Healthy Eating & Diet

Meat Protein Risky in Low-Carb Diets

Sept. 7, 2010 -- All low-carbohydrate diets may not be created equal when it comes to your health. A new study suggests that a low-carb diet based on vegetable protein is healthier than one based on meat protein.

Low-carb diets have gained popularity in recent years as research shows they aid in weight loss and may improve some cardiovascular risk factors.

But researchers say their findings suggest that health benefits of a low-carb diet may depend on the type of protein and fat it contains.

The study followed nearly 130,000 health professionals for at least 20 years and found that low-carb diets that emphasized animal sources of fat and protein -- such as red meat -- were associated with a higher risk of death from any cause.

In contrast, people who ate low-carb diets that emphasized vegetable sources of fat and protein, such nuts and beans, had a lower risk of death from any cause, particularly heart-related death.

The study, based on regularly administered questionnaires, found that eating a low-carb diet based on meat protein was associated with a 23% higher risk of death from any cause, 14% greater risk of heart-related death, and 28% greater risk of cancer-related death. Eating a vegetable protein-based low-carb diet, however, was associated with a 20% lower risk of death from any cause and a 23% lower risk of death from heart disease.

Low-Carb Diets Compared

Researcher Teresa T. Fung, ScD, of Simmons College in Boston and colleagues say that the macronutrient content of both diets may be similar, but the source of those nutrients may create large differences in substances known to affect health, such as fatty acids, protein, fiber, vitamins and minerals, and phytochemicals.

In an editorial that accompanies the study, experts say the jury is still out on the health effects of low-carb eating plans because survey-based dietary research is unable to control for all potential confounding factors.

"The current state of the evidence is such that no one can legitimately claim that a low-carbohydrate diet is either harmful or safe with any degree of certainty until a large-scale, randomized study with meaningful clinical end points is done," write William S. Yancy Jr., MD, MHS, Matthew L. Maciejewski, PhD, and Kevin A. Schulman, MD, of the Veterans Affairs Medical Center and Duke University.