Low-carbohydrate diets make you lean and healthy, systematic review shows

Thursday, August 30, 2012 by: Eric Hunter
Tags: low-carb diet, body fat, healthy

(NaturalNews) The amount of research on low-carbohydrate diets have skyrocketed the last couple of years; mostly due to the increased popularity of carbohydrate restriction and the "overwhelming" amounts of anecdotal reports from people following these types of diets. Individuals who adhere to a low-carbohydrate eating style usually get most of their calories from fat, and skeptics often argue that the increased consumption of meat and saturated fat will "clog the arteries" and increase the risk of disease. A new meta-analysis, a systematic review of studies, found that low-carbohydrate diets lead to weight loss and improved health.

A low-carbohydrate diet usually involves reduced consumption of grains, legumes, rice, certain dairy products and sometimes fruits and root vegetables. Fat becomes the main source of energy, and avocado, coconut products, oils, full-fat dairy, meat, fish, fowl, eggs, olives etc., are common food staples.

The exact amount of carbohydrates in different types of "low-carbohydrate" diets usually range from 0-100 grams.

The systematic review of low-carbohydrate diets used 23 reports that met the criteria of the analysis; which includes 17 clinical investigations and a total of 1,141 obese patients. Low carbohydrate diets were found to be associated with significant decreases in body weight, blood pressure, insulin levels and plasma C-reactive protein. In general, low-carbohydrate diets were found to improve all cardiovascular risk factors. Weight loss in itself also contributes to improved metabolic markers.

Low-carbohydrate diets will not clog your arteries

The link between saturated fat, cholesterol and heart disease has long been considered an established connection by many medical professionals. However, when looking into the human physiology and biomedical literature, one quickly realizes that it's not so cut and dry. Several comprehensive reviews conclude that low-carbohydrate diets don't increase the risk of heart disease and cardiovascular disease.

The new systematic review also showed that low-carbohydrate diets cause an increase in HDL, the "good" cholesterol, and no significant changes in LDL, the "bad" cholesterol. It's also known that the majority of people can eat cholesterol without it affecting their cholesterol levels. Rather than elevated blood cholesterol, inflammation seems to be the major cause of heart disease.

This doesn't mean that a low-carbohydrate diet is necessarily the optimal diet

The benefits of these systematic reviews are that they look at several reports, rather than just presenting the data from one study. This way it's possible to get a larger picture and be able to draw more accurate conclusions. However, this meta-analysis gives little information about the effects of low carbohydrate diets compared to other popular diets, the exact amount of carbohydrate necessary to achieve good results and which foods to choose.

Sticking to a low-carbohydrate diet usually means increased consumption of paleolithic foods and reduced consumption of processed foods, grains, legumes, milk and other western foods staples.
These "modern" foods often have a high-carbohydrate density and contain several anti-nutrients, problematic proteins and hormones. Thereby, avoiding these foods results in reduced inflammation and a healthier life.

Epidemiological studies show that humans can maintain excellent health when eating a high-carbohydrate diet based on fruits, berries, nuts and root tubers and other vegetables.

The one group of people that "always" benefits from carbohydrate restriction is overweight and obese individuals. All of the available literature shows that low carbohydrate diets are linked to significantly more weight loss compared to other diets. Overweight and obesity usually go hand in hand with low-level chronic inflammation, insulin resistance and leptin resistance. Carbohydrate restriction usually improves insulin and leptin resistance among other things, thereby contributing to weight loss.


Sources for this article include

Santos FL, Esteves SS, da Costa Pereira A, et al. Systematic review and meta-analysis of clinical trials of the effects of low carbohydrate diets on cardiovascular risk factors.
Obes Rev. 2012 Aug 21. doi: 10.1111/j.1467-789X.2012.01021.x. [Epub ahead of print]

Mente A, et al. A systematic review of the evidence supporting a causal link between dietary factors and coronary heart disease.Arch Intern Med. 2009 Apr 13;169(7):659-69.

Hooper L, et al. Reduced or modified dietary fat for preventing cardiovascular disease.Cochrane Database Syst Rev. 2011 Jul 6;(7):CD002137.

Siri-Tarino PW, et al. Meta-analysis of prospective cohort studies evaluating the associationof saturated fat with cardiovascular disease. Am J Clin Nutr. 2010 Mar;91(3):535-46.

Kratz M, et al. The relationship between high-fat dairy consumption and obesity, cardiovascular, and metabolic disease. European Journal of Nutrition, Online First?, 18 July 2012