High protein diet – Hazards

Relatively little evidence has been gathered regarding the effect of protein on the development of chronic diseases. While there was initial suspicion that high-protein diets increased the risk for renal failure, studies have shown that kidney problems occur only in people with pre-existing kidney disease. Similarly, the long-held concern that it could worsen hepatic encephalopathy (brain disease due to malfunction of the liver) appears to be unfounded.

The increased load on the kidney is a result of an increase in reabsorption of NaCl. This causes a decrease in the sensitivity of tubuloglomerular feedback, which, in turn, results in an increased glomerular filtration rate. This increases pressure in glomerular capillaries. When added to any additional renal disease, this may cause permanent glomerular damage.

High protein diets claim to shave pounds by making your body burn fat. That process is jump-started by eliminating all or most carbohydrates, the foods your body uses to make sugar to feed cells. In most of these diets, protein makes up about 25 to 30 percent of the day’s meals — more than twice the amount of protein that non-dieters eat. The health hazards lie in what kind of protein you do eat, doctors say.

If you were on Dr. Atkins’ diet plan, for example, you could eat foods high in saturated fats, including eggs, bacon, butter, and poultry. If you were on the Sugar Busters diet, so-called “acceptable foods” would include such high -fat fare as butter and cheese, but you’d have to cut out anything made with white flour, sugar, and starchy vegetables such as corn. The Stillman diet also allows you to eat all you want of lean meats, chicken, turkey, eggs, lean fish, and cottage and low-fat cheese until your hunger is satisfied.

Other low-carb eating plans, however, such as The Zone diet, advise people to avoid saturated fats and suggest eating low-fat proteins such as white-meat chicken, fish, and vegetables. The South Beach Diet emphasizes lean meats, such as chicken, turkey, fish, and shellfish.

Dieters lose weight for several reasons, not the least of which is that diets typically restrict calories to fewer than 2,000 a day. (That’s roughly 700 fewer calories than in the typical American diet.) With fewer calories to use, your body is forced to look for other sources of fuel to burn. If you’re not eating carbohydrates, your body breaks down fat cells. This breakdown of fat produces a buildup of toxic chemical compounds (ketones) in your blood. When there are too many ketones in your blood, your body eliminates them in your urine. Eliminate too many ketones, and you also eliminate too much water; without replacing it, you can suffer severe dehydration and the risk of abnormal heart rhythms. Since many of the diets eliminate fruit, vegetables, and whole-grain foods, and the fiber that goes along with them, dieters can also be prone to constipation.

Although you might lose weight initially, numerous studies have shown low-carb, high -fat plans to be ineffective over time, and they may in fact be harmful to your health. Most doctors and nutritionists agree that such plans keep you from getting essential nutrients, vitamins, and fiber found in plants, all of which help prevent disease and protect your health. Moreover, losing weight on this type of diet can lead to more serious health problems than being overweight, according to individual physicians and several leading US health organizations. A few of their findings:

  • In 2002, the American Kidney Fund cautioned that low-carb diets have the potential to cause scarring in the kidneys, which have to process more wastes from excess protein.
  • The increase in uric acid from low-carb diets can lead to gout, a disease that causes painful inflammation in the joints, severe dehydration, and weak bones, according to physicians Michael F. Roizen and John La Puma, authors of The Real Age Diet, a book about eating to stay young. Gout has long been linked to a diet of foods such as meat, poultry, seafood, eggs, seeds, and nuts, which can increase uric acid.
  • In a 2001 report on low-carb diets, the American Heart Association warned that filling up on protein-rich foods that are high in fat can increase the risk of heart disease, high cholesterol, diabetes, stroke, and certain kinds of cancer.

“Low-carb diets in their own right may [also] damage the kidneys, particularly if kidney disease is already present,” says Robert Eckel, MD, a professor of medicine and physiology at the University of Colorado Health Sciences Center and one of the authors of an American Heart Association report on low-carb diets. When the AHA reviewed several popular low-carb weight-loss plans, it was especially harsh on those that had dieters eat high amounts of animal protein, saturated fats, and cholesterol. Forsake more healthful choices such as fruit and vegetables in favor of foods with high er levels of saturated fats, and your diet may lead to high blood pressure and heart disease, the AHA said.

The AHA’s 2006 revised diet and lifestyle guidelines recommend limiting saturated fats to 7 percent of daily calories and the AHA notes that a high protein diet makes that very difficult to accomplish. The Atkins diet, for example, allows 26 percent of your calories to come from heart-clogging saturated fat, and the Stillman diet and The Zone allow 13 and 9 percent saturated fat, respectively.

Although the AHA said all the diets would promote weight loss, the researchers pointed out that none of them was very practical, because they all limited food choices and were difficult to maintain over time.

The Atkins diet also received harsh criticism from researchers with the Nutrition Action Health Letter. When the group completed a nutritional analysis of weight-loss books in 2001, it judged the Atkins diet “unsafe” or “unacceptable” due to its high allowance of saturated fats. Nutrition Action gave Pritikin and The Zone low-carb diets a rating of “acceptable.”