Each year, some 50 million Americans go on diets for weight loss. That means about 30 billion dollars is being spent each year on diet foods, diet sodas, diet books, diet videos, diet cassettes, fitness clubs, and related diet services.
Recent studies from Harvard School of Public Health indicate that the risks of diseases, such as type 2 diabetes and coronary heart disease, are strongly related to the glycemic index of the overall diet.
The drawback to the glycemic index is that the tests are not performed using typical portion sizes. So by using the glycemic index alone the blood sugar effects of foods containing only a small percentage of the carbohydrates are likely to be overstated.