High-protein diets have no proven effectiveness in long-term weight reduction and pose potential health threats for those who adhere to them for more than a short time, according to a report from the American Heart Association's Nutrition Committee. The report specifically targets popular "quick weight loss" regimes such as the Atkins, Zone, Protein Power, Sugar Busters and Stillman diets, and offers guidelines to health care professionals for evaluating these diets. "High-protein items may also be high in fat. Some of the diets increase fat intake and reduce nutritionally rich foods such as fruits and vegetables, which is not a good approach to meeting a person's long-term dietary needs," said Robert H. Eckel, co-author of the advisory and professor of medicine at the University of Colorado Health Science Center in Denver. "Many of these diets fail to provide essential vitamins, minerals, fibre and other nutritional elements, in addition to their high fat content," he continued. One of the most compelling arguments against following a high-protein diet, Eckel says, is that these diets have not been documented to deliver on their promise of sustained, long-term weight loss. The safety, credibility and effectiveness of the revised American Heart Association nutritional guidelines, on the other hand, are backed by scientific documentation, he adds. "It's important for the public to understand that no scientific evidence supports the claim that high-protein diets enable people to maintain their initial weight loss," he commented. Studies, he continued, have consistently shown that successful, maintenance of weight loss occurs most often when people follow a nutritionally sound diet and increase physical activity to burn more calories than they consume. Foods emphasised in some of these high-protein and similar diets are from animal sources that are rich in both protein and saturated fat such as meat and eggs. Meanwhile, some of the diets drastically limit consumption of high-carbohydrate foods such as cereals, grains, fruits, vegetables and low-fat milk products, Eckel stressed. Eating large amounts of high-fat animal foods over a sustained period has been shown to increase the risk of coronary heart disease, diabetes, stroke and several types of cancer. The statement notes that a diet rich in animal protein, saturated fat and cholesterol raises LDL cholesterol levels - an effect that is compounded when high-carbohydrate, high-fibre plant foods that help lower cholesterol are limited or eliminated.