A common albeit inaccurate saying in nutrition is that a calorie is a
calorie. Put another way, many believe that restricting calories is all
that matters.
But a growing number of studies clearly show differences
between reducing fat versus carbohydrate. In respect to body
composition, convincing evidence of the importance of macronutrient
composition was presented in a comprehensive meta-regression of 87 diet
trials. The authors concluded that diets lower in carbohydrate were
associated with
greater fat loss and diets higher in protein resulted in better preservation of lean body mass during
weight loss.
Furthermore, these effects were independent of energy intake and
participation in exercise. A number of other studies have also shown
improvements in lipid profiles, glucose levels, and inflammatory
markers with low carbohydrate diets. The most recent study was
published by Volek and colleagues. They had 40 overweight men and women
consume either a low fat diet or a very low carbohydrate diet for 3
months. A broad spectrum of health markers were examined in addition to
weight loss and body composition. The low fat diet led to some weight
loss and improvement in metabolic indicators, but the low carbohydrate
diet did better on almost all counts. Weight loss and fat loss were
two-fold greater, and the improvements in blood levels of
triglycerides, HDL cholesterol, glucose, insulin, insulin sensitivity,
and several other emerging risk factors were significantly greater in
response to the low carbohydrate diet. This study provides strong
evidence showing how potent restricting carbohydrates can be for
promoting weight and fat loss and multitude of risk factors in
overweight subjects.
Volek
JS, Phinney SD, Forsythe CE, Quann EE, Wood RJ, Puglisi MJ, Kraemer WJ,
Bibus DM, Fernandez ML, Feinman RD. Carbohydrate Restriction has a More
Favorable Impact on the Metabolic Syndrome than a Low Fat Diet. Low
carbohydrate more effective than a low fat diet Lipids. 2009
Apr;44(4):297-309. Epub 2008 Dec 12.
