Nutritional disorders

Abstract

The normal diet contains, 2,500–3,000 Calories daily—the dietetic Calorie is in fact a kilocalorie, 1,000 times a chemical ‘calorie’. Of the daily calorie intake 40–50 per cent is derived from carbohydrate, about 12 per cent from protein, and 42 per cent from fat in Western countries. It will be remembered that 1 G of carbohydrate or protein produces 4 calories, and 1 G of fat 9 calories. Thus an average diet contains 350–400 G carbohydrate, 70–90 G protein and 110–140 G fat. A mixed diet supplies adequate minerals (salt, potassium, calcium, magnesium, iron) trace elements such as iodine, and vitamins. The relative excess of carbohydrate, especially refined carbohydrate such as sugar, has been blamed for many of the ills of civilized society—especially diabetes and arteriosclerosis. Dental caries is related to a high sugar and sweet intake. Too much animal fat in the diet is associated with a raised cholesterol level and possibly a raised incidence of arteriosclerotic coronary disease. The substitution of certain vegetable oils for fats lowers the blood cholesterol, but it has yet to be shown that this prevents coronary disease. Much research is being carried out into the relationship between dietary habits in the West and the high incidence of arterial disease in the population.