Wednesday, March 03, 2010

A tale of two abstracts

I've kindly re written the abstract for the high fat, low carbohydrate vs semi starvation paper by Eckel's group of clowns in Colorado. I've not attempted to re-title it as the current title needs to be discarded rather than corrected. Especially describing a non significant rise in LDL cholesterol as "hypercholesterolaemia" is not simply incorrect, it is completely dishonest. These people are, like Black's group in Belfast, not stupid. They're just bent.

The original:

Background: Little is known about the comparative effect of weight-loss diets on metabolic profiles during dieting. Objective: The purpose of this study was to compare the effect of a low-carbohydrate diet (<20 g/d) with a high-carbohydrate diet (55% of total energy intake) on fasting and hourly metabolic variables during active weight loss. Design: Healthy, obese adults (n = 32; 22 women, 10 men) were randomly assigned to receive either a carbohydrate-restricted diet [High Fat; mean +/- SD body mass index (BMI; in kg/m2): 35.8 +/- 2.9] or a calorie-restricted, low-fat diet (High Carb; BMI: 36.7 +/- 4.6) for 6 wk. A 24-h in-patient feeding study was performed at baseline and after 6 wk. Glucose, insulin, free fatty acids (FFAs), and triglycerides were measured hourly during meals, at regimented times. Remnant lipoprotein cholesterol was measured every 4 h. Results: Patients lost a similar amount of weight in both groups (P = 0.57). There was an absence of any diet treatment effect between groups on fasting triglycerides or on remnant lipoprotein cholesterol, which was the main outcome. Fasting insulin decreased (P = 0.03), and both fasting (P = 0.040) and 24-h FFAs (P < 0.0001) increased within the High Fat group. Twenty-four-hour insulin decreased (P < 0.05 for both groups). Fasting LDL cholesterol decreased in the High Carb group only (P = 0.003). In both groups, the differences in fasting and 24-h FFAs at 6 wk were significantly correlated with the change in LDL cholesterol (fasting FFA: r = 0.41, P = 0.02; 24-h FFA: r = 0.52, P = 0.002). Conclusions: Weight loss was similar between diets, but only the high-fat diet increased LDL-cholesterol concentrations. This effect was related to the lack of suppression of both fasting and 24-h FFAs.

Corrected version:

Background: Much is known about the comparative effect of weight-loss diets on metabolic profiles during dieting, though our research group seem peculiarly ignorant of the literature. Objective: The purpose of this study was to compare the effect of a low-carbohydrate diet (<20 g/d) with a high-carbohydrate diet (55% of total energy intake) on fasting and hourly metabolic variables during active weight loss. Design: Healthy, obese adults (n = 32; 22 women, 10 men) were randomly assigned to receive either a carbohydrate-restricted diet which was unrestricted in calories or fat and was consumed to satiation [High Fat; mean +/- SD body mass index (BMI; in kg/m2): 35.8 +/- 2.9] or a severely calorie-restricted, low-fat diet (High Carb; BMI: 36.7 +/- 4.6) for 6 wk. A 24-h in-patient feeding study was performed at baseline and after 6 wk. Glucose, insulin, free fatty acids (FFAs), and triglycerides were measured hourly during meals, at regimented times. Remnant lipoprotein cholesterol was measured every 4 h. Results: Patients lost a similar amount of weight in both groups (P = 0.57), the excess weight loss in the calorie and fat unrestricted High Fat diet not reaching statistical significance. There was an absence of any diet treatment effect between groups on fasting triglycerides or on remnant lipoprotein cholesterol, which was the main outcome. Fasting insulin decreased (P = 0.03) only in the High Fat diet, and both fasting (P = 0.040) and 24-h FFAs (P < 0.0001) increased within the High Fat group, as is appropriate for a fatty acid based metabolic profile. Twenty-four-hour insulin decreased (P < 0.05 for both groups), the decrease within the High Fat group being twice that seen in the High Carb group. Fasting LDL cholesterol decreased in the High Carb group only (P = 0.003), representing an increase in the atherogenic sdLDL particle subgroup. In both groups, the differences in fasting and 24-h FFAs at 6 wk were significantly correlated with the change in LDL cholesterol (fasting FFA: r = 0.41, P = 0.02; 24-h FFA: r = 0.52, P = 0.002). Conclusions: Weight loss was similar between diets despite unrestricted calories and fat intake in the High Fat group. The high-fat diet did not significantly increase LDL-cholesterol concentrations (P = 0.13). High Fat diets increase LDL lipoprotein size non significantly, potentially decreasing atherogenicity, which is possibly related to the increase in both fasting and 24h FFAs.


Peter

6 comments:

crisismaven said...

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Ed said...

Let me guess, they didn't measure Lp(a). An we predict a significant rise in the high carb group.

Peter said...

Hi Ed, look at it the other way round, they did significant damage with the HC diet and the liver then makes Lp(a) to patch up the dietary booboo. But yes, Lp(a) will have gone up (and would have gotten the blame if they had measured it). You might have guessed that there is more coming on Lp(a)!

Crisismaven,

Hi. That's a bit overwhelming. My stats knowledge is limited to spotting idiocity in duff studies! But I will bear you site in mind...

Peter

Valtsu said...

Hiya! My post goes a bit off-topic, but here is another stupid abstract I've found. But nothing very interesting though...

http://www.nutritionandmetabolism.com/content/5/1/36

Abstract:
"Diabetes medications were reduced or eliminated in 95.2% of LCKD vs. 62% of LGID participants (p < 0.01)."

Full-text:
"At baseline, 22 (75.9%) of the LGID group were taking hypoglycemic medications (insulin only n = 3, oral agents only n = 19), and 20 (95.2%) of the LCKD group were taking hypoglycemic medications (insulin + oral agents n = 4, insulin only n = 4, oral agents only n = 12). Twenty of 21 (95.2%) LCKD group participants had an elimination or reduction in medication, compared with 18 of 29 (62.1%) LGID group participants (p < 0.01)."

blogblog said...

Last night I saw an amazing documentary called Contact about the last group of Australian aborigines to be "civilised".

The year was 1964. Twenty pre-contact aboriginal women and children were located by patrol officers and encouraged to join their relatives on a mission.

These traditional aborigines lived entirely on small game and a few wild plants. The women were all as thin as ballerinas with perfect teeth when first ecountered.

Forty-five years of western carbohydrate-laden mission food has made all these aborigines grossly obese with atrocious teeth and (almost certainly) diabetic.

Peter said...

Blogblog, I guess that's the way it goes on non-food carbohydrate....

Peter