Concerned that the low-carb craze is causing Americans to make unwise decisions about the foods they eat, a coalition of consumer, nutrition and public health groups formed last month to criticize the diets and their long-term prospects for weight control.
The Partnership for Essential Nutrition announced the findings of a comprehensive review of the scientific literature that will serve as the foundation for its activities and advocacy effort. The group warned that low-carb diets are unlikely to lead to sustained long term weight loss and they can increase the risk for a number of life-threatening medical conditions.
"Low-carbohydrate diets conflict with decades of solid scientific research that clearly encourages us to reduce saturated fat and boost fruit, vegetable and fiber intake," said Barbara Moore, president and CEO of Shape Up America!, which founded the coalition. "Restricting carbohydrates stresses vital organs and alters brain metabolism while offering no advantages in terms of either fat loss or long-term weight control."
At a news conference in Washington, members of the Partnership for Essential Nutrition reported that their review of research concludes that losing weight on these extreme low-carb diets can lead to such serious health problems as kidney stress, liver disorders and gout. The diets also increase the risk for coronary heart disease, diabetes, stroke and several types of cancer. Moreover, the coalition identified a number of short-term side effects from low-carbohydrate diets that, although less serious, can affect a person's quality of life. These include severe constipation, gastrointestinal problems, nausea, repeated headaches, difficulty in concentrating and the loss of energy.
Eleven organizations make up the partnership: Alliance for Aging Research, American Assn. of Diabetes Educators, American Institute for Cancer Research, American Obesity Assn., National Consumers League, National Women's Health Resource Center, Pennington Biomedical Research Center, Shape Up America!, Society for Women's Health Research, University of California at Davis and Yale-Griffin Prevention Research Center.
The coalition's review also questions the effectiveness of these extreme low-carbohydrate diets for sustained weight loss. Summarizing recent scientific studies that find the rapid weight loss associated with these diets is temporary and often results in weight "snap back," the coalition voiced apprehension about the processes by which people lose weight on these diets. Specifically, the new group questioned the safety of diets that force the body into "ketosis," a process that starves the brain of carbohydrates, forcing the metabolism of protein in the muscles followed by the metabolic breakdown of fat. Of key concern is that extreme low-carb diets produce dehydration, which can stress the kidneys and increase the potential for bone loss contributing to osteoporosis.
Currently, both the Food Safety and Inspection Service, part of the U.S. Dept. of Agriculture, and the Alcohol and Tobacco Tax and Trade Bureau have issued interim guidelines for how manufacturers can make carbohydrate claims about meat and poultry products and alcoholic beverages respectively.
The coalition's actions come in response to new survey data showing the explosive growth in the popularity of "low-carb" diets is affecting the American diet in unfortunate ways. Conducted by Opinion Research Corp., this survey of 1,017 adult Americans reveals:
* One in five (19 percent) adults who are trying to lose weight are doing so primarily by reducing the amount of carbohydrates they consume.
* Compared to others trying to lose weight, many people following low-carb diets are making poor dietary choices: 50 percent are increasing their consumption of steak, 30 percent are eating more bacon and 43 percent are consuming less fruit.
* The hype over low-carb foods is affecting the rest of the population, many of whom are now consuming less fruits, vegetables, whole grains and low-fat dairy products. Compared to the five servings a day of fiber-rich fruits and vegetables recommended by the National Cancer Institute, the survey finds 68 percent now eat two or less servings of fruit a day, 63 percent consume two or less servings of vegetables, 71 percent have less than the three recommended daily servings of low-fat dairy products and 15 percent say they have cut out dairy products altogether.
At the same time, the survey finds limited understanding of the amount of carbohydrates needed each day for good health. Although the Institute of Medicine (part of the National Academy of Sciences) issued a recommendation that children and adults get a minimum of 130 grams of carbohydrate daily, only 19 percent of those surveyed knew this fact. Instead 51 percent believe that adults need significantly fewer carbs, while 21 percent have no idea. Only 10 percent believe that adults need more.