Fats in human nutrition

Summary Dietary fats represent the most compact chemical energy available to man. They contain twice the caloric value of an equivalent weight of sugar. However dietary fats should not be thought of solely as providers of unwanted calories as fats are as vital to cell structure and biological function as protein. If an individual consumes food items of high fat content, an adequate protein and vitamin intake should be assured in order to provide the lipotropic factors necessary for normal fat metabolism. It may be more judicious to control the total caloric intake under such circumstances rather than to resort to periods of semi‐starvation or to drastically decrease the dietary fat intake which could result in an increase in hunger pangs and an actual increase in total caloric intake. If the excess calories furnished by carbohydrates are converted to fat in vivo , the problem of obesity could not be solved under conditions of increased total caloric intake. The problem could be solved by a curtailed intake of a diet which includes meat, milk, eggs, vegetables, fruits, and sufficient cereals and bread to provide for an adequate protein, vitamin, and caloric intake. Dietary fats provide the essential linoleic acid which seems to have both a structural and functional role in animal tissue. Although the optimum total intake of linoleic acid by man has not been established, it is evident that the level of intake in the American dietary pattern could be increased. However the indiscriminate substitution of soft for hard fats seems undesirable as an excess consumption of highly unsaturated fatty acids may change the functional value of the triglycerides in the depot fats and may put an undue stress on the antioxidant supply available in vivo .