What’s the theory behind low-carbohydrate diets? The theory is that carbohydrates raise blood sugar levels, which then kicks in insulin. Insulin drives blood sugar into the cells and prevents fat breakdown in the body, which means you won’t burn excess fat and lose weight.
Proponents of low-carbohydrate diets take this one step further. They say that if carbohydrates raise blood sugar and insulin levels and cause weight gain, a decrease in carbs will result in lower blood sugar and insulin levels, leading to weight loss. And because you’re not eating the carbs, your body breaks down fat to provide needed energy. Some people do lose weight on low-carb diets, but the weight loss probably isn’t related to blood sugar and insulin levels. The weight loss is more likely the result of eating fewer total calories, whether they’re from carbohydrate, fat or protein.
(Source: Mayo Clinic, online at www.mayoclinic.com.)