High protein diets: How safe are they?

by Rebecca N. Schiller, MSc

This article was originally published in June 2002

Fruits and vegetables contain antioxidants and fiber

I have this friend who needed to lose a quick 25 pounds in order to qualify for a life insurance policy. He shopped around a bit and decided to start a high-protein diet. “It’s great!” he told me. “I can eat all the meat, chicken and fish I want, and there’s no counting calories or fat grams. I’ve lost 15 pounds already!” In the end he didn’t reach his goal but his situation raised a few questions for me. High-protein diets seem to work; my friend did lose 15 pounds in a relatively short period of time. The big question is, are they safe?

High-protein, low-carbohydrate diets are gaining popularity within the “weight loss” world. Surprisingly, little research has been done to determine the health benefits or hazards of consuming such a diet over a long period of time. High-protein diets typically are also high in both saturated (animal) fats and cholesterol. Increased intake of these fats has been linked to a number of diseases including heart disease and prostate and colorectal cancer. Additionally, reducing your intake of whole grains, legumes, fruits and vegetables can lead to a decrease in daily antioxidant and fiber intake; a situation also linked to increased risk of disease, specifically cancer, heart disease and diabetes.

Long-term, high-protein diets are rough on the kidneys and liver because these organs have to work harder to process excess protein byproducts (urea and ammonia). Protein also contains high levels of purines, a compound that is eventually broken down into uric acid. Consuming large amounts of protein can significantly increase uric acid production and can lead to the development of gout.

Finally, when the body does not get enough carbohydrates, it begins to produce acid-like compounds called ketones. These compounds throw your body off balance by increasing blood acidity and can cause dehydration, dizziness, weakness and headaches.

Most high-protein diets are based on the premise that excessive consumption of carbohydrates raises insulin levels, which in turn increase fat storage. Studies show, that protein also stimulates the secretion of insulin. Studies have also shown that the majority of weight loss occurs within the first few weeks, suggesting that this result has more to do with fluid loss and appetite suppression than actual fat loss.

The recommended daily allowance for protein intake is 0.8 grams per kilogram of body weight (or 0.36 grams per pound). The American Heart Association recommends that 15 percent of your daily caloric intake should come from protein, 55 percent should come from carbohydrates and 30 percent should come from fat. This means that my friend (who weighs about 170 pounds now) should be consuming 60 to 75 grams of protein per day, instead of his current 120 grams.

The bottom line is that while a high-protein diet may lead to initial loss of pounds, there is no indication that it will lead to a permanent weight loss. Additionally, there have been no studies examining the health effects of a long-term, high-protein diet. Current research suggests that adding more whole grains, legumes, fruits and vegetables to your diet not only reduces your risk of disease but also may slow the aging process in general.

Rebecca N. Schiller received her MSc in Nutritional Sciences from Bastyr University. She was the recipient of a cancer research fellowship award in 1998 and 1999 from the National Cancer Institute and has contributed to research conducted at both the Fred Hutchinson Cancer Research Center and the University of Colorado Health Sciences Center. She currently works as a senior writer for a Seattle based company, BioHealth Writers.

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