How to Become Smarter (15 page)

My advice is to follow conventional food pyramids most of the time, such as Harvard’s Healthy Eating Plate [
61
] or the USDA’s
MyPlate
. The natural food pyramid, on the other hand, may have some entertainment value for you. There are several advantages that the conventional dietary guidelines have over the diets proposed in this book. First, the conventional food pyramids are not “strange diets” and will not cut into your social life. Second, the official dietary guidelines represent safe and balanced diets and will not cause health problems in the majority of people. Third, a team of experts in the field of nutrition developed these guidelines, and their recommendations are based on the totality of all available scientific evidence.

Every now and then researchers call into question the scientific validity of the food pyramids, and the government responds by revising them. For example, government experts used to say that all dietary fat is bad for health. Nowadays, some food pyramids state that trans-fat and saturated fat are bad fats, whereas unsaturated fat is good for you. The official position of health authorities on dietary fat may change again in the future. Nonetheless, the official guidelines are the
most scientific
dietary advice that you will find at any given point in time. If you ask me what kind of diet is the healthiest
for everyday use
for the majority of people, my response is as follows:

• a diverse diet based on boiled or steamed grains;
  
• it contains all food products listed among “good” and “sedative foods” (see the natural food pyramid);
  
• this diet limits or excludes “problem foods;”
  
• contains normal amounts of protein (about 100 grams or 3 ounces of protein-rich foods in every meal).
  

In my experience, this kind of nutrition causes the least amount of problems in the long run. It is possible to replace all grains with boiled potatoes for extended periods, many months. Based on my experience, the weight and satiety level will not change, but you will feel less bored. Nonetheless, the prolonged exclusion of grains from the diet is not good for mental health. At some point, I get insomnia and become irritable and restless. Raw wheat extract helps, but boiled grains cause a complete return to normalcy. As mentioned earlier, diets based on cooked grains, in my view, tend to promote boredom (along with normalcy) and can be problematic for a person who lives alone. In this case, one or two days a week of the antidepressant diet can be helpful. The antidepressant diet excludes cooked grains, which you can replace temporarily with boiled potatoes.

• Self-experimentation suggests that a raw diet that excludes all artificial ingredients (the “ancestral diet”) improves mental clarity (fluid intelligence) within 2 to 3 days. This diet is not socially acceptable in most cultures and carries a risk of serious infectious disease because of pathogens that can be present in raw meat and fish.
  
• It is possible to design diets that are both safe and have beneficial effects that are similar to those of the ancestral diet.
  
• For example, a safer alternative is a diet that excludes all artificial ingredients (food additives, dietary supplements, and seasonings) and consists of fruits, vegetables (both raw and boiled or steamed), raw water extract of grains, pasteurized low-fat milk or cultured milk, and unprocessed unsalted cheese. This diet is called the “antidepressant diet” in this book.
  
• We can add meat and fish cooked at moderate temperatures and nuts to the antidepressant diet. This change will not reduce mental clarity if the amount of cooked flesh does not exceed the amount of dairy products present in the diet (by weight). In this book, this diet is called the “modified high-protein diet.”
  
• The Paleolithic diet (fruits, vegetables, nuts, cooked meat and cooked fish) can also improve mental abilities and is useful on a short-term basis. It can worsen mood if you stay on this diet for an extended period.
  
• Self-experimentation shows that all of the above diets improve fluid intelligence, judging by the ease of solving many (but not all) of life’s problems that previously seemed difficult. The improvement of mental clarity also manifests itself as ease of learning complex material.
  
• The fruit-and-vegetable diet also can improve fluid intelligence and appears to result in the highest information processing speed. Yet this diet increases distractibility and reduces capacity for work.
  
• It is unnecessary to adhere to any of the above regimens on a permanent basis because even a temporary improvement of mental clarity provides long-term benefits.
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The main source of saturated fat in the human diet is animal products such as meat, butter, and whole milk. As an exception, saturated fat is also present in large amounts in some plant foods such as coconut and coconut oil. Traditionally, health care authorities have said that saturated fat is bad for health. Nonetheless, a number of recent epidemiological studies and dietary experiments have found that the amount of saturated fat in the diet does not have any effect on body weight and the blood cholesterol level [
255
-
259
]. Saturated fat has no effect on the composition of blood lipids, such as the level of “bad” cholesterol. One study shows that consumption of foods rich in saturated fat (red meat, butter, high-fat dairy) correlates
inversely
with the amount of body fat several years later [
260
]. By the way, dietary cholesterol has nothing to do with the blood level of cholesterol. It is the liver that synthesizes most of the cholesterol in your blood [
61
].

Scientists have experimented on mice and rats to obtain most of the research data regarding the presumed deleterious effects of saturated fat. Rodents, however, have the digestive tract and physiology that are different from those of humans. For example, a classic high-fat diet, the ketogenic diet, causes a weight gain in rodents but a weight loss in humans [
119
,
261
]. Many of these experiments on laboratory animals employ unrealistic, preposterous amounts of saturated fat, such as diets containing 80% fat by calories. Therefore, if an experiment on rodents shows that a diet containing elevated amounts of saturated fat causes some health problems, this does not necessarily mean that saturated fat is bad for human health.

Some epidemiological studies found that increased consumption of saturated fat correlates with certain cardiovascular diseases, but others found no such association [
256
]. Note that we are talking about a statistical association or correlation,
not
causation. Few epidemiological studies can offer proof of causation [
36
]; most of them show an association. Only randomized controlled trials can prove causation beyond a doubt. (In references [
37
,
99
], readers can find a list of epidemiology-based lifestyle recommendations that scientists later refuted by randomized controlled trials.) The association of saturated fat with cardiovascular disease in some epidemiological studies, if it is real, can have a number of alternative explanations. For example, a gene may increase dietary preference for saturated fat and at the same time make a person more susceptible to cardiovascular problems through a mechanism unrelated to dietary fats. Alternatively, saturated fat may prevent cancer and this will make the person more likely to die of the other major cause of death: cardiovascular disease. Another possible explanation is that people who have complied with the decades-old recommendation to avoid dietary fat are fundamentally different from those who ignored this recommendation. The compliant people may have engaged in various behaviors that are beneficial to their cardiovascular health. Those behaviors, not the avoidance of saturated fat, have contributed to the better health outcomes. There are other possible explanations. Yet when someone reports that consumption of saturated fat is associated with some unfavorable health outcome, people often jump to the conclusion that it is the saturated fat that causes the bad outcome. In actuality, saturated fat may have nothing to do with the health problem.

My guess is that one can find anything that they want to find in statistical data, with enough time and effort. It is likely that one can find disease associations with
any
types of food, even the holiest of holies of food pyramids: whole grains, fruits, and vegetables. Even with physical exercise [
262
]. (As an aside, one experiment on laboratory rats, which is not an epidemiological study, shows that bread crust can cause weight gain and damage to kidneys [
236
].) If some skilled epidemiologists can show that increased consumption of whole grains, fruits, or vegetables correlates with some unfavorable outcomes, this will demonstrate the shortcomings of epidemiology-based dietary recommendations. After this book came out, I have been able to find several studies of this sort [
873
,
880
,
895
,
897
,
905
,
909
]. As we saw earlier, this statistical association does not imply that whole grains (or fruits and vegetables) indeed cause health problems.

Animals in the wild never remove saturated fat from their food (muscle meat and whole milk). The same is true of ethnic groups who consume a lot of animal products, such Eskimos. They consume animal food as is and do not try to “improve” it by making it low-fat. Calves drink whole milk from a mother cow and predators eat all flesh including fat, muscle, and organs. Some primates consume meat and they too consume whole meat, including fat. Human milk is fattier than whole milk from a cow. How come we do not remove fat from the milk of nursing mothers if saturated fat is such a bad thing for health? Some readers can say that saturated fat is good in infancy and bad for health after infancy. Well, a number of studies have shown that increased consumption of saturated fat
by adults
does not correlate with any negative effects on health [
119
,
255
,
257
,
258
,
263
,
264
]. In addition, saturated fat serves several important functions in the human body [
265
]. Thus, the jury is still out regarding the presumed negative effects of saturated fat.

The kind of fat that
may
have adverse effects on health is fat that underwent cooking at high temperatures, 200-400°C (390-750°F). Some studies have shown that cooking of meat at high temperatures (by frying or grilling) increases the amount of cholesterol oxidation products 5- to 10-fold [
124
,
266
]. Cholesterol oxidation products play a role in the pathogenesis of atherosclerosis, which can lead to a number of cardiovascular problems [
178
,
267
]. Steaming of meat for extended periods (for example, for 30 min) can also increase the amount of cholesterol oxides in cooked meat [
124
,
266
]. At the same time, boiling does not increase the level of cholesterol oxides [
268
]. Therefore, it is possible that there is “good animal fat” and “bad animal fat.” The “bad animal fat” is present in animal products such as grilled meat or fried butter, whereas “good animal fat” is present in boiled meat and pasteurized (uncooked) dairy products. It would be interesting to conduct epidemiological studies on the association of bad and good animal fat with cardiovascular diseases. If an epidemiological study uncovers an association, it will be a good hypothesis to test in randomized controlled trials. One randomized controlled trial shows that food cooked at high temperatures causes pathological changes consistent with the development of diabetes and cardiovascular problems, whereas food cooked at moderate temperatures does not [
830
].

Another common fallacy regarding animal fat and dietary fat in general is as follows. Since low-fat diets can cause weight loss and improve cardiovascular risk factors (they can lower “bad cholesterol” in blood), then it seems logical to make some assumptions about high-fat diets. As the fallacy goes, high-fat diets should have the opposite effects: they should cause a weight gain and worsen cardiovascular risk factors. In actuality, high-fat low-carbohydrate diets (such as Atkins) cause an even faster weight loss and also improve blood cholesterol composition [
119
,
269
-
275
]. As mentioned above, people who consume more animal fat than usual are not overweight, on average [
255
]. These people also do not have an elevated blood cholesterol level.

Experiments on laboratory animals show that addition of sucrose (refined sugar) to the diet of rats increases their blood cholesterol level and body weight [
94
]. These data suggest that “unnatural food” rather than dietary fat is responsible for obesity and cardiovascular problems. On the other hand, natural fats of plant and animal origin do not pose any danger to the health of humans. Health authorities should stop demonizing animal fat.