The rise in popularity of low-carbohydrate and high-protein diets has left carbohydrates with the reputation of diet busters. While such diets designed to limit your carb intake might help you lose weight, the loss might come at a cost to your health. Before you begin any new diet program, speak with your health care provider about a plan that's right for you.
Excess Protein Intake
The 2010 USDA Dietary Guidelines for Americans suggest adults get 10 to 35 percent of daily calories from protein. For an individual on a 2000-calorie-per-day diet, this equates to 200 to 700 protein calories, or 50 to 175 g of protein each day. On average, Americans already eat more than their recommended daily allowance of protein. The excess protein intake required for some low-carb diets means you're eating protein your body can't use, and this protein gets stored as fat. The process of metabolizing protein consumes water, puts stress on your kidneys and can lead to a loss of urinary calcium. A diet high in protein, especially if followed for more than a year, can cause kidney problems and bone loss.
Ketosis
When you restrict your carbohydrate intake, your body releases ketones into your bloodstream and begins turning to fat for energy in place of carbs. As this occurs, your body doesn't break down fats completely, and you might suffer from ketosis, which can cause you to feel weak, sluggish, irritable, nauseated or dizzy, and might lead to dehydration.
Saturated Fat and Cholesterol
While not all low-carb, high-protein diets are the same, many allow you to eat foods high in saturated fat and cholesterol, such as red meats, cheese and full-fat dairy. Consuming more than 10 percent of your daily calories in saturated fats or eating more than 300 mg of cholesterol daily increases your risk of heart disease and certain cancers.
Fiber Deficiency
Restricting simple, processed carbs such as alcohol and sugar can help you lose weight and prevent several health conditions, but your body needs carbs to survive. The 2010 USDA Guidelines said 45 to 65 percent of daily calories should come from carbs. A diet that limits your intake of whole grains, fruits and vegetables could lead to a fiber deficiency, putting you at risk of digestive problems like constipation.
Question of Weight Loss
Much of the early weight loss seen in low-carb diets is a result of water loss from the diuretic effect of the diet, making it easier to gain back quickly after stopping the diet. According to Mayo Clinic preventive medicine specialist Dr. Donald Hensrud, overall weight loss is about the same after one to two years when comparing low-fat diets with low-carb ones, and dieters following both types of programs exhibit a wide range of results.
References
- USDA: Dietary Guidelines for Americans 2010
- American Council on Exercise; "I'm Looking to Gain Weight and Add Muscle To My Frame -- Should I Be Consuming Extra Protein?; Jessica Matthews"; September 2009
- University of Maryland Medical Center; Low-Carb Diets; "The Right Way to Go?"; April 2007
- MayoClinic.com: Low-Carb Diet
- MayoClinic.com; "Low-Fat Vs. Low-Carb"; Dr. Donald Hensrud; September 2010
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