Among meats, fish is best, containing both fairly complete proteins and the so called "omega-3" fatty acids (EP A, or eicosapentaenoic acid, and DHA, or docosahexaenoic acid), which appear largely responsible for the low incidence of arteriosclerosis in Eskimos, despite their high fat diet. The fattier fishes contain more of these omega-3 compounds (herring, mullet, anchovies, mackerel, fresh water trout, catfish, smelt, sardines, and salmon) as opposed to fishes of medium fat content (rockfish, sea trout, flounder, ocean perch, halibut, and swordfish) or low fat fishes (cod, haddock, lake perch, sole, whiting, red snapper, and pike). White meat albacore tuna is of medium fat content and contains omegadoses, but in other kinds of canned tuna the fatty acids are apt to have been removed in processing. Shellfish are low in fat but relatively higher in omega 3 fatty acids than other low fat "fishes." While for years shellfish were regarded as a forbidden food for people with high blood cholesterol, their cholesterol content is now known to be far lower than previous studies indicated; the early studies were picking up noncholesterol compounds along with cholesterol. Table 9.2 displays the percent of calories from fat and the amount of omega 3 fatty acids in various fishes.

Among vegetables and legumes the only fairly "complete" protein is soybean. You can achieve protein completeness in a meal by combining legumes (low in the amino acids tryptophan and methionine, but high in lysine and isoleucine) with one of the grains or cereals (high in tryptophan and methionine, but low in lysine and isoleucine). The cruciferous vegetables are a favored food. These include cabbage, broccoli, brussels sprouts, cauliflower, and turnips. They contain unidentified substances that seem to stimulate your immune system and enzyme system, which help protect against cancer causing agents. Carbohydrates should be complex, not simple ones like plain sugar, molasses, or honey, which contain largely empty calories. The complex carbohydrates potatoes, whole wheat bread and cereals, and grains also contain other nutrients such as protein, vitamins, minerals, and fibers. For many years it was assumed (without actual testing of the assumption) that complex carbohydrates or starches such as rice and potatoes were slowly digested and absorbed, causing only a small rise in blood sugar, whereas simple carbohydrates like table sugar were readily digested and rapidly absorbed, producing large and rapid increases in blood sugar and insulin levels. Upon experimentation, however, investigators found the situation to be quite variable. The so called "glycemic index" was devised to express the true situation for individual foods. The index expresses the blood glucose response for any particular food as a percentage of the response after the same weight of carbohydrate is taken in the form of pure sugar . The index of glucose would thus be 100 percent and the indices of other foods less. Surprisingly, the response does not closely correspond to whether a carbohydrate is simple or complex. The response of blood glucose to some starches is nearly as great as to refined sugars, whereas other starches give a low response. Pasta is lower than cereals. Milk is low, but cheese and bread give a high response. The glycemic indices for a number of foods are shown in Table 9.3. We see that carrots are rather high on the list and sweet potatoes low. The reasons for all these seemingly haphazard differences are not entirely known. Fiber content does not seem to be a factor in cereals, but fibers such as the guar and pectin found in fresh fruits and vegetables greatly influence the rate of carbohydrate absorption and subsequent blood sugar responses. Legumes are digested less rapidly than other foods, so produce lower, flatter glucose responses.

Other things being equal, for your high low diet choices select foods with the lower glycemic index. The list given in Table 9.3 is accurate and usable. One should not be led astray by listings which show that such items as potato chips and ice cream have low glycemic indices. They do indeed, but in these cases it's because the foods are high in fat, and fat delays emptying time of the stomach. A low glycemic index at the expense of a high fat meal is a poor trade off. Fiber is also a favored substance in the high low diet. As we recall from an earlier chapter, the term "fiber" refers to the indigestible portions of plants, the chemical substances usually present in the cell walls that give plants their structure and form. And different kinds of fiber have different effects on the body. For an average size person, fiber in take should reach 40 grams per day. Depending on your present intake, you may have to work up to 40 grams gradually to avoid temporary flatulence and bloating. But 40 grams is a minimal amount, and most vegetarians consume a lot more. Sixty grams may be a quite reasonable amount. A word of caution: consuming very large amounts of fiber between meals in the form of processed material like guar gum can cause sigmoid volvulus, a twisting and impaction of the colon. The amount of fiber should be split more or less equally between cereal fibers, such as bran, and the gums and pectins, found especially in apples, pears, peaches, oranges, rolled oats, and dried beans. Bran fiber does not influence cholesterol, but adds build and softness to the stool. Miller's bran can be added to your breakfast cereal; two tablespoonfuls weigh about 3 grams. The pectins and gums can reduce cholesterol levels. Fruits, vegetables, and beans will supply these fiber types. Oat and rice bran will also reduce cholesterol.

A high fiber diet will also help you control your weight. Fiber is filling but adds virtually no calories. Three apples contain about 24 grams of fiber, but their carbohydrates content equals that of only one fiber less candy bar. Many cereal manufacturers and some bread makers include fiber information in their nutrition rundown on the back of the package. Look for the words "dietary fiber," not just "crude fiber. " You want the former. "Crude fiber" dates back to 1887, and the test on which it is based doesn't pick up a number of materials now recognized as being "fiber." In Table 5.4 I listed the fiber contents of representative portions of a number of common foods. Others are given in the appendix to this volume.