Foreword

The Health Power of Vegan Foods

foreword by Neal D. Barnard, MD

Whether vegan foods are inspired by Mediterranean, Asian, or any of a hundred other traditions, they boast delightful flavors and aromas. They are animal-friendly and kind to the environment.

But perhaps the broadest appeal of vegan dishes comes from what they do for your health. When you fill your plate with vegetables, fruits, whole grains, and legumes, and skip the cholesterol, fat, and other undesirables that animal products harbor, you've got a menu that is unmatched in health-promoting power.

For decades, researchers have been measuring the health benefits of various diets. One group that has lent itself to intensive study is the Seventh-Day Adventists. Adventist religious tenets call for avoiding tobacco, alcohol, caffeine, and meat. But while most Adventists follow the first three rules pretty well, only about half avoid meat. The rest are modest meat-eaters. That creates a perfect natural experiment, allowing scientists to see the effects of meat-eating in an otherwise health-conscious population.

In 1960, when the Adventist Mortality Study began tracking the health of 24,673 adults, it became clear that vegetarians were much less likely to be overweight compared with people who ate even rather small amounts of meat. The vegetarians in the study were also much less likely to develop diabetes.1

But it was not until four decades later that results for vegans could be teased apart from those of other vegetarians. In the Adventist Health Study 2, which included 60,903 participants, vegans were by far the slimmest group, with a body weight right smack in the middle of the healthy range. Lacto-ovo-vegetarians were a bit heavier, and participants who included fish in their diets were heavier still. "Semi-vegetarians"—those who had meat less than once a week, but more than once per month—weighed more than fish-eaters, and frequent meat-eaters were teetering on the edge of obesity.2

Diabetes risk followed exactly the same gradient, affecting only 2.9 percent of vegans, compared with nearly 8 percent of nonvegetarians, with the other diet groups falling in between.2

Researchers have studied European populations in the same way. In the European Prospective Investigation into Cancer and Nutrition, vegans were once again the slimmest group, red meat–eaters the heaviest, with lacto-ovo-vegetarians and fish-eaters falling in between.3

Because vegan diets have essentially no cholesterol or animal fat, they are powerful cholesterol-lowering diets. At the University of Toronto, David Jenkins, MD, PhD, showed just how powerful. Beginning with a basic vegan diet, he asked volunteers to favor foods with a cholesterol-lowering effect, such as oat bran, nuts, soy products, and certain plant sterols. The combination of a vegan diet paired with cholesterol-lowering foods reduced LDL ("bad") cholesterol by nearly 30 percent in four weeks, which was similar to the power of cholesterol-lowering drugs.4

Studies conducted by the Physicians' Committee for Responsible Medicine (PCRM) show that low-fat vegan diets have similarly dramatic effects. In 2005, PCRM reported the results of a study involving a group of postmenopausal women who had been struggling with weight problems. The volunteers had tried every diet you can imagine, and felt stuck—nothing they did could take the weight off and keep it off. As the study began, we assigned half the participants to a low-fat vegan diet; the other half began a more conventional low-fat diet. By 14 weeks, the difference between the two groups was clear. The vegans had lost, on average, one pound per week, while the control group had lost slightly more than half that amount.5 The PCRM researchers continued to track their weight. While the control group regained its lost weight, the vegan group did not—even after two years of follow-up.6

What was especially remarkable was why the vegan group lost weight. Part of the credit goes to the fact that vegan diets have no animal fat. Since every gram of fat has nine calories (compared with carbohydrates, which have only four), skipping high-fat items means skipping the most calorie-dense foods. Also, foods from plant sources are fiber-rich. Because fiber holds water and fills your stomach, it tricks your brain into thinking you are eating a large amount of food when in fact your calorie intake is modest.

But there is one more compelling reason for this weight loss: Vegan foods boost your metabolism for a few hours after every meal. In the weight-loss study described above, we brought the participants into the laboratory. Using a special mask that fits over the nose and mouth, we were able to measure their metabolism. This is because the amount of oxygen a person takes in and the carbon dioxide he or she breathes out shows how fast the body is burning calories. We did this test before and after a meal.

After the participants had been on a vegan diet for 14 weeks, their after-meal calorie-burn was measurably faster. The effect was modest, but it occurred after every breakfast, lunch, and dinner. More of the calories they consumed were burned off as body heat rather than being stored as fat.

So vegan diets have fewer calories to start with, they satisfy your appetite before you've overdone it, and they ramp up your metabolism for a few hours after every meal.

A Diet Solution For Type 2 Diabetes

Starting in 2003, the National Institutes of Health funded our research team to test a similar diet for diabetes. Among people who kept their medications and exercise constant, a low-fat vegan diet controlled blood sugar much better than a more conventional diabetes diet.7 The vegan diet also lowered participants' cholesterol and helped them lose weight. Many participants were able to reduce their medications or even eliminate them. Tracked over the long run, the benefits of the vegan diet still held.8

Vegan diets have many other advantages, from reducing menstrual cramps and premenstrual syndrome to improving arthritis pain and migraines. All in all, it is a remarkably healthful way to go.

In 2009, the American Dietetic Association reaffirmed its strong support for vegetarian and vegan diets. In its official position paper, the ADA wrote that vegan diets are not just nutritionally adequate; they bring a wide variety of health benefits.9

The Vitamin Gap

Some people may think natural foods ought to provide all nutrition needed for a vegan diet, without having to rely on supplements. I agree, in principle. But we are not in anything like a natural environment. Just as being indoors deprives us of the sunlight that normally produces vitamin D, modern life also means a vitamin B12 supplement is essential for vegans—and a good idea for everyone else, too.

A healthy diet means including a reliable source of vitamin B12 in your routine. Vitamin B12 is essential for the blood and central nervous system. Because vitamin B12 is not made by plants or animals, but by bacteria, and because the best food sources of vitamin B12 are animal products, it can be hard for vegetarians and vegans to get the recommended amount. Nevertheless, a daily multiple vitamin will do the job, providing you with enough vitamin B12, as will fortified foods (e.g., fortified soymilk, cereals, etc.).

Be A Model Vegan

If you are new to a vegan diet, let me offer one piece of advice: be a good example. Watch what you eat. Base your menus on a variety of vegetables, fruits, whole grains, and beans. Potato chips, sodas, and other junk foods may be free of animal products, but if you rely on them to stay away from meat and dairy, the health benefits will be limited. When you stick to a well-balanced vegan diet, your body is an advertisement to the world that veganism is not just an ethical way of eating, but that it is the optimal choice for your waistline and every other part of you.

As you page through the recipes in this book, you can almost taste the healthy power they have. I hope you enjoy them and all the wonderful benefits they bring.

References

1. Snowdon DA, Phillips RL. Does a vegetarian diet reduce the occurrence of diabetes? Am J Publ Health 1985;75:507-12.

2. Tonstad S, et al. Type of vegetarian diet, body weight and prevalence of type 2 diabetes. Diabetes Care 2009;32:791-6.

3. Spencer EA, et al. Diet and body mass index in 38,000 EPIC-Oxford meat-eaters, fish-eaters, vegetarians, and vegans. Int J Obesity 2003;27:728-34.

4. Jenkins DJ, Kendall CW, Marchie A, et al. Direct comparison of a dietary portfolio of cholesterol-lowering foods with a statin in hypercholesterolemic participants. Am J Clin Nutr. 2005;81:380-387.

5. Barnard ND, Scialli AR, Turner-McGrievy G, Lanou AJ, Glass J. The effects of a low-fat, plant-based dietary intervention on body weight, metabolism, and insulin sensitivity. Am J Med 2005;118:991-997.

6. Turner-McGrievy GM, Barnard ND, Scialli AR. A two-year randomized weight loss trial comparing a vegan diet to a more moderate low-fat diet. Obesity 2007;15:2276-81.

7. Barnard ND, Cohen J, Jenkins DJ, Turner-McGrievy G, Gloede L, Jaster B, Seidl K, Green AA, Talpers S. A low-fat, vegan diet improves glycemic control and cardiovascular risk factors in a randomized clinical trial in individuals with type 2 diabetes. Diabetes Care 2006;29:1777-1783.

8. Barnard ND, Cohen J, Jenkins DJ, Turner-McGrievy G, Gloede L, Green A, Ferdowsian H. A low-fat vegan diet and a conventional diabetes diet in the treatment of type 2 diabetes: a randomized, controlled, 74-week clinical trial. Am J Clin Nutr 2009;89(suppl):1588S-96S.

9. American Dietetic Association. Position of the American Dietetic Association : Vegetarian diets. J Am Diet Assoc. 2009;109:1266-82.