Today’s most popular diets fall into two general categories: low carbohydrate-higher protein and more balanced, nutrient-low calorie. My previous column explored three balanced, nutrient-low calorie weight-loss plans. This week, we’ll take a look at three popular low carbohydrate weight-loss plans.
South Beach Diet: Created by Dr. Arthur Agatston, the South Beach Diet is a three-phase weight-loss plan based on the idea that eating "good" carbohydrates (whole grains, fruits, vegetables) instead of "bad" carbohydrates (pasta, refined grains) will stop insulin resistance, curb cravings and cause weight loss. The diet plan also recommends "good" fats (monounsaturated fats) over "bad" fats (saturated fats, trans fats) to help protect the heart and prevent hunger.
Phase one of the diet, which lasts two weeks, is a period of strict dieting where nearly all carbohydrates are avoided. Phase two allows "good" carbohydrates, defined using the glycemic index, to be slowly re-introduced. This phase lasts until your desired weight is reached. During phase three, you return to a normal, healthy, balanced diet to maintain your desired weight.
Overall, phases two and three of the South Beach Diet emphasize a heart-healthy eating plan that includes whole grains, lean protein and dairy, unsaturated fats, fruits and vegetables, consistent meal and snack times, and drinking eight glasses of water a day.
Phase one is very low-calorie and potentially may cause overly accelerated weight loss. Also, the diet does restrict certain fruits and vegetables unnecessarily, and vegetarians following the South Beach Diet may have difficulty consuming enough protein and calories.
The Atkins Diet: Devised by Dr. Robert Atkins, the Atkins Diet is a high protein, low carbohydrate diet centered around the belief that carbohydrates cause high insulin levels, and therefore, a low carbohydrate diet is the key to both weight loss and good health. It also has three phases. During phase one, the Induction Phase, carbohydrates are strictly limited in order to force the body into a state of ketosis. When in ketosis, the body believes that it is starving because carbohydrates, the body’s preferred energy source, are not available for it to burn for energy. Instead, the body is forced to burn fat. Phase two, the On-Going Weight-Loss Phase, allows carbohydrates to be slowly re-introduced until the body comes out of ketosis. Phase three, the Maintenance Phase, begins when you are near your target weight. Carbohydrates are still limited during this phase, which is supposed to become your life-long eating plan.
The Atkins Diet emphasizes seafood, poultry, red meat, eggs, cheese, salad vegetables, oils, butter and limited amounts of fruits, legumes and whole grains. Restrictions on fruits, vegetables, whole grains, legumes and low-fat dairy may lead to a diet low in fiber and certain vitamins and minerals. Constipation may occur due to the lack of fiber.
The Zone Diet: Developed by Barry Sears, the Zone Diet is based on the premise that eating the right balance of protein, carbohydrates and fat at each meal (40 percent, 30 percent, 30 percent, respectively) will keep you trim and healthy by optimizing the body’s metabolic function and regulating blood-sugar levels. The program promotes eating regular meals that are low in calories and saturated fat. Recommended foods include lean proteins, seafood, fruits, most vegetables, low-fat dairy and nuts.
Following the Zone Diet requires calorie counting and calculating the 40/30/30 balance at every meal, which can be complicated. Also the diet is low in calories (typically 800 to 1,200 calories per day), which may make it difficult to follow for the long term.
Low-carb diets are often effective in producing weight loss, in part because they end up being low-calorie. The key, though, to successful weight loss lies in the ability to maintain the losses seen through exercise and a balanced diet that promotes good health. Based on the findings of the National Weight Control Registry and others, this generally means getting regular exercise and maintaining a life-long eating plan that is lower in fat and higher in complex carbohydrates and fiber than found in the typical low-carb, high-fat diet plan.
by Pat Kendall, Ph.D., R.D., Food Science and Human Nutrition Specialist, Colorado State University, Cooperative Extension