a diet rich in monounsaturated fats is associated with less visceral fat9—the worst kind, which can accumulate around the organs.
Polyunsaturated fats make up the outer coating of cells, but cannot be made in the body; therefore, we rely on outside sources for these (wild salmon is by far the best). Numerous studies show that people with higher levels of omega-3 fats in their blood have reduced risk of heart disease and better cognitive function.10,11 (Salmon, by the way, don’t make the precious fish oil—DHA—themselves; the fish get it by eating algae.)
What’s the Deal With Trans Fats?
Trans fats—hydrogenated oils—are the worst kinds of fats. They’ve been linked with heart attack and stroke, and possibly with cancer and brain dysfunction. Trans fats were originally used to help improve the taste and texture of processed foods, but the health risks have made them a major villain in the nutrition world. The U.S. Food and Drug Administration (FDA) has banned them from food manufacturing—and they’ll be off the shelves by 2020 if regulations stay in place. But trans fats are naturally present in some foods like beef, pork, butter, and milk, which are also high in inflammatory ingredients. This is one of the reasons we don’t recommend these foods. (See Chapter 4 for more on this.)
Protein: Proteins can be used for energy by being turned into glucose, but that’s not their main purpose. Proteins are truly the building blocks of life. They are made up of amino acids that, like metal, can be combined into wide varieties of machines that the cells of your body need to run. Although most people think of meat as protein, all cells contain a lot of it—even the ones in celery. The big difference between the proteins in plant cells and animal cells is the amino acids; animal proteins contain a wider variety of amino acids than plants. The body cannot internally make many amino acids, which is why vegetarians should eat a wide variety of foods to receive the full mix.
These days, our culture is as obsessed with eating protein as it is with viral cat videos. In fact, many Americans eat almost twice as much protein as they actually need.12 Proteins are worth four calories per gram, just like carbs, so eating too much of them can lead to weight gain. Although high-protein diets are all the rage, we don’t recommend eating more than the average American already eats—about 82 grams a day, the amount in about 10 ounces of a grilled chicken breast—because very high-protein diets can stress the kidneys.
WHY FOOD MATTERS
It’s one thing to know your macros and how they function. But the real value is understanding their interactions in the body. What happens as your body breaks them down?
AFTER YOU SWALLOW |
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Esophagus | Muscle at the bottom relaxes to allow food and liquid to pass through to the stomach. |
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IT STARTS GETTING GOING |
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Stomach | It mixes your foods with digestive juice, to start breaking things down, and slowly empties out to the intestines. |
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AND THE FOOD MIXES WITH DIGESTIVE JUICES |
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Small Intestine | The mix continues to get churned up and combined with more and more specific enyzmes. The walls of the small intestine absorb the digested nutrients and put them into the bloodstream before moving the mixture into the large intestine, where the waste products start to move on out. |
Now, the reason that the kind of macros you ingest is so important is because of their impact at any given time. Take carbs, for instance. Your body needs to tightly control the amount of glucose in your blood; when it loses that ability, we call that diabetes. Elevated levels of blood sugar are associated with a whole host of health problems, including blood vessel damage.
Why is that important to avoid? These vessels are key to supplying your essential organs with nutrients and to removing waste. Disease in these vessels leads to damage throughout the body. Most notably, people with diabetes can develop kidney failure, eye disease, heart disease, stroke, mental dysfunction, and poor wound healing.
Eat too much food of any kind or have too many simple sugars |
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Your body, via insulin, cannot keep up to carry away the glucose to use as fuel |
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Glucose gets stored as fat and the circulating glucose can trigger processes that lead to damaged arteries |
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Diabetes, weight gain, heart problems (metabolic syndrome) |
There’s a simple action-and-reaction equation that everyone should know: When you eat carbohydrates, your blood sugar goes up. The simpler the carbohydrate and the more of it you eat, the more your blood sugar increases.
With that rise, insulin is released from your pancreas into your blood to help deliver the glucose that will be used for energy—and to bring your blood sugar back to a level that won’t cause damage. Insulin stimulates muscle and fat cells to take glucose out of the blood, delivering it like a Fed-Ex package from the outside to the inside of those cells. In addition, insulin stops the breakdown of fat stored in fat cells (no need to break down fat if there is a lot of glucose around) and stimulates the liver and muscles to store glucose as glycogen (the stored form of carbohydrates used for energy).
Here’s the catch: Your liver has a limited capacity for glycogen. Any extra glucose that is delivered to the liver is converted to fatty acids called triglycerides, which are the main type of body fat. They are stored in the liver or are packaged in the form of LDL (the bad cholesterol) to be shipped out into your bloodstream. Triglycerides are designed to help repair nicks in your blood vessels, but in excess they accumulate to become fat and then atherosclerotic plaque in the walls of your blood vessels.
That’s why eating extra glucose increases your risk of developing fatty liver diseases (yes, this has nothing to do with alcohol, and 30 percent of the U.S. adult population is estimated to have a fatty liver condition).13 Fatty liver is associated with insulin resistance, the inability of insulin to be an effective driver for delivering glucose out of your blood and into your cells. More sugar in your blood means more damage to your body and more stored fat.
Insulin resistance is as if the cells are a little hard of hearing. To get the attention of the cells, the pancreas (the organ that makes insulin) has to yell by making even more insulin to get a response. If you develop insulin resistance, three things happen: One, when you eat a typical amount of glucose, your blood sugar is going to be higher than normal because the insulin cannot get the glucose into the cells; the cells don’t hear the insulin ring the bell. Two, because your blood sugar remains elevated, your pancreas is going to pump out more insulin than is actually needed. Three, that extra sugar attaches to your proteins, causing them to be less functional.
This scenario is a problem: One in three Americans knows they have prediabetes14 (and countless more are not aware), which makes them even more vulnerable to full-blown type 2 diabetes.
And remember from the last chapter: When you eat also plays an important role in your blood sugar levels. Our bodies tend to be more resistant to insulin later in the day (it’s almost like we have prediabetes at night), so the later we eat, the more likely we are to raise our blood sugar higher.
Being overweight can make you insulin resistant, but scientists are still debating whether or not such resistance sends you into a spiral of accumulating more fat (and thus becoming more insulin resistant). That’s because eating a meal that increases your blood sugar substantially can cause a roller coaster ride of blood sugar levels. In other words, eating a high-glycemic food (see glossary) is associated with a rapid rise in blood sugar, which in turn is accompanied by a rapid increase in insulin. The insulin causes your cells to take up the glucose and drop your blood sugar below normal fasting levels. When this happens, you crave carbohydrates and start the cycle again. So eating carbs that have what are called a high-glycemic index can cause a vicious cycle of rising and falling insulin levels, which cause you to overeat.
This begs the question: How do you get fat? Any of the macronutrients—fat, carbs, and even protein—can cause you to gain weight if you eat too much. Because fat is the most energy-dense of the three macronutrients, eating a lot of it can quickly lead to too many calories in and not enough out. What the body cannot use for energy or fit into those limited glycogen stores will be stockpiled as fat that your body wants to keep in case you run out of energy. (In terms of evolution, this process came in handy during times of famine.)
You store some fat under your skin (that’s called subcutaneous fat). But the fat that surrounds our organs, called visceral fat, is more dangerous. It’s been linked to metabolic disturbances like insulin resistance and type 2 diabetes, as well as increased risk for cardiovascular disease.15 It may also be associated with certain types of breast cancer in women, and with prostate cancer in men.16,17
To find out how much visceral fat you have, you could do a body scan. But an easy way to determine your risk is to measure your waist-to-height ratio. A recent study has shown this is the best approximation of body fat—even better than the BMI measure.18 The ideal ratio is a waist size that is half your height or less. To measure your waist, measure around the belly button, and feel free to suck in your gut because we are more concerned about the fat inside than on the outside.
The million-dollar question, of course, is how do you get rid of the fat? Your body wants to use glucose as fuel first, because fat is better for long-term storage. You’re always using a combination of both, but to burn more fat than glucose, you need to burn through your sugar stores and get to the fat.
Eating the When Way can help. As you go through the next few chapters—offering major eating guidelines and the optimal eating plan for eating every day—keep the what and when in the front of your mind. We’ll front-load your days to be circadian-friendly, and we’ll pack them with the nutrients that are best for your body. This combination has big payoffs: You’ll be healthier, you’ll lose weight (if that’s one of your goals), and you’ll have more energy.