How Not to Die

  To prevent childhood diabetes, we need to prevent childhood obesity. How do we do that?

  In 2010, the chair of the nutrition department at Loma Linda University published a paper suggesting that giving up meat entirely is an effective way to combat childhood obesity, pointing to population studies demonstrating that people eating plant-based diets are consistently thinner than those who eat meat.28

  To study body weight, we usually rely on body mass index (BMI), which is a measure of weight that also takes height into account. For adults, a BMI over 30 is considered obese. Between 25 and 29.9 is considered overweight, and a BMI between 18.5 and 24.9 is considered “ideal weight.” In the medical profession, we used to call a BMI of under 25 “normal weight.” Sadly, that’s no longer normal.

  What’s your BMI? Visit one of the scores of online BMI calculators or grab a calculator and multiply your weight in pounds by 703. Then divide that twice by your height in inches. For example, if you weigh 200 pounds and are 71 inches tall (five foot eleven), that would be (200 × 703) ÷ 71 ÷ 71 = 27.9, a BMI indicating that you would be, unfortunately, significantly overweight.

  The largest study ever to compare the obesity rates of those eating plant-based diets was published in North America. Meat eaters topped the charts with an average BMI of 28.8—close to being obese. Flexitarians (people who ate meat more on a weekly basis rather than daily) did better at a BMI of 27.3, but were still overweight. With a BMI of 26.3, pesco-vegetarians (people who avoid all meat except fish) did better still. Even U.S. vegetarians tend to be marginally overweight, coming in at 25.7. The only dietary group found to be of ideal weight were the vegans, whose BMI averaged 23.6.29

  So why aren’t more parents feeding their kids plant-based diets? There’s a common misconception in America that their growth will be stunted. However, the opposite may be true. Loma Linda University researchers found that children who eat vegetarian diets not only grow up leaner than kids who eat meat but taller, too, by about an inch.30 In contrast, meat intake is associated more with horizontal growth: The same researchers found a strong link between consumption of animal foods and increased risk of being overweight.31

  Developing diabetes in childhood appears to cut life expectancy by about twenty years.32 Who among us wouldn’t go to the ends of the earth to enable our kids to live two decades longer?

  The Fat You Eat and the Fat You Wear

  Carrying excess body fat is the number-one risk factor for type 2 diabetes; up to 90 percent of those who develop the disease are overweight.33 What’s the connection? In part, a phenomenon known as the spillover effect.

  Interestingly, the number of individual fat cells in your body doesn’t change much in adulthood, no matter how much weight you gain or lose. They just swell up with fat as the body gains weight, so when your belly gets bigger, you’re not necessarily creating new fat cells; rather, you’re just cramming more fat into existing ones.34 In overweight and obese people, these cells can get so bloated that they actually spill fat back into the bloodstream, potentially causing the same clogging of insulin signaling one would experience from eating a fatty meal.

  Doctors can actually measure the level of freely floating fat in the bloodstream. Normally, it’s between about one hundred and five hundred micromoles per liter. But people who are obese have blood levels between roughly six hundred and eight hundred. People eating low-carb, high-fat diets can reach the same elevated levels. Even a trim person eating a high-fat diet can average eight hundred, so that sky-high number isn’t exclusive to obese patients. Because those eating high-fat diets are absorbing so much fat into their bloodstreams from their digestive tract, the level of free fat in their blood is as high as someone who’s grossly obese.35

  Similarly, being obese can be like gorging on bacon and butter all day even if you are actually eating healthfully. That’s because an obese person’s body may be constantly spilling fat into the bloodstream, regardless of what goes into the mouth. No matter the source of fat in your blood, as fat levels rise, your ability to clear sugar from the blood drops due to insulin resistance—the cause of type 2 diabetes.

  People who eat a plant-based diet, on the other hand, have just a small fraction of the rate of diabetes seen in those who regularly eat meat. As you can see in figure 1, as diets become increasingly plant based, there appears to be a stepped drop in diabetes rates.36 Based on a study of eighty-nine thousand Californians, flexitarians appear to cut their rate of diabetes by 28 percent, good news for those who eat meat maybe once a week rather than every day. Those who cut out all meat except fish appear to cut their rates in half. What about those eliminating all meat, including fish? They appear to eliminate 61 percent of their risk. And those who go a step farther and drop eggs and dairy foods too? They may drop their diabetes rates 78 percent compared with people who eat meat on a daily basis.

  Why would this be?

  Is it just because people eating plant-based diets are better able to control their weight? Not entirely. Even at the same weight as regular omnivores, vegans appear to have less than half the risk of diabetes.37 The explanation may lie in the difference between plant fats and animal fats.

  Figure 1

  Saturated Fat and Diabetes

  Not all fats affect our muscle cells in the same way. For example, palmitate, the kind of saturated fat found mostly in meat, dairy, and eggs, causes insulin resistance. On the other hand, oleate, the monounsaturated fat found mostly in nuts, olives, and avocados, may actually protect against the detrimental effects of the saturated fat.38 Saturated fats can wreak all sorts of havoc in muscle cells and may result in the accumulation of more toxic breakdown products (such as ceramide and diacylglycerol)39 and free radicals and can cause inflammation and even mitochondrial dysfunction—that is, interference with the little power plants (mitochondria) within our cells.40 This phenomenon is known as lipotoxicity (lipo meaning fat, as in liposuction).41 If we take muscle biopsies from people, saturated fat buildup in the membranes of their muscle cells correlates with insulin resistance.42 Monounsaturated fats, however, are more likely to be detoxified by the body or safely stored away.43

  This discrepancy may explain why individuals eating plant-based diets are better protected from diabetes. Researchers have compared the insulin resistance and muscle-fat content of vegans versus omnivores. Because people eating plant-based diets have the advantage of being so much slimmer on average, the researchers recruited omnivores who weighed the same as the vegans they were studying so that they could see whether plant-based diets had a direct effect beyond the indirect benefit of pulling fat out of the muscles by helping people to lose weight.

  The result? There was significantly less fat trapped in the deep calf muscles of vegans than in those of comparably slim omnivores.44 Those eating plant-based diets have been found to have better insulin sensitivity, better blood sugar levels, better insulin levels,45 and even significantly improved function of their beta cells—the cells in the pancreas that produce insulin in the first place.46

  In other words, people eating plant-based diets appear to be better at both producing and using insulin.

  Preventing Diabetes by Eating More

  Many population studies have shown that people who eat significant amounts of legumes (e.g., beans, split peas, chickpeas, and lentils) tend to weigh less. They also have slimmer waists, less obesity, and lower blood pressure compared to people who don’t eat many legumes.47 But couldn’t these benefits be due not to the legumes themselves but to the fact that people who eat more legumes may eat a healthier diet in general? To tease out the connection, researchers used the most powerful tool in nutrition research: the interventional trial. Instead of just observing what people eat, you change their diets to see what happens. In this case, they put legumes to the test by comparing extra legume consumption head-to-head against calorie restriction.

  Reducing belly fat may be the best way to prevent prediabetes from turning into full-blown diabetes. Though calorie cuttin
g has been the cornerstone of most weight-loss strategies, evidence suggests that the majority of individuals who lose weight by portion control eventually regain it. Starving ourselves almost never works long term. So wouldn’t it be great if instead we could find a way to eat more food to get the same weight-loss benefit?

  The researchers divided overweight subjects into two groups. The first group was asked to eat one kilogram a week of lentils, chickpeas, split peas, or haricot beans—but not to change their diets in any other way. The second group was asked to simply cut out five hundred calories a day from their diets. Guess who got healthier? The group directed to eat more food. Eating legumes was shown to be just as effective at slimming waistlines and improving blood sugar control as calorie cutting. The legume group also gained additional benefits in the form of improved cholesterol and insulin regulation.48 This is encouraging news for overweight individuals at risk of type 2 diabetes. Instead of just eating smaller portions and reducing the quantity of the food they eat, they can also improve the quality of their food by eating legume-rich meals.

  Saturated fats may also be toxic to the cells in the pancreas that produce insulin. At around age twenty, the body stops making new insulin-producing beta cells. After that, if they are lost, they may be lost for good.49 Autopsy studies have shown that by the time type 2 diabetes is diagnosed later in life, you may have already killed off half your beta cells.50

  The toxicity of saturated fats can be demonstrated directly. If we expose beta cells to saturated fat51 or to LDL (“bad”) cholesterol in a petri dish, the beta cells begin to die.52 The same effect is not observed with the monounsaturated fats concentrated in fatty plant foods, such as nuts.53 When you eat saturated fat, both insulin action and insulin secretion are impaired within hours.54 The more saturated fat you have in your blood, the higher your risk may be for developing type 2 diabetes.55

  Of course, just as everyone who smokes doesn’t develop lung cancer, everyone who eats excessive saturated fat doesn’t develop diabetes. There is a genetic component. But for those who already have a genetic predisposition, a diet with too many calories and rich in saturated fat is considered a cause of type 2 diabetes.56

  Losing Weight with a Plant-Based Diet

  As noted earlier, even if you don’t eat extra fat, the extra fat you wear may cause the spillover effect—the tendency for overstretched fat cells to spill fat into the bloodstream. The advantage of a whole-food, plant-based approach to weight loss is that there may be no need for portion control, skipping meals, or counting calories, because most plant foods are naturally nutrient dense and low in calories.

  Figure 2

  Fruits and vegetables, on average, contain about 80–90 percent water. Just as fibre can bulk up the volume of foods without adding calories, so can water. Experiments have shown that people tend to eat the same amount of food at a meal, regardless of calorie count—probably because stretch receptors in the stomach send signals to the brain after a certain volume of food has been ingested. When much of that volume is a zero-calorie component like fibre or water, that means you can eat more food but gain less weight.57

  Figure 2 shows the amounts of broccoli, tomatoes, and strawberries that contain one hundred calories, compared with the quantities of one hundred calories of chicken, cheese, and fish. You’ll notice that even though the calorie content is the same, the volume of these foods is different. So it makes sense that one hundred calories of the plants would be more likely to fill you up, while the same one hundred calories from animal or processed foods may leave you half-empty.

  That’s why whole-food, plant-based diets are great for people who like to eat, since you can basically eat as much as you want without worrying about counting calories.

  A head-to-head randomized clinical trial found that a plant-based diet beat the American Diabetes Association’s recommended diet for weight loss. This occurred without restricting portions the subjects ate and without requiring calorie or carb counting.58 Moreover, a review of similar studies found that, in addition to weight loss, individuals consuming plant-based meals experienced improved blood sugar control as well as reduced risk of cardiovascular disease compared with people who followed diets that included more animal products.59 Such are the benefits of a plant-based diet.

  Diabetics are more likely to suffer from strokes and heart failure.60 In fact, diabetic patients without a history of coronary heart disease may have the same risk of heart attack as nondiabetic individuals with confirmed heart disease.61 In addition to improving insulin sensitivity better than conventional diabetic diets, the plant-based approach can also lead to a significant drop in LDL cholesterol, thereby reducing risk of the number-one killer of diabetics, heart disease.62 But how do people feel about making such a major shift in their diets? As Dr. Dean Ornish has quipped, are we all going to live longer, or is it just going to seem longer?63

  Apparently, most people who switch to a plant-based diet are happy they did. One of the reasons there’s been such great compliance with plant-based dietary interventions is that people not only tend to get measurably better, they also tend to feel much better. In a recent randomized, clinical weight-loss trial, diabetics were split into two groups. Half were put on the conventional diabetic diet as recommended by diabetes organizations; the other half were prescribed a plant-based diet consisting mostly of vegetables, grains, legumes, fruits, and nuts. At the end of six months, the plant-based group reported both a significantly better quality of life and significantly higher mood scores than those assigned to the conventional diet. Patients consuming the plant-based diet also felt less constrained than those consuming the conventional diet. Moreover, disinhibition decreased, meaning patients eating vegetarian food were less likely to binge, and the plant-based folks tended to feel less hungry as well—both of which could help these subjects sustain this way of eating in the long run.64 So not only do plant-based diets appear to work better but they may be easier to adopt long term. And with the improvement in mood they seem to bring, there may be benefits for both physical and mental health. (See chapter 12 for more on this topic.)

  When it comes to maximally lowering diabetes risk, does it matter if you eat just a little meat? Researchers in Taiwan sought to answer that question. Traditionally, Asian populations have enjoyed very low rates of diabetes. In recent years, however, diabetes has emerged on a near-epidemic scale, coinciding with the Westernization of Asian diets. Rather than compare vegetarians to modern-day omnivores, these researchers compared vegetarians to those eating a traditional Asian diet, which customarily included very little fish and other meat. The women ate the equivalent of just a single serving of meat each week, while the men had a serving every few days.65

  Both the vegetarian and traditional Asian diet groups were following healthy diets, avoiding fizzy drinks, for example. Despite the similarities in diet among the four thousand study subjects and after accounting for weight, family history, exercise, and smoking, the researchers found that the vegetarian men had only half the odds of diabetes as the occasional meat eaters. The vegetarian women had 75 percent lower odds of diabetes. Those who avoided meat altogether appeared to have significantly lower risk of both prediabetes and diabetes than those who ate plant-based diets with an occasional serving of meat, including fish. The researchers were unable to compare the diabetes rates of the more than one thousand vegetarians in the study to the sixty-nine vegans in the group, however, because the prevalence of diabetes among those eating strictly plant-based was zero.66

  Diabetes-Promoting Pollutants

  The dramatic rise in obesity has been blamed squarely on overeating and inactivity. But could there be something else about the food we’re eating that’s plumping us up? Scientists have begun identifying “obesogenic” chemical pollutants released into the environment that may disrupt your metabolism and predispose you to obesity. Contaminated food is the main source of exposure to these chemicals, and 95 percent of that exposure may come through the consumption of ani
mal fat.67 What’s the big deal? A nationwide study found that people with the highest levels of pollutants in their bloodstreams had an astounding thirty-eight times the odds of diabetes.68 Harvard University researchers identified one chemical in particular, hexachlorobenzene, as a potent risk factor for the disease.69

  Where is this toxin found? Apparently, at the supermarkets. In a supermarket survey of a variety of foods, tinned sardines were found to be the most heavily tainted with hexachlorobenzene, though salmon was found to be the most contaminated food overall. Two dozen pesticides were detected in the salmon fillets.70 Farmed salmon may be the worst, containing ten times more of a class of toxic chemicals called PCBs than wild-caught salmon.71

  Industrial toxins like hexachlorobenzene and PCBs were largely banned decades ago. So how could they account for any of our increasing rates of diabetes? The answer to this paradox may be our obesity epidemic. The association between these toxic chemicals and diabetes was much stronger among obese subjects than in lean subjects studied, raising the possibility that your own fat stores are acting as reservoirs for these pollutants.72 Overweight individuals may be effectively carrying around a personal toxic waste dump on their hips. Without significant weight loss, people whose bodies contain salmon pollutants may take between fifty to seventy-five years to clear the chemicals from their bodies.73

  Do those who avoid meat completely get enough nutrients? To find out, researchers looked at a day in the life of thirteen thousand people all across America. They compared the nutrient intake of those who ate meat to those who didn’t. The study found that, calorie for calorie, those eating vegetarian diets were getting higher intakes of nearly every nutrient: more fibre, more vitamin A, more vitamin C, more vitamin E, more of the B vitamins thiamin, riboflavin, and folate, as well as more calcium, magnesium, iron, and potassium. Furthermore, many of the nutrients that are so rich in plant-based diets are among the very ones that most Americans normally don’t get enough of—namely, vitamins A, C, E, not to mention fibre, calcium, magnesium, and potassium. At the same time, people who avoided meat also ingested fewer harmful substances, such as sodium, saturated fat, and cholesterol.74