Fall 2004
America is low-carb crazy. Several of the most popular low-carbohydrate fad diets have achieved mainstream attention in American society, and millions have jumped on the bandwagon. But Americans are fatter than ever.
This is no coincidence. Many people who have used these diets are regaining their weight in droves and pounds, and they are doing it because the "low-carb revolution" was not telling the whole truth.
The low-carb revolution may be coming to an end. Now it is time for the resolution.
Advocates of fad diets say that we will lose weight by eating fewer carbohydrates because carbs cause insulin to be released into the body. Insulin controls blood sugar levels and tells the body to burn carbohydrates before anything else - such as fat. These diets tell people to stop or severely restrict eating all forms of carbohydrate in the first two weeks and gradually add back the carbs.
But these diets throw out the good carbs with the bad. They do not tell us that this severe carbohydrate restriction, even for a short time, will cause the metabolic catastrophe of muscle being burned along with fat and result in the weight returning - and returning with additional fat. Scientific studies show that it is not the amount of carbohydrate that causes the insulin response, but rather the type of carbohydrate.
Carbohydrates are found in three forms - fiber, starches and simple sugars - and all come from fruits, vegetables and grains. Each of these foods is most perfect in its natural state, with the sugary or starchy inner core wrapped by some form of outer fiber shell. The fiber coverings, like the skin covering an orange slice or the bran covering a wheat grain, contain vitamins and minerals as well as fiber. The more these foods are processed and broken down, the less perfect they become.
The fiber wrapping in fruits, vegetables and whole grains slows the absorption of carbohydrates into the body, prevents the insulin response and allows fat to burn. In processed foods, the fiber has been removed to make these foods sweeter - such as high fructose corn syrup - and softer - such as white bread. Because processed foods are absorbed quickly into the body, they boost the insulin response and slow the burning of fat.
Fiber is counted in the total grams of carbohydrate listed on a nutrition information label, but it is not absorbed into the body and thus contains no calories. Simply subtract the fiber grams from the total carbs to determine the net carbs in a serving of food. For example, a half cup of raspberries has eight grams of carbs but 4.5 grams are fiber, leaving only 3.5 grams of carbs to taste sweet and be absorbed as calories - just 14 calories!
Carbohydrates are crucial for maintaining good health and essential for burning fat. Eating complex "good" carbs such as fiber, veggies and fruits in sensible portion sizes - not cutting out all carbs - reduces insulin response and allows the body to use fat for fuel instead of those carbs. Eating too few good carbs ensures that any fat lost while following a fad diet will become harder to lose as time goes on and guarantees that fat will be regained. This happens because the body requires good carbohydrates to burn fat. Without good carbs to burn fat, the body instead must use muscle.
This terrible process of burning muscle to burn fat begins when less than 150 grams of carbohydrate are consumed each day. For those who are counting, low-carb diets reduce carbohydrate intake to 20 grams each day. Future attempts at weight loss are more difficult and less successful, because less muscle is available to break down and burn fat.
Exercising muscle burns fat most efficiently, and having less of it means a low-carb dieter will burn less and less fat as time goes on. When the dieter cannot lose any more muscle, the weight loss plateaus and eventually returns.
Proponents of low-carb diets say there is no better way to lose weight, and this is true - if you don't mind losing the major portion of that weight as muscle. Those using these low-carb diets will lose more weight, but they will lose less fat than if they simply maintain a healthy lifestyle. For safe and permanent weight loss of fat only, a low-carb diet is a poor choice.
The only healthy and permanent form of weight loss requires healthy food choices in proper portions with regular, vigorous exercise. Anyone trying to say differently is selling snake oil - and that's the truth.
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Lt. Cmdr. Thomas Robinson, MC, is senior medical officer at Branch Medical Clinic in Panama City, Fla.