Joined: Jul 12
Posted: 05 Jul 2012, 14:17
Always review medical publications directly, not through the unreliable medium of internet journalism, any scientist or physician will agree that spin, positive or negative, can distort the findings of studies. Grab a dictionary if you find the science babble difficult to navigate.
"In contrast, the very low-carbohydrate diet had the most beneficial effects on energy expenditure and several metabolic syndrome components, but this restrictive regimen may increase cortisol excretion and CRP. The low–glycemic index diet appears to have qualitatively similar, although smaller, metabolic benefits to the very low-carbohydrate diet, possibly without the deleterious effects on physiological stress and chronic inflammation. These findings suggest that a strategy to reduce glycemic load rather than dietary fat may be advantageous for weight-loss maintenance and cardiovascular disease prevention. Ultimately, successful weight-loss maintenance will require behavioral and environmental interventions to facilitate long-term dietary adherence. But such interventions will be most effective if they promote a dietary pattern that ameliorates the adverse biological changes accompanying weight loss."
In short, this study does support the Low-Carb diet, HOWEVER, this study had only 21 subjects, making broad conclusions dubious. Still more studies need to be completed to get concrete results, until then one should plan their diet at their own discretion.
Joined: Dec 10
Posted: 05 Jul 2012, 14:23
I disagree that this study "supports low carb dieting." If anything, you can argue that the study supports the opposite conclusion.
Even though the authors claimed to find a greater TDEE post-weight-loss with the low carb diet compared to low-fat and low-GI, this did not translate into any difference in actual weight.
In other words: calories were held constant during the crossover trials, and lo and behold weight remained constant, despite a supposed TDEE advantage of over 320 calories/day. That's over 9100 calories over 4 weeks, or a supposed advantage of 5600 calories over the low-GI diet.
And yet, there was no statistically significant difference in the subjects' weights* (in fact, weights were very slightly higher on VLC than on low-GI, despite the supposed 200 calorie/day advantage).
It's possible that with longer crossover trial periods, this supposed advantage would have materialized in an actual difference in weight, but until that is demonstrated, it's just as (if not more) likely that there was no metabolic advantage, and the differences in TDEE just reflect inaccuracy in the indirect measurement methods.
And getting back to my original point - if the subjects had the same amount of calories under each of the 3 diets, and the same activity level, yet remained weight stable despite burning over 320 calories/day more on one of the diets - you can just as easily argue that VLC dieting somehow interferes with weight loss, since that group should have been several pounds lighter, between the >9000 calorie difference in addition to the water weight loss that accompanies low-CHO while hypocaloric. I don't think that conclusion is any more justified than what Taubes claims, however.
Finally, even if the measured differences in TDEE were accurate, they varied greatly by subject. For some, their highest TDEE was observed during the low-fat diet. For others, it was during the low-GI diet. IF there is a difference in adaptive thermogenesis based on dietary composition, some people would apparently be worse off with a low-CHO protocol.
* "Body weight did not differ significantly among the 3 diets (mean [95% CI], 91.5 [87.4-95.6] kg for low fat; 91.1 [87.0-95.2] kg for low glycemic index; and 91.2 [87.1-95.3] kg for very low carbohydrate; P = .80)"
Joined: Mar 10
Posted: 05 Jul 2012, 15:44
My takeaway (while I agree this is a very limited study) was the moderate low GL index diet was likely the more 'optimal'. While it was the middle of the road regarding numbers...in the long run, it did not allow the increased production of Cortisol the way the VLC diet did, and the low fat diet was the worst.
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