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Dietary fat is not the only explanation for the results.

Posted by chwarden on 23 Jul 2010 at 19:49 GMT

The authors of this manuscript do not adequately disclose the ingredients of their diets. They do not provide macronutrient composition of each diet (fat, protein, carbohydrate), nor do they reveal the types of fat, protein and carbohydrate used in each diet. Studies in humans have shown that the fructose component of sucrose promotes de novo lipogenesis [1]. This may be a crucial omission if one diet contains sucrose, while the other does not. Thus, the results may be due to the types of carbohydrates in the diet, not due to the use of a high-fat diet.
The second major problem with the conclusions of the study is that no comparison of a chow diet to a defined high fat diet can come to any conclusion about effects of specific ingredients because there are innumerable differences [2]. Thus, the only valid conclusion that can be reached from the present study is that diet influences fatty acid elongation in mice. Studies comparing and contrasting defined diets would be necessary if the authors wanted to conclude that fat amounts or type were responsible for effects on de novo lipogenesis.

1. Stanhope KL, Schwarz JM, Keim NL, Griffen SC, Bremer AA, et al. (2009) Consuming fructose-sweetened, not glucose-sweetened, beverages increases visceral adiposity and lipids and decreases insulin sensitivity in overweight/obese humans. J Clin Invest 119: 1322-1334.
2. Warden CH, Fisler JS (2008) Comparisons of diets used in animal models of high-fat feeding. Cell Metabolism 7: 277-277.


No competing interests declared.