The next clue comes not from a laboratory but from a garden, where a woman named Masu is working. She spent the morning cleaning her house, doing her chores, and tending her plants, and she is now picking lettuce, spinach, and green onions for her lunch. The fact that she turned 100 last year and is still active and in good health is not remarkable here. Many people in Okinawa live to a ripe old age. Her cousins are 105 and 106.
She has been through a lot over the years, including the hardships of World War II, when a quarter of the civilian population of Okinawa died and life for the rest was precarious. Foods from the family garden sustained them during those difficult times, just as they do today.
In the post–World War II period, Americans brought their own food preferences, and McDonald’s and KFC eventually set up shop on the island. But Masu has never been to either one. Her number one staple is the sweet potato, with rice a close second. And she has plenty of greens, daikon radish, seaweed, and nigauri (or “bitter melon”), which is a bit like a cucumber. The occasional bit of fish or pork will find its way onto her plate, but these are not staples.
Her daughter moved to the United States and started a Japanese restaurant, where she serves many of the same foods that kept her family healthy. Have they heard of Alzheimer’s disease in Okinawa? Yes, but it’s not very common and, as her daughter told me, “that’s only in really old people.”
Masu didn’t know it, but during World War II, sailing offshore on an American destroyer was a young military surgeon with whom she had quite a few things in common. Ellsworth Wareham, MD, was originally from Alberta, Canada. He moved to Loma Linda, California—about an hour east of Los Angeles—to go to medical school. After Pearl Harbor turned the world on its head, he found himself sailing past Okinawa. And what he was eating was very similar to a lunch Masu might have prepared for herself. As soon as hostilities ended, he pursued advanced studies in cardiothoracic surgery and eventually ended up back at Loma Linda University, serving as chief of cardiothoracic surgery.
The reason I am telling you all this is because just as there was something that set Okinawans apart from people in most other countries—their amazing health and longevity—there was something that set Ellsworth apart from other surgeons. He had energy they didn’t have. When they retired, he kept going. Age sixty-five was just a number. As he reached seventy, seventy-five, and eighty years, he still donned his gloves and surgical gown and strode into the OR every day, just as he always had.
This can’t go on forever, he told himself. So, arbitrarily, he decided that ninety-five ought to be the age when he would retire. And when that day finally arrived, that’s what he did. Even though his colleagues tried to talk him into staying—they wanted his experience, steady hands, and clear mind at the operating table and even offered to pay his malpractice insurance premiums if he would stay—he figured it was time. He decided to hang up the scalpel—sort of. Today you’ll find him operating on the bushes and trees on his two-acre lawn. At six feet tall and 172 pounds, he feels great. “I never have any aches or pains. I rarely have a cold or the flu.”
So what is he eating? When he was growing up, Ellsworth’s family raised cattle for beef and milk, and chickens for eggs. And he didn’t particularly like the look of any of it.
“Looking after the animals, I found milk to be rather unhygienic, when you see where it comes from. The chickens were not too clean either, so I didn’t care for their eggs. I had them once in a while, but not often. I never cared for meat or dairy products.” And then, arriving in Loma Linda, his diet took another step. “I found out that I didn’t need animal products at all. In fact, I was better off without them. And that was it. For the past four decades, I’ve pretty much avoided anything from animals.”
Anywhere else, that might have been an odd choice. But Loma Linda is home to many Seventh-day Adventists, whose religious teachings put a huge premium on clean living. Tobacco, alcohol, and even caffeine are frowned on, and meat eating is discouraged, too. So skipping animal products entirely was not a particularly unusual choice.
Sailing by Okinawa, he would have loved a serving of Masu’s sweet potatoes and vegetables. His own meals are just as simple. Fresh fruit and whole-grain cereal with soy milk for breakfast; baked beans, vegetables, corn on the cob, soy yogurt, and occasional faux “meats” later in the day; with almonds or peanuts as snacks. He enjoys his menu and the health and longevity it has brought him. He recalled a Wall Street Journal article that said that other than breast milk, all tastes are acquired. “In other words, your tastes adapt to what you eat. If you eat fatty, salty foods, those are the foods you’ll crave. And if you break away from them, you’ll come to enjoy healthier foods.”
Okinawa and Loma Linda are places where people enjoy surprisingly good health—including healthy brain function—well into advanced age. In 2005, these remarkable geographic “blue zones” were described by Dan Buettner in a National Geographic pictorial. Other “blue zones” include Sardinia, Italy; Ikaria, Greece; and Nicoya Peninsula, Costa Rica.
In all these places, people’s food choices have one thing in common: They emphasize foods from plant sources. That means sweet potatoes, rice, and vegetables in Okinawa; vegetables, beans, and fruit in Loma Linda; whole-wheat bread, fava beans, and nuts in Sardinia; corn and beans in Costa Rica; bread, olives, greens, and beans in Ikaria.
Fargo, North Dakota, is not a blue zone. Growing up in Fargo, our summers were green, our winters were very white, and you could always smell the sugar beet factory when the wind was in the right direction. My paternal grandfather was a Midwestern rancher. So was my great-grandfather and every generation before that, so far as I could trace. If it walked on four legs, it was likely to end up on the table.
Two legs, too. Ducks and geese flew over the North Dakota wetlands, and every fall my father took his sons out hunting. Eviscerating the smelly carcasses on our cement basement floor, we would not have qualified for Top Chef. We had very limited appreciation for vegetables or fruits.
My own meat-laden diet was made worse by my summer job, tending the deep-fryer at McDonald’s. By the end of my shift, I probably had more grease soaked into my clothes than Masu ate in an entire month.
Our meal choices didn’t help us very much. As I mentioned in chapter 1, all of my grandparents developed severe dementia. The last years of their lives were miserable. So what’s the difference between Fargo and Okinawa? Or, for that matter, between Illinois, Iowa, or Kentucky, on the one hand, and Loma Linda or Ikaria, Greece, on the other? Is it just a question of food? Certainly we eat differently. But you have to wonder if some of the credit for the good health people enjoy in the blue zones should go to clean air or genetics.
Researchers at Loma Linda University wondered, too. And they decided to find out. They invited people to join a study and put them into groups of four. Everyone lived in more or less the same area. But each group included one person following a vegetarian diet, one following a vegan diet (no animal products at all), and two people on typical American diets. In all, 272 people were part of the study. And then the researchers just sat back and waited.
What happened next was striking—and it did not say much for California air. Even though everyone lived in the same community, breathed the same air, and had more or less similar genetic risks, those who skipped meat were only one-third as likely to develop Alzheimer’s disease compared with those who routinely ate meat.1 Chalk one up for food. While other aspects of a healthy lifestyle are important, as we’ll see shortly, it looks like food choices weigh in big.
In the last chapter, we saw how Chicago researchers had identified copper as a suspect in cognitive decline. The blame, it seems, goes to copper’s tendency to accumulate in plaques and produce free radicals that can damage cells. But copper’s dangers seemed to depend, oddly enough, on how much fat people were eating. That is, people whose diets included a lot of copper, along with a good dose of saturated fat or partially hydrogenated oils, were much more likely to lose their mental faculties over time. Those who generally avoided these fats were more likely to stay sharp—regardless of how much copper was in their diets. Copper seemed to be dangerous only when the diet also held a fair amount of saturated fat.
You’ve seen saturated fat. It is what makes up the white streaks marbling through a chunk of bacon or steak. It is what makes whole milk creamy and cheese waxy. Its name comes from the fact that the fat molecule—if you could look at it under a powerful microscope—is completely covered with hydrogen atoms. That is, it is saturated with them. But you don’t need to be a chemist to spot saturated fat. At room temperature, it is solid. So lard and cheese are obviously loaded with it, while corn oil and olive oil, which are easily pourable, are not.
In the American diet, the biggest source of saturated fat is from dairy products—cheese, ice cream, butter, and milk. Meats—chicken, sausage, burgers, and roast beef—are a close second.2
So copper plus bad fats equals a higher risk of brain problems. However, the Chicago researchers found that saturated fat is apparently harmful all by itself. Over a four-year period, people who got around 25 grams of saturated fat each day had at least twice the risk of developing Alzheimer’s disease compared with those who got only about half that much.3 Typical vegetable oils had the opposite effect, reducing the risk of Alzheimer’s.
The other “bad” fat is partially hydrogenated oil, sometimes called trans fat. It is produced by a process called hydrogenation, which food manufacturers use to turn liquid oils into solid fats. With a buttery mouthfeel and a long shelf life, these artificial fats are packed into pastries, snack foods, and french fries. Unfortunately, they don’t extend your shelf life. The Chicago research team found that people consuming the most partially hydrogenated oils had more than double the risk of Alzheimer’s compared with people who generally avoid these fats.3
Similar findings turned up in New York, where Columbia University researchers tracked 908 elderly New Yorkers. All were free of Alzheimer’s disease when the study began. But over the next four years, those who ate the most calories and fat were more than twice as likely to develop Alzheimer’s compared with those who ate more modestly.4 The New York team then brought more volunteers into the study, and much the same pattern held. Those who tended to favor meat and dairy products had a higher risk of developing Alzheimer’s disease compared with those who chose what the researchers called a “Mediterranean” pattern of more healthful foods.5 In both the Chicago and the New York studies, people who had fewer “bad” fats in their diets had less risk, and this was true even if they had APOE e4 allele.
A study in Finland came up with much the same result: Saturated fat increased the risk of dementia in people with APOE e4 allele.6 A Dutch study broke from the pattern, suggesting that diet mattered in the first few years of observation but not after that, for reasons that are not clear.7 Overall, the jury says that something about the fat in meat and dairy products poses a problem for the brain.
So it looks like these “bad” fats are linked to Alzheimer’s disease, and teaming up with copper makes things all the worse.
Compare the Saturated Fat Content
| It makes sense to take advantage of foods from plant sources. With few exceptions, foods from plant sources are strikingly low in saturated fat. | |||
| HIGH-FAT (IN GRAMS) | LOW-FAT (IN GRAMS) | ||
| Beef, ground (3 oz.) | 5.6 | Apple (1 medium) | 0.1 |
| Cashews (1 oz.) | 2.2 | Banana (1 medium) | 0.1 |
| Cheese, cheddar (1 oz.) | 6.0 | Beans, pinto (½ cup) | 0.2 |
| Cheese, mozzarella (1 oz.) | 3.7 | Broccoli (1 cup) | 0.1 |
| Chicken breast (½ breast, roasted) | 2.1 | Chickpeas (½ cup) Orange (1 large) | 0.0 |
| Egg (1 large) | 1.6 | Potato (1 medium) | 0.1 |
| Milk, whole (1 cup) | 4.6 | Rice, brown (1 cup) | 0.3 |
| Salmon, Atlantic (3 oz.) | 2.1 | ||
Saturated fat, trans fats—is some of this sounding familiar? If so, it is because these same “bad” fats assault the heart. Saturated fats and partially hydrogenated oils cause your body to make more cholesterol, which, in turn, encourages plaques to form in the arteries to your heart and to your brain—plaques that gradually pinch off the passage of blood.
If these “bad” fats are a regular part of your diet, your cholesterol level is likely to rise. And studies show that people with high cholesterol levels are more likely to develop Alzheimer’s. Compared with a person whose cholesterol level is under 200 milligrams per deciliter, if your cholesterol is around 220, you are not just courting a heart attack. Your Alzheimer’s risk is higher, too—about 25 percent higher. And if your cholesterol is in the 250 range or higher, your likelihood of developing Alzheimer’s would be about 50 percent higher.8 These numbers come from a study of 9,844 Kaiser Permanente subscribers in California who had their cholesterols checked when they were in their early forties. A high cholesterol level in midlife predicted their Alzheimer’s risk twenty to thirty years later.
It had once been thought that cholesterol in the bloodstream had nothing to do with cholesterol in the brain;9 the brain actually makes its own cholesterol. But researchers now believe the situation is not so simple. They are teasing apart the reasons why fat and cholesterol that cause heart problems are linked to brain problems, too.
The field of Alzheimer’s disease research sometimes feels like a huge jigsaw puzzle where pieces are starting to fit together, even while many gaps remain. Here are some of the pieces researchers are linking together:
Suddenly the puzzle is starting to make sense. Toxic fats cause your body to make cholesterol. And cholesterol, carried by the apoE protein, encourages the production of the beta-amyloid that is so hard on your brain cells. Metals aggravate this process, as we saw in the last chapter, with zinc causing the beta-amyloid to clump together and copper and iron making free radicals that destroy our brain cells. And bit by bit, the neuronal connections that recorded your grandchildren’s names, what you did yesterday, and what you ate for breakfast start to go haywire.
As biological explanations like this begin to take shape, researchers protest that the jigsaw puzzle is by no means complete, and they are right. Even so, the message that emerges is strikingly optimistic. Let’s say you have the APOE e4 gene, which busily makes proteins that are eager to escort cholesterol around your body, like so many shopping carts waiting at the meat counter. Presumably you’re at risk. Well, what if you were to change your diet? What if you were to bypass the meat counter altogether and favor vegetables, fruits, whole grains, and beans instead? Your body would make less cholesterol, your absorption of metals would diminish, and your risk would fall. Means of protecting ourselves are starting to become clear, even if genes would otherwise be working against us.3,4,11
Could it really be that simple? Could toxic fats really push us toward Alzheimer’s disease, and could avoiding them make a difference? Well, first, let’s understand the numbers. What would it take to get to the amount that turned out to be particularly dangerous in the Chicago study—that is, 25 grams of saturated fat?
It is surprisingly easy. Dairy products, meat, and eggs are loaded with it. So if you had just one egg with bacon for breakfast, a grilled cheese sandwich for lunch, and a moderate serving of meat for dinner, they would add up to 25 grams of “bad” fat.
Or have a glass of milk for breakfast, a serving of salmon for lunch, and half a cheese pizza for dinner. Bingo. You’re already at 25 grams of saturated fat.
“Yikes!” I hear you say. “That’s the way most people eat!” True enough. The North Dakota breakfasts I grew up on are not looking so good. We had an egg or two every morning, sometimes with bacon or sausage. We never used butter, but we topped our toast with margarine made from partially hydrogenated fat. We poured milk on our cereal and had another glass of milk on the side. My parents led the way, thinking they were providing nutritious meals for themselves and their children.
Sometimes I wonder what would have happened if my grandfather had not raised cattle for a living. It sounds silly to even raise the question, but what if, instead of living on beef, chicken, and milk, our family’s staples had been like those in Loma Linda or Okinawa or Sardinia, or any of the other places where people live long, healthy lives? Could the long, slow mental decline that preceded my grandparents’ deaths have been prevented?
There is no way of telling for sure. But the good news is that there are plenty of healthful foods that we can take advantage of today. Vegetables, fruits, beans, and grains have essentially no “bad” fats at all. So maybe you’d like Masu’s sweet potatoes, rice, and green vegetables, or Ellsworth’s baked beans, corn on the cob, and soy yogurt. But how about paging through the recipe section of this book, where you’ll find Spiced Pumpkin Bread and Blueberry Buckwheat Pancakes for breakfast, Creamy Pumpkin Bisque, Easy Colorful Pasta Salad, Sweet Potato Burritos, or White Bean Chili for lunch, followed by Red Lentil or Potato Leek Soup, and Baked Ziti or Risotto Primavera for dinner, with a nice Warm Apple Cherry Compote, Baked Apples, or Chocolate Pudding for dessert? The choices are endless.
If the main sources of saturated fat are dairy products and meats, you may be asking, how much meat and dairy products do we actually need?
The answer is, none at all. The healthiest diets exclude animal products completely. I must admit I was slow to come to this realization, which I will blame on my Midwestern upbringing. But studies show that people who choose the veggie burger over the meat variety and top their spaghetti with chunky tomatoes, fresh basil, and asparagus tips instead of meat and cheese get an enormous return on their investment. They are healthier. People who make this change, even late in life, find that excess weight trims away, artery blockages begin to reverse, diabetes improves and sometimes even disappears, blood pressure comes back toward where it ought to be, and their brain cells breathe a huge sigh of relief.
For many people this feels like a tall order. But we have found a way to give you a no-risk test-drive of a 100 percent healthy diet. You’ll see it in chapter 9.
As we have seen, saturated fat and partially hydrogenated oils are really quite unhelpful. But not all fats are so ill-bred. Some are actually good for you. Here’s the reason:
Every cell in your body is surrounded by a cell membrane. This membrane has three layers—two protein layers with a layer of fat sandwiched in between.
If you were to take a close look at this membrane, that fatty middle layer might look unimportant. But it determines a great deal about how the cell works. Imagine that the engine in your car has new, fine motor oil coursing through its moving parts. Everything works great. Now, what if that oil were replaced by thick, black tar? Nothing would work right. Well, the type of fat that is in your cell membranes affects how they work, too. If your cell membranes have “good” fats, they tend to stay healthy.
In 2003, French researchers sampled red blood cells of 246 older people, finding that those whose cell membranes were rich in a certain type of fats, called omega-3 fats, were more likely to maintain their cognitive functions compared with other people.13 An earlier study had shown a similar result: A high level of omega-3s in people’s blood seemed to protect against cognitive decline and Alzheimer’s disease, at least to a degree.14
Not every study has shown this benefit,15 but overall, evidence suggests that having “good” fats in your cell membranes may be helpful. So what are they and how do you get them there?
Let’s start by taking a look at a sprig of broccoli. As you look at it, you can see that it doesn’t have very much fat, of course. But it actually does have some, surprisingly enough. And there is one particular fat hidden there that your body needs. It is an omega-3 fat called ALA, or alpha-linolenic acid.
Putting that ALA molecule under a powerful microscope, we see that it is actually a chain of eighteen carbon atoms joined together. If you were to swallow a bit of broccoli, these healthy fat molecules would pass into your bloodstream. Your body would then lengthen the molecular chain from eighteen carbons to twenty, making a new fat called EPA (eicosapentaenoic acid). You would then tack on two more carbons to make the 22-carbon DHA (docosahexaenoic acid). And it is DHA that the brain needs. So it all starts with ALA, the basic “good” fat in food, and you end up with DHA for your brain.
Now, broccoli is just an example. There are traces of ALA in many vegetables, fruits, and beans, and much larger amounts in other foods, especially walnuts, seeds, flax and flax oil, and canola oil. With these foods in your diet, you’ll have the raw material for building the fats your brain can use.
But there’s a complication here. In order to elongate ALA from eighteen carbons to twenty and eventually to twenty-two carbons—that is, in order to make the fats the brain is looking for—ALA depends on enzymes. Enzymes are the factory workers that take the ALA chain and bolt on the extra carbons to deliver DHA to your brain. And like factory workers everywhere, they can only do so much.
There are certain other fats—called omega-6s—that are just as eager to have extra carbons bolted into place. They tie up the enzymes you need to handle your omega-3s. Omega-6 fats are found in certain cooking oils—safflower oil, sunflower oil, corn oil, cottonseed oil, soybean oil, and grapeseed oil. And there is a whole lot more omega-6 fat in a bottle of any one of these oils than there is omega-3 in broccoli or any other green vegetable. So if you are slathering these oils all over your foods, they slip into your bloodstream and occupy the enzymes that should be handling ALA.16 And suddenly your brain is wondering what happened to the “good” fats it needs.
Now, you do need a little bit of omega-6. But most people’s diets include so much of these oils that they crowd out everything else. Their enzymes are all tied up, and only a fraction of their ALA is ever converted to the longer-chain forms.
So, omega-3s are good, and if you have too much omega-6, it will crowd out your omega-3s. What should you do?
The first step is to have ALA-rich foods in your diet. Have plenty of vegetables, fruits, and beans, and, if you like, top your salad with slivered walnuts or ground flaxseed, for example.
The second step is to greatly limit competing fats. Take a look at the low-fat cooking techniques described in chapter 9 and in the recipe section. You’ll be able to sauté onions and garlic without drowning them in grease. And you’ll be able to top a salad with lighter, healthier dressings.
You already want to avoid animal fat and partially hydrogenated oils because of the harm they do. Limiting or avoiding cooking oils is a good idea, too.
It’s really a question of balance—getting an adequate amount of ALA while limiting the competing oils. The balance your body is looking for is somewhere around 2:1 to 4:1—that is, 2 to 4 grams of omega-6 for every gram of omega-3.16 That is the ratio that maximizes your body’s ability to use the omega-3 to build the longer-chain fats your brain uses. If your menu emphasizes vegetables, fruits, and beans, your foods would give you a pretty good balance of fats naturally. While these healthful foods don’t have a great deal of any sort of fat, what they do have is proportionately rich in omega-3s, as opposed to other kinds of fat.
Some people take a third step, which is to make sure they have DHA in their diets. Their rationale is that for most people very little ALA is actually lengthened to EPA and DHA, so they aim to get DHA directly. Their problem, of course, may be that they are getting too much omega-6, and it is tying up their conversion enzymes. So cutting out those competing oils is important. Still, if you do decide to include DHA in your diet, the most healthful source is a DHA supplement, which you will find at any health food store. Vegan brands are preferable. Their DHA is derived from algae rather than from fish, and they contain no animal-derived ingredients.
That said, omega-3 supplements have not yet proved their worth for preventing dementia. In a two-year English study, 867 elderly people were given a capsule that contained two different omega-3s: 200 milligrams of EPA plus 500 milligrams of DHA. It did nothing to forestall memory loss. The participants’ reaction time, spatial memory, and processing speed were no better than for people given a placebo.17 A Dutch study showed the same result.18 It may be that omega-3 supplements would show more benefit in people who had low omega-3 intake to start with.
Fish oil supplements have also been tested in people who have Alzheimer’s disease to see if they can slow the disease process. So far, results are disappointing. An eighteen-month test of fish oil (2 grams of DHA) in Alzheimer’s patients showed no benefit.19
The take-home message is not to rely on pills. Instead, put omega-3-rich foods on your daily menu.
Some people take a different approach, choosing foods with more vegetable oils than I have been suggesting and adding fish to their diets. Indeed, compared with beef fat or chicken fat, vegetable oils and fish oils have less saturated fat, and fish has more omega-3 fatty acids. In the Chicago study, people who favored vegetable oils and fish had a reduced risk of dementia compared with people who focused on meatier fare, and several other studies have shown much the same thing.20,21
However, a serving of fish is much more like beef than it is like broccoli. As a group, people who eat fish have more weight problems and have a higher risk of diabetes compared with people who skip animal products altogether.22 And excess body weight and diabetes can both put you at higher risk for Alzheimer’s disease. So, if you are already following a healthful plant-based diet, fish is really a step backward.
Part of the problem is that many fish species are fatty. Atlantic salmon, for example, is about 40 percent fat. Chinook salmon is around 50 percent.
“But it’s good fat,” you say. Well, yes, some of it is. But fish fat is always a mixture. About 15 to 30 percent of the fat in fish is omega-3, depending on which species you buy. The other 70 to 85 percent is not “good” fat. It is just a blend of saturated and various unsaturated fats. And every last fat gram packs 9 calories, which is why fatty fish can easily add to your waistline.
Fish also contains cholesterol, just as other animal products do. Some—particularly shellfish like shrimp and lobster—have more cholesterol than red meat. That, plus the methylmercury and other pollutants found in many species (such as tuna), makes fish a less-than-attractive choice. There are other sources of omega-3s that are much more healthful.
It may be that the “benefits” of fish seen in some studies are simply a compensation for the harm of red meat. In other words, fish’s anti-inflammatory or anticoagulant tendencies counteract the opposite tendencies of other meats.23
Not surprisingly, in the blue zones, fish is not a large part of the diet—not even in Okinawa or Sardinia. The diet staples come from plant sources.
Some people promote a “Mediterranean diet,” meaning one that emphasizes vegetables, fruits, beans, and pasta, fish rather than red meat, olive oil instead of butter, and perhaps wine. It’s an easy sell. To North Americans, the word “Mediterranean” conjures up sunny images of places they would rather be.
Earlier I mentioned a Columbia University study in which researchers rated the diets of New Yorkers. Those who emphasized vegetables, fruits, legumes, grains, and fish, while having less meat and dairy products, along with mild to moderate alcohol consumption, cut the risk of developing Alzheimer’s disease over the next five years by 32 to 40 percent.5
The same sort of diet pattern made less difference in a French study.24 Researchers tracked the health of 1,410 people in Bordeaux, finding that this sort of dietary pattern did not reduce the risk of Alzheimer’s disease or other kinds of dementia over the five-year study, although it did seem to slow decline in some cognitive tests.
For most of us, a “Mediterranean diet” pattern is a change in the right direction. It certainly beats the kind of diet I grew up with, and that may be true for you, too. But my assessment is that we can do better. In the same way that people following chicken- or fish-based diets do not do as well as people who avoid meats altogether when it comes to their weight, their diabetes risk, or their heart health, the same is very likely true for brain health as well.
So I would suggest taking the best of the Mediterranean pattern—the vegetables, fruits, beans, and grains—and skipping the fish and oil. We’ll talk about alcohol in the next chapter.
Avoiding fatty foods and emphasizing healthful plant-based meals brings you a couple of added benefits:
Trimming your waistline. People who eat plant-based diets are, as a group, much slimmer than people who eat animal products, including fish. Part of the credit goes to the fiber in vegetables, fruits, beans, and whole grains. Fiber satisfies your appetite with essentially no calories. In addition, plant-based diets also tend to slightly increase your metabolism in the after-meal period.25 As a result, you’ll discover that, even though you have not been counting calories or limiting carbohydrates—and even without adding exercise to your routine—a plant-based diet makes it a lot easier to fit into your jeans.25,26,27
In turn, that slimmer figure means you’ll have less risk of developing diabetes, heart problems, or high blood pressure. And slimmer people also have less risk of Alzheimer’s disease.28
If you are wondering if your weight is in the healthy range, you can check your body mass index. The BMI is a way of looking at your weight while adjusting for your height. This is important because 140 pounds is a healthy weight if you are five foot seven, but not at all if you are six foot five. You’ll find an easy online BMI calculator at www.nhlbisupport.com/bmi/. A healthful BMI is between 18.5 and 25 kg/m2.
If you have some weight to lose, let me encourage you not to bother with a typical calorie-restricted weight-loss diet. Instead, fill up on vegetables, fruits, whole grains, and legumes, and skip animal products and oily foods, and your weight will adjust itself much more easily. See chapter 9.
Lowering your blood pressure. As you know, diet changes can lower blood pressure. The first step most people try is to reduce salt, which is smart, but usually only modestly effective. A much more powerful step is to avoid fatty foods, especially animal products.29 This reduces the viscosity (thickness) of your blood, so it is less like grease and more like water. That means your blood flows more easily and your heart does not have to work so hard to push blood along. Your blood pressure promptly falls.
And there’s more: Fruits and vegetables are rich in potassium, which tends to reduce blood pressure as well. And the weight loss you are enjoying will help bring your pressure down, too.
Together, these steps can have an enormous effect. In chapter 9, I’ll show the best way to put all these things together. It’s easier than you might guess.
Checking your blood pressure, your health-care provider records two numbers (e.g., 120/80). Here is what they mean:
A blood pressure below 120/80 is considered normal. A pressure between 120/80 and 140/90 is called prehypertension, and higher values are called hypertension.
So far, we have mostly focused on things to avoid—toxic metals and “bad” fats in particular. But there are certain nutrients that you want to be sure to include in your regular diet—four vitamins that protect your health, including your brain function. In the following chapter, we’ll see how they work and where to find them.