The low-carb fad has had its peak, and although it is declining in popularity, the myth persists that eating lots of meat and little or no ‘carbs’ is a great way to lose weight.
Plenty of studies have established that low-carb diets are moderately effective for weight loss over periods of 6 months to 2 years[1-3], though much of the weight lost initially is typically regained. This may be a better option than the processed food-soda diet many other Americans consume, so of course they are moderately effective – the number of calories consumed decreases as refined carbohydrates are eliminated from the diet. Low-carbohydrate diets cause people to lose some weight but at what cost? The short durations of these studies meant that they could not determine whether the diets are sustainable for long-term health. The current state of the medical literature would suggest that they are not – there is abundant data associating high meat consumption with adverse outcomes: weight gain, cardiovascular disease, cancer, diabetes, and all-cause mortality, just to name a few.[4-10] I have been warning for years that the long-term outcome of meat-based diets would not be favorable.
A long-term observational study of low-carbohydrate diets has finally been published this Tuesday in the Annals of Internal Medicine, and the results are intriguing. This study by researchers from the Harvard School of Public Health is the nail in the coffin of the low-carb, high-protein myth. The article details data from a prospective study in which 130,000 total participants provided information about their eating habits and were followed for a minimum of twenty years – this is true long-term data. At baseline, none of the participants had heart disease, cancer, or diabetes. The researchers classified the participants’ diets according to degree of adherence to the following dietary patterns: overall low-carbohydrate, animal-based low-carbohydrate, and high-vegetable low carbohydrate. They then compared death rates between the highest and lowest adherence groups for each pattern.
The authors’ conclusions: A low-carbohydrate diet rich in animal foods was associated with a 23% increased risk of death from all causes (14% increased risk of death from cardiovascular disease). In contrast, a low-carbohydrate diet rich in vegetables was associated with a 20% decreased risk of death from all causes (23% decreased risk of death from cardiovascular disease).
The low-carb proponents had one thing right: the avoidance of refined carbohydrates – white flour, white rice, white pasta, added sugars, etc. are disease-promoting foods. However, the protein sources emphasized in most low-carb diets are micronutrient-poor animal products rather than micronutrient-packed plant products. The current study suggests that plant sources of protein (for example vegetables, nuts, beans, and seeds) promote longevity, whereas high protein animal foods have the opposite effect. This data supports the essential nutritional concept I illustrate with my health equation: Health = Nutrients / Calories. Micronutrient density determines the quality of one’s diet, and since animal products are deficient in micronutrients, they should be minimized. The authors agree that their results likely reflect the lack of protective fiber, minerals, vitamins, and phytochemicals in animal products. 
Many proponents of meat-based diets argue that the refined carbohydrate rather than the meat content of the American diet is to blame for our skyrocketing rates of chronic disease. However, too many studies contradict this opinion – and this study clearly demonstrates that choosing plant foods instead of animal foods, even within the context of minimal refined carbohydrate, promotes longevity.
There really should not be any controversy anymore about the health effects of low-carb, high-protein diets. This study (among others) confirms that the current amount of animal-source foods within the American diet should be reduced, not increased, and that meat-centered diets promote premature death; and that diets based predominantly on whole plant foods are lifespan-enhancing.
The “nutritarian” diet I recommend is unique because it focuses on consuming more of the highest micronutrient containing vegetation, as it reduces animal products to a condiment or minimal role held to less than 10 percent of total calories. Vegetables rule!
1. Foster, G.D., et al., Weight and metabolic outcomes after 2 years on a low-carbohydrate versus low-fat diet: a randomized trial. Ann Intern Med, 2010. 153(3): p. 147-57.
2. Brinkworth, G.D., et al., Long-term effects of a very-low-carbohydrate weight loss diet compared with an isocaloric low-fat diet after 12 mo. Am J Clin Nutr, 2009. 90(1): p. 23-32.
3. Sacks, F.M., et al., Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates. N Engl J Med, 2009. 360(9): p. 859-73.
4. Sinha, R., et al., Meat intake and mortality: a prospective study of over half a million people. Arch Intern Med, 2009. 169(6): p. 562-71.
5. Vergnaud, A.C., et al., Meat consumption and prospective weight change in participants of the EPIC-PANACEA study. Am J Clin Nutr, 2010. 92(2): p. 398-407.
6. Zheng, W. and S.-A. Lee, Well-Done Meat Intake, Heterocyclic Amine Exposure, and Cancer Risk. Nutrition and Cancer, 2009. 61(4): p. 437-446.
7. Key, T.J., et al., Mortality in vegetarians and nonvegetarians: detailed findings from a collaborative analysis of 5 prospective studies. Am J Clin Nutr, 1999. 70(3 Suppl): p. 516S-524S.
8. Ashaye, A., J. Gaziano, and L. Djousse, Red meat consumption and risk of heart failure in male physicians. Nutr Metab Cardiovasc Dis, 2010.
9. Snowdon, D.A., R.L. Phillips, and G.E. Fraser, Meat consumption and fatal ischemic heart disease. Prev Med, 1984. 13(5): p. 490-500.
10. Aune, D., G. Ursin, and M.B. Veierod, Meat consumption and the risk of type 2 diabetes: a systematic review and meta-analysis of cohort studies. Diabetologia, 2009. 52(11): p. 2277-87.
11. Fung TT, v.D.R., Hankinson SE,Stampfer M, Willett WC, Hu FB, Low-Carbohydrate Diets and All-Cause and Cause-Specific Mortality: Two Cohort Studies. Ann Intern Med, 2010. 153(5): p. 289-298.
12. Fiore, K. Low-Carb Diet is Better When Rich in Veggies. 2010 September 7, 2010]; Available from: http://www.medpagetoday.com/PrimaryCare/DietNutrition/22035.