Sunday, August 15, 2010

Low Carb or Low Fat Equally Effective in Weight Loss, BUT Only Low Carb Favorably Changes in Cardovascular Disease

A paper by Foster (Foster. 2010) in the Annals of Internal Medicine reviews the outcomes of a 2-years dietary intervention employing low carb vs. low fat diets.

Fig. 1: Predicted absolute mean change in body weight for participants in the low-fat and low-carbohydrate diet groups, based on a random-effects linear model. (Foster. 2010. Fig.2)
The interesting result, which is also clearly visible in the data shown in Fig. 1 was that
there were no differences in weight, body composition, or bone mineral density between the groups at any time point. (Foster. 2010)
Although the low carb dieters reported overall more side effects (esp. in the course of the first 6 months) the low carb diet delivered favorable changes in cardivascular disease which have not been observed in the group of the low-fat dieters:
During the first 6 months, the low-carbohydrate diet group had greater reductions in diastolic blood pressure, triglyceride levels, and very-low-density lipoprotein cholesterol levels, lesser reductions in low-density lipoprotein cholesterol levels, and more adverse symptoms than did the low-fat diet group. The low-carbohydrate diet group had greater increases in high-density lipoprotein cholesterol levels at all time points, approximating a 23% increase at 2 years. (Foster. 2010)
Lesson to learn: Watch that carbs, but don't fall for the Ketogenic Diet, which is completely different from the approach taken in this study, where participants consumed a "low-carbohydrate diet", which consisted of limited carbohydrate intake (20 g/d for 3 months) in the form of low–glycemic index vegetables with unrestricted consumption of fat and protein", and, afterwards, to increased their carbohydrate intake (5 g/d per wk) until a stable and desired weight was achieved.