1. Introduction and Methods
Extract from "Updated Analysis of Health Problems Associated with High-Protein, High-Fat, Carbohydrate-Restricted Diets Reported via an Online Registry" by the Physicians Committee for Responsible Medicine (PCRM) (Dec, 2003)
Note: Numbers in brackets refer to research references. See Low Carb Eating References
While a few recent studies have noted that high-protein, carbohydrate-restricted diets facilitate modest short-term weight loss,(1-3) no studies to date have investigated the long-term health consequences of consuming such diets for weight-loss purposes.
Diets high in fat, especially saturated fat, are associated with increased risk of cancer,(4-6) diabetes, (7) and heart disease.(7) Diets high in animal protein have been shown to increase the risk of kidney problems, (8,9) osteoporosis, (10,11) and some types of cancer.(12,13) Because fiber is found only in plant foods, and high-protein, high-fat, carbohydrate-restricted diets tend to be low in plant foods, these diets are also typically low in fiber. Low fiber intake is associated with increased risk of colon cancer and other malignancies, (4) heart disease, (7) diabetes, (14,15) and constipation. (16)
Some high-protein, very-low-carbohydrate, weight-loss diets are designed to induce ketosis, a state that also occurs in uncontrolled diabetes mellitus and starvation. When carbohydrate intake or utilization is insufficient to provide glucose to the cells that rely on it as an energy source, ketone bodies are formed from fatty acids. An increase in circulating ketones can disturb the body’s acid-base balance, causing metabolic acidosis. Even mild acidosis can have potentially deleterious consequences over the long run, including hypophosphatemia (low blood phosphate levels), loss of calcium from bone, increased risk of osteoporosis, and an increased propensity to form kidney stones. (17)
For these reasons, high-protein, high-fat, low-fiber, carbohydrate-restricted diets, such as the Atkins Diet, especially when used for prolonged periods, are expected to increase the risk of multiple chronic diseases and other health problems, despite the weight loss that may accompany their use. Herein, we summarize the reports of individuals who have experienced health problems while on a high-protein, high-fat, carbohydrate-restricted diet who have offered their information through an online registry (www.atkinsdietalert.org/registry.html). The seriousness of the reported health problems highlights the importance of tracking the impact of the use of these potentially risky diets and the need for research into the long-term health consequences of using these diets for weight loss and maintenance.
Methods
In the fall of 2002, the Physicians Committee for Responsible Medicine began a pilot program testing the feasibility of an online registry for identifying people who may have suffered health complications related to high-protein, low-carbohydrate diets. A modest Internet advertising campaign was used to notify consumers about the availability of this registry. In November of 2003, PCRM held a news conference highlighting the health problems suffered by some individuals using these diets and drawing attention to the registry.
To report problems with high-protein, high-fat, carbohydrate-restricted diets, individuals voluntarily visited www.atkinsdietalert.org and filled out a form available on the site. The registry specifically inquires about the following problems: heart attack, other heart problems, high cholesterol, diabetes, gout, gallbladder, colorectal cancer, other cancers, osteoporosis, reduced kidney function, kidney stones, constipation, difficulty concentrating, bad breath, and loss of energy. In addition, many registrants related other problems they had experienced while on Atkins-like diets in an “other problems” box offered on the registry. Many registrants reported more than one health concern. Through this online form, most registrants also provided contact information, age, sex, previous health concerns, length of time on the diet, reasons for choosing the diet, and other information.
To help clarify the possible biological mechanisms by which a high-protein, high-fat, carbohydrate-restricted diet might lead to these problems, PCRM dietitians conducted nutrient analysis of the sample menus for the three stages of the Atkins Diet as described in Dr. Atkins’ New Diet Revolution (Avon; 2001; pp. 257–259), using Nutritionist V, Version 2.0, for Windows 98 (First DataBank Inc., Hearst Corporation, San Bruno, Calif.)
INDEX to PCRM Low Carb Health Problems Report
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The PCRM Report:
- Introduction and Methods
- Findings
- Nutrient Analysis
- Discussion
of Health Concerns
- Constipation
- Lack of Energy
- Bad Breath
- Lack of Concentration
- Kidney Problems (and Gout)
- Heart Disease
- Gall Bladder Problems
- Diabetes
- Cancer
- Limitations of Weight Loss - References
- Appendix: Diet Menus Used for Nutrition Analysis
