Adverse effects of high protein diets

With high protein diets being a major trend right now, I thought it necessary to shed some light on the health implications associated with such diets. Atkin’s and Paleo diet advocate a high protein diet is healthful and supports weight loss. Even major food companies have tapped into this new trend – Cheerio’s recently came out with a new line advertising their product as a good source of protein, Greek yogurt boast’s double the protein than the original yogurt, and protein bars and shakes typically offer 20 grams of Protein per serving! Clearly high protein diets are increasing in popularity, but what are the long-term health consequences? Could it lead to disorder’s of health?


First, it’s important to say that protein is an essential nutrient needed for muscle, tissue’s, hormone’s, etc. Animal sources of protein are meat, poultry, fish, eggs, and dairy, while plant foods high in protein are legumes, nuts, and grains. The current recommendation for protein is 0.8 g protein/kilogram (kg) body weight per day for healthy adults (Click the link).

What are the health consequences?

Diet’s high in protein create a large amount of acid in the body. We could die from too much acid so our bodies must balance the acid with a base – calcium! The skeleton supplies a buffer (base) by removing calcium from our bones. Also, acid loading causes high levels of calcium in the urine. A double loss of calcium! In a study by Reddy et al. (2002),  Participants on a low-carb high-protein diet for 6 weeks had increased calcium levels in urine and decreased calcium balance. In another study by Sellmeyer et al. (2001),  showed that a high ratio of animal protein to vegetable protein increases the rate of bone loss and the risk of fracture in postmenopausal women. Animal foods provide acid precursors, while protein found in vegetable foods has basic precursors not found in animal foods. Perhaps, a more plant-based diet could have beneficial health effects? Gotta say that I am not surprised!

Also high protein diets may increase your risk of kidney stones. Excessive intake of protein are risk factors for kidney stones. As we know, protein intake creates an acidic environment for your body. Any extra protein not used by the body for function is turned into uric acid AKA urine. In very acidic environment, uric acid precipitates into stones. Also, because calcium is taken from your bones and sent to the kidney’s for excretion, high levels of calcium in the kidney could also precipitate and form kidney stones. It’s also important to consider that kidney stone formation may be caused by genetics, medications, or metabolic abnormalities.

Bottom Line: Balance your food groups. It’s important to eat protein but no need to go overboard, eat your fruits and vegetables as they help balance your bodies acidity and basicity.

  1. Delimaris I. Adverse Effects Associated with Protein Intake above the Recommended Dietary Allowance for Adults. ISRN Nutr. 2013;2013:126929.
  2. S. T. Reddy, C.-Y. Wang, K. Sakhaee, L. Brinkley, and C. Y. C. Pak, “Effect of low-carbohydrate high-protein diets on acid-base balance, stone-forming propensity, and calcium metabolism,”American Journal of Kidney Diseases, vol. 40, no. 2, pp. 265–274, 2002
  3. D. E. Sellmeyer, K. L. Stone, A. Sebastian, and S. R. Cummings, “A high ratio of dietary animal to vegetable protein increases the rate of bone loss and the risk of fracture in postmenopausal women,”American Journal of Clinical Nutrition, vol. 73, no. 1, pp. 118–122, 2001.

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