The major determinant of our long-term health is the nutritional quality of the calories we eat. It is the quality of the fat, the quality of the protein, and the quality of the carbohydrates we eat that most influence our health.
Ask yourself: Is the food I am about to eat a whole, natural plant source of calories? Is it packed with fiber, antioxidants, and phytochemicals? Does it contain not only known nutrients but plenty of undiscovered nutrients too? Or were most of those fragile, but beneficial, nutrients lost in the way the food was processed or prepared? These are even more important questions than whether it is a low-fat or high-fat food.
You may have heard that nuts and seeds are fatty and fattening and are foods to be shunned. However this myth is finally buried. Recent evidence from several studies shows a wide variety of health benefits from eating these foods. There has never been a study that showed any negative health outcomes from consuming these natural, high-fat, whole plant foods. In fact, the studies show only positive health benefits and conclude that these foods should be an important part of a well-rounded, healthy diet. It must be emphasized that health problems associated with high-fat diets are from consuming animal fats, processed oils, and trans fats, not from avocados, raw nuts, or seeds.
As discussed, macronutrients—fat, carbohydrates, and protein—are the three sources of calories. Americans eat too much of all three. I intentionally do not give a preferred percentage of each macronutrient in the diet, and I do not recommend that fat be (exclusively) limited. Trying to micromanage the precise amount of each caloric source misses the most critical issue in human nutrition. The real critical issue in human nutrition is meeting your macronutrient needs without excess, while getting sufficient micronutrients (vitamins, minerals, and phytochemicals—the parts of food that do not contain calories) in the process. There is a broad acceptable range in the macronutrient ratio as long as we are not overeating calories. Certainly if we’re overweight, we want to be more careful and limit consumption of these higher-fat foods. As we have seen, it is easy to overeat high-fat foods, as they are a concentrated source of calories. The goal is to find the right balance. Adhering to a diet that is less than 10 percent of calories from fat is not an appropriate recommendation for ideal health. This too-low percentage of fat results in less-than-ideal health outcomes such as low energy and minimized hormone production. The simple truth is that a healthy diet could be 15 percent of calories from fat or even 30 percent of calories from fat. As long as the diet is rich in micronutrients and does not exceed our daily need for calories, a lower-fat diet has no advantage in the prevention and treatment of disease.
There is no evidence to suggest that a diet of equal calories that is extremely low in fat is an advantage for prevention or treatment of heart disease or any other disease. Studies that compare dietary fat percentages suggest that it is not the fat level, but other more critical qualities, that make the diet more or less beneficial.
I want to be clear that the benefits of a vegetarian or vegetable-based diet are not the result of lowfat intake. Most vegan or vegetarian diets are not ideal because they lack green vegetables. It may seem odd that I am claiming most vegetarian diets are lacking in high-nutrient vegetation, seeds, and nuts—all healthful vegetarian foods—but all too often, that is the case. Achieving an ideal level of phytonutrients and other micronutrients necessitates eating a large amount of green vegetables each day. Any diet that does not contain sufficient vegetables is lacking. When you eat lots of vegetables, especially green vegetables, you meet your body’s need for fiber and micronutrients with very few calories. Then to balance the diet and fill your caloric needs, you can choose an assortment of other foods, preferably ones that are of high nutrient quality. Unlike other people advocating plant-based diets, I recommend more vegetables, fruits, beans, nuts, and seeds and less bread, potato, and rice. The daily addition of one or two ounces of nuts and seeds, which average about 175 calories an ounce, can bring the diet up to 15 to 30 percent of calories from fat. This is important, and I repeat: my recommended diet is eating 15 percent or more calories from fat in the form of healthy, whole foods, not oil.
It might seem logical to restrict higher-fat foods like nuts, seeds, and avocadoes because high-fat foods are higher in calories (fat is 9 calories per gram compared to 4 calories per gram in carbohydrates and protein). Although you should take care not to eat too many calories and to adjust the level of these foods to maintain a slim body, there are lots of good reasons to include at least some of these higher-fat foods in your diet. Accumulating research shows that a diet as low as 10 percent of calories from fat may be too low, even for the overweight, diabetic, or heart disease patient. Judicious use of these higher-fat foods is beneficial for not just heart disease, but for weight loss and diabetes too.
The scientific literature corroborates my clinical experience over the last twenty years as I have cared for thousands of patients with obesity, diabetes, and heart disease. It provides evidence to show that for every calorie from white rice, potato, white bread, or animal products that is removed from the diet and substituted with raw seeds and nuts, there are many health benefits, including:
- Lower blood sugar
- Lower cholesterol
- Lower triglycerides
- Better LDL/HDL ratio
- Better antioxidant status
- Better absorption of phytochemicals from vegetables
- Better diabetic control
- Lower weight
- More effective reversal of heart disease
- Prevention of cardiac arrhythmias in heart patients
- More weight loss, not weight gain
- Better nutritional diversity and satisfaction with fewer calories
- Increased protection against cancer
- Better muscle and bone mass with aging
Nuts and Seeds Protect Against Cardiovascular Death
Raw nuts and seeds are packed with nutrients. They contain lignans, bioflavonoids, minerals, and
other antioxidants that protect the fragile freshness of the fats within and contain plant sterols and proteins that naturally lower cholesterol. Because these foods supply certain fibers, phytochemicals, phytosterols, and bioactive nutrients like polyphenols and arginine that are not found in other foods, they also prevent blood vessel inflammation.
Perhaps one of the most unexpected findings in nutritional epidemiology in the past five years has been that nut consumption offers strong protection against heart disease. Several clinical studies have observed beneficial effects on blood lipids as a result of diets high in nuts (including walnuts, peanuts, almonds, and other nuts). A review of twenty-three intervention trials using nuts and seeds convincingly demonstrated that eating nuts daily decreases total cholesterol and LDL cholesterol. Not only do nuts and seeds lower LDL (bad) cholesterol, but they also raise HDL (good) cholesterol. Interestingly, they can help normalize a dangerous type of LDL molecule—the small, dense LDL particles that are particularly damaging to blood vessels, especially the endothelial cells lining the blood vessels.
Ellagitannins are dietary polyphenols with potent antioxidant and other cancer chemopreventive activities. They are found in berries, nuts, and seeds and are best absorbed from walnuts. Walnuts can reduce C-reactive protein and harmful plaque adhesion molecules, two significant markers of inflammation in arteries. The result is improved, and even restored, endothelial function (which includes the elastic property of arteries to dilate when meeting an increased demand for blood). According to the researchers, walnuts are the first food to show such cardiovascular benefits.
Studies on nuts reveal much more than just their power to change risk factors like blood glucose or cholesterol; they actually show that nuts decrease cardiovascular death and overall increase life span. Five large prospective cohort studies (Adventist Health Study, Iowa Women Health Study, Nurses’ Health Study, Physicians’ Health Study, and CARE Study) have studied the relationship between nut consumption and the risk of atherosclerotic heart disease. All found a strong inverse association. That means nuts are lifesaving.
The protective effect of nut consumption on heart disease is not offset by increased mortality from other causes. In fact, nut consumption has been found to be inversely related to all-cause mortality in all tested populations including whites, blacks, and the elderly. Eating nuts and seeds offers a welldocumented intervention for increasing longevity. The beneficial effects of nut consumption observed in clinical and epidemiologic studies underscores the importance of distinguishing different types of fat. Nuts contain mostly mono- and polyunsaturated fats that lower LDL cholesterol levels. However, the favorable fat issue does not alone account for the health benefits of nuts and seeds. These powerful health benefits are not achieved when oils, rather than whole nuts and seeds, are substituted as a caloric source.
Based on data from the Nurses’ Health Study, it was estimated that substituting fat from one ounce of nuts for equivalent energy from carbohydrates in an average diet was associated with a 30 percent reduction in heart disease risk. The substitution of nut fat for saturated fat was associated with a 45 percent reduction in risk. Frank Hu, M.D., a leading researcher at the Harvard School of Public Health, on the value of nuts in the American diet, says, “Our epidemiological studies have shown eating about one ounce of nuts a day will reduce the risk of heart disease by over 30 percent.” The Physicians’ Health Study added much more to the story. The most fascinating and perhaps most important finding is that nuts and seeds do not just lower cholesterol and protect against heart attacks.
Components of nuts apparently also have antiarrhythmic and antiseizure effects, which dramatically reduce the occurrence of sudden death. These rhythm-stabilizing effects of nuts and seeds are due not only to the amount of omega-3 fatty acids but also to other beneficial qualities of these natural foods.
The Physicians’ Health Study followed 21,454 male participants for an average of seventeen years. Researchers found a lower risk of sudden cardiac death and other coronary heart disease end points after controlling for known cardiac risk factors and other dietary habits. When compared with men who rarely or never consumed seeds or nuts, those who consumed two or more servings per week reduced their risk of sudden cardiac death by over 50 percent. This means that the consumption of nuts powerfully reduces the chance of having a life-threatening cardiac arrhythmia called ventricular fibrillation or ventricular tachycardia. People who have heart disease do not always die of heart attacks; they often die of an irregular heartbeat that prevents the heart from pumping properly.
The absence of nuts and seeds in a diet may actually increase the risk of one of these fatal heart rhythm disturbances. In my years of medical practice, the most common reasons patients have come to see me are high blood pressure, high cholesterol, atherosclerosis, angina, diabetes, and being overweight. People following my nutritional advice have seen dramatic improvements in their conditions. They have lost weight, normalized their blood pressure and cholesterol, and reversed their heart disease and atherosclerosis in an impressive and often dramatic fashion. All my patients were advised to eat some raw nuts and seeds in their diets.