Story last updated at 8:08 a.m. Sunday, January 5, 2003
Long-term health problems associated with high-protein diets
By MARTHA MURPHY
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High-protein. Low-carbohydrate. You've probably seen the results. A close friend, a relative or maybe a favorite celebrity losing a noticeable amount of weight on one of the highly publicized high-protein, low-carbohydrate diets.
Whether it's the Atkins Diet, the Sugar Buster Diet or Protein Power, these diets all promise weight loss if you restrict consumption of foods high in carbohydrates (fruit, cereals, pastas and breads) and eat lots of protein-rich foods such as meat, milk, eggs and nuts.
Indeed, weight loss usually occurs, sometimes rapidly, however not strictly as a result of reducing carbohydrate intake and eating high amounts of protein. Rather, these diets are low-calorie. During the first week the pounds you drop are a result of water loss, not body fat loss. You lose body fat after that only if you continue eating fewer calories than you burn. This is not solely a characteristic of high-protein diets, but is true of any low-calorie diet. It may be easier for some people to adhere to a low-calorie regimen while on a high-protein diet because the allowed foods make them feel full.
The authors of high-protein, low-carbohydrate diets also cite the conversion of the body's metabolism to ketosis as an advantage in accelerating weight loss. Ketosis is a normal metabolic state only during starvation conditions, but also can be achieved in people eating minimal amounts of carbohydrates.
A tell-tale sign of ketosis is acetone breath, sometimes described as an odor that is a cross between nail polish and over-ripe pineapple. Fatigue and constipation, sometimes accompanied with nausea and vomiting, are common side effects. If one continues to be in a ketotic state, the stresses placed on the body can lead to kidney damage, gout, osteoporosis, heart disease and cancer.
Kidney Disease: When people eat too much protein, additional strain is placed on the kidneys. Large amounts of protein cause nitrogen to be released into the blood, which the kidneys must filter out and excrete in the urine.
Gout: During ketosis, a chemical called uric acid begins to build up in the blood. This promotes the development of gout, a painful condition of the toes and joints.
Osteoporosis: When excess protein, especially from animal sources, is eaten for an extended time, the body flushes more calcium out through urine, which may contribute to osteoporosis.
Heart Disease: High-protein diets tend to promote eating more meat, eggs and dairy products which, in addition to being protein-rich foods, are generally high in fat, saturated fat and cholesterol. Numerous studies have shown that diets high in fat and saturated fat can increase a person's risk of heart disease.
Cancer: Eating a diet rich in whole grains, fruits and vegetables has repeatedly been shown in scientific studies to be important in reducing the incidence of some cancers. Such a diet contains vitamins, minerals and fiber, which have been linked to the prevention of cancer, strokes and heart disease. High protein diets severely limit the consumption of these high-carbohydrate foods.
The bottom line is that carbohydrates alone do not make people fat. Eating too many calories and engaging in too little activity causes people to gain weight. So, although high-protein diets may result in short-term weight loss, the risks they pose for long-term health problems outweigh the benefits. The best weight loss program is still a reduced-calorie diet containing good amounts of protein balanced with fruits, vegetables and whole-grain foods and a regular activity program.
For other nutrition and food safety questions, contact me at 620-232-1930 or e-mail me at mmurphy~oznet.ksu.edu or check out the K-State Research and Extension website:
http://www.oznet.ksu.edu/humannutrition/
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