By John A. McDougall, M.D.

Dr. John & Mary McDougall

Dr. John & Mary McDougall

Two recent publications clearly demonstrate the effects of diet on bone health (osteoporosis) and kidney stone formation. On the destructive side, research from the University of Chicago looked at the effects of the high protein Atkins diet on calcium balance.1 Data was collected for 2 weeks of the Atkins induction diet and 4 weeks on the maintenance diet. The induction diet contained 164 grams of protein a day and the maintenance 170 grams/day. The Atkins diet produced an acid load, because animal proteins are high in sulfur-containing amino acids, which break down into very potent sulfuric acid.2 Dietary acids must be buffered to prevent an acidic build-up in the body. The bones provide the alkaline materials to neutralize the acids. The end result was a large increase in calcium loss into the urine caused by the breakdown of bone materials. (The calcium balances decreased by 130 mg/day and 90 mg/day, respectively on the two phases of the diet). Markers of bone resorption increased, suggesting loss of bone during this short 6 week trial. Eventually, chronic calcium loss results in osteoporosis. The large amount of calcium in the urine, along with other changes produced by a diet high in animal proteins, is a setup for calcium-based kidney stones. Over 95% of kidney stones in Western societies are made primarily of calcium.

On the constructive side, a study from the University of Applied Sciences in Germany examined vegans (on an all vegetable-foods diet with no animal protein) and found them to be in positive calcium balance—more calcium entered the body than left.3 The balance was a positive 119 mg/day. There were no changes in markers of bone resorption, suggesting the bones were not breaking down. The vegans consumed an average of 843 mg of calcium a day from their foods and calcium-rich mineral water.

These effects of animal protein on bone health are not limited to only 2 weeks as has been claimed by some poorly informed people (such as Robert Atkins claiming that the calcium losing effects of his diet are limited to 2 weeks, on the January 6, 2002 Larry King Live CNN-TV Show), but continues as long as the person’s diet is high in protein.1,4 Therefore, to save your skeleton and prevent kidney stones, you need to follow a (vegan) diet based on starches, vegetables, and fruits; and limit rich foods to special events, such as turkey for Thanksgiving and fish for a special night out. Bone loss is reversible,5 and there is every reason to believe that with a healthy starch-based diet and exercise the skeleton will become stronger and the possibility of fractures will be lowered.


  1. Reddy ST. Effect of low-carbohydrate high-protein diets on acid-base balance, stone-forming propensity, and calcium metabolism. Am J Kidney Dis. 2002 Aug; 40(2):265-74.
  2. Barzel US. Excess dietary protein can adversely affect bone. J Nutr. 1998 Jun; 128(6):1051-3. Review.
  3. Kohlenberg-Mueller K. Calcium balance in young adults on a vegan and lactovegetarian diet. J Bone Miner Metab. 2003;21(1):28-33.
  4. Hegsted M. Long-term effects of level of protein intake on calcium metabolism in young adult women. J Nutr. 1981 Feb; 111(2):244-51.
  5. Doty SB. Pathophysiology of immobilization osteoporosis. Curr Opin Orthop. 1995 Oct; 6(5):45-9.

©2003, John McDougall. All Rights Reserved.

John A. McDougall, M.D.
Physician and nutrition expert who teaches better health through vegetarian cuisine. John A. McDougall, MD. has been studying, writing and “speaking out” about the effects of nutrition on disease for over 30 years.

Dr. McDougall believes that people should look, feel great and enjoy optimal health for a lifetime. Unfortunately, many people compromise their health unknowingly through poor dietary habits.

Dr. McDougall is the founder and medical director of the nationally renowned McDougall Program, a ten-day, residential program located at a luxury resort in Santa Rosa, CA—a place where medical miracles occur through proper diet and lifestyle changes. Dr. McDougall has cared for thousands of patients over almost 3 decades of medical practice and has run a highly successful live-in program for more than 17 years. Dr. McDougall has developed a nourishing , low-fat, starch-based diet that not only promotes a broad range of dramatic and lasting health benefits such as weight (fat) loss, but most importantly can also reverse serious illness, such as heart disease, without drugs.

As with many leaders of public opinion, he often finds it necessary to challenge the accepted wisdom of the time, and was one of the first traditional physicians of the medical “establishment” to assert that adoption of a vegetarian diet can reverse unfavorable medical conditions such as heart disease. Medical research is now confirming this assertion. And slowly but surely, medical practitioners are accepting it.

Dr. McDougall is the author of several national bestsellers including: The McDougall Plan: 12 Days to Dynamic Health, McDougall’s Medicine: A Challenging Second Opinion, The McDougall Program for Maximum Weight Loss, The New McDougall Cookbook, The McDougall Program for Women, and his latest ground breaking book, The McDougall Program for a Healthy Heart.

A graduate of Michigan State University’s College of Human Medicine, he performed his internship at Queen’s Medical Center in Honolulu, Hawaii, and his medical residency at the University of Hawaii. He is certified as an internist by the Board of Internal Medicine and the National Board of Medical Examiners.

To make it easier for people to eat well on the go, Dr. McDougall co-founded Dr. McDougall’s Right Food’s Inc., a producer of high quality vegetarian cuisine. The convenience meals are consistent with his health-supporting guidelines of 10% or less calories from fat, strictly vegetarian so there’s no cholesterol, and no added oils. Dr. McDougall is the Chairman of the Company.