What Harm Does Sugar Cause?
What Harm Does Sugar Cause?
As for sugar’s reputed adverse health effects, the following can be said on the basis of available evidence:
Obesity. Sugar supplies 4 calories per gram (113 per ounce) – the same as protein and less than half that of fat, which provides 9 calories per gram. Excess calorie intake, not sugar, causes obesity. But since calories can be highly concentrated in sugar-sweetened foods, you may eat many more calories than you need of such foods before you feel full or even realize how much you have consumed. Compare the satiety value of, say, three bananas with that of a two-ounce candy bar; both have about the same carbohydrate content. Fructose, the primary sugar in fruits, is 50 percent sweeter than sucrose, and so fewer fructose calories are needed to obtain the same degree of sweetness. However, the use of fructose in nutritionally deficient sweet foods does little to improve their health value.
Tooth decay. Sugar definitely promotes the development of dental caries. Bacteria in the mouth digest the sugar on tooth surfaces and produce acid, which etches the protective tooth enamel and fosters periodontal disease. It is the frequency of sugar consumption and the amount of time sugar remains on the teeth, rather than the total quantity of sugar eaten, that makes the difference.
Thus, chewy candies, sucking candies, and sweetened cereals (whether sweetened by sugar or honey) are far more harmful to the teeth than a sweet drink or ice cream. Sweet, chewy granolas, the latest rage in breakfast cereals, are bad actors as far as teeth are concerned. (They also are not sufficiently more nourishing than regular cereals to justify their high calorie and sugar content.) To reduce the risk of decay, dentists recommend that you rinse your mouth or brush your teeth after consuming anything sweet and that you avoid eating sweets between meals.
Diabetes. In diabetes, the pancreas fails to produce adequate amounts of insulin to clear the blood of excess glucose. Thus, diabetics are told to curb their intake of sweets lest their blood sugar rise dangerously high. Eating a lot of starch, however, is not harmful to diabetics. The most important dietary factor in diabetes is controlling body weight.
There is some evidence that a high-sugar diet may promote the development of diabetes in people who are genetically predisposed to the disease. In laboratory experiments, rats prone to diabetes develop the disease on a high-sugar diet, but not on a sugar-free diet. When Yemenites, who ordinarily eat little sugar and have no diabetes, emigrate to Israel and adopt a sugar-rich diet, they frequently develop obesity and diabetes. However, other populations with high-sugar diets have lowrates of diabetes, perhaps because they are not overweight.
Heart Disease. The theory that diets high in sugar are an important cause of atherosclerosis and heart disease does not have wide support among experts in the field, who say that fats and cholesterol are the more likely culprits. Although most of the countries that consume a lot of sugar have a high incidence of heart disease, these are the same countries where consumption of animal fats and cholesterol is very high. There is a much stronger correlation worldwide between fat consumption and heart disease.
Well-controlled studies have shown that people who developed heart disease did not consume excessive sugar compared with those free of heart disease. A high-sugar diet does not cause heart disease in experimental animals, whereas a high-fat diet does.
Some people are said to be carbohydrate-sensitive – they have a tendency to develop high blood levels of fatty substances called triglycerides, which may promote atherosclerosis. They are often advised to reduce their intake of sugar, but reducing dietary fat and losing weight are most important to lowering their triglyceride level. Diets free of sucrose can lower abnormally high blood fat levels, but they have been found to have no effect on fat levels that are acceptable to begin with.