a friend sent me this German article and asked for my opinion:
it's just too funny, so I wanna share it with you guys. if you have further arguments debunking this study, please share!
here you find the paper: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone....
excerpt from the original paper's abstract:
Sixteen adults with metabolic syndrome (age 44.9±9.9 yr, BMI 37.9±6.3 kg/m2) were fed six 3-wk diets that progressively increased carbohydrate (from 47 to 346 g/day) with concomitant decreases in total and saturated fat. Despite a distinct increase in saturated fat intake from baseline to the low-carbohydrate diet (46 to 84 g/day), and then a gradual decrease in saturated fat to 32 g/day at the highest carbohydrate phase, there were no significant changes in the proportion of total SFA in any plasma lipid fractions. Whereas plasma saturated fat remained relatively stable, the proportion of palmitoleic acid in plasma triglyceride and cholesteryl ester was significantly and uniformly reduced as carbohydrate intake decreased, and then gradually increased as dietary carbohydrate was re-introduced. The results show that dietary and plasma saturated fat are not related, and that increasing dietary carbohydrate across a range of intakes promotes incremental increases in plasma palmitoleic acid, a biomarker consistently associated with adverse health outcomes.
so, first of all, it's a piot study on 16 people...... yeah sure, totally invalidates previous research such as the china study on considerably larger sample sizes....
next, I checked the affiliations...
Funding: This work was funded by a grant from Dairy Research Institute, The Beef Checkoff, the Egg Nutrition Center, and the Robert C. And Veronica Atkins Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Partial funding for Open Access provided by The Ohio State University Open Access Fund.
Competing interests: Professional associations (Dairy Research Institute, The Beef Checkoff and the Egg Nutrition Center) were sponsors of this research. This does not alter the authors' adherence to PLOS ONE policies on sharing data and materials.
the previous paragraph pretty much explains the findings in my unbiased opinion :P
my motivation to take it seriously dropped immediately.
so please, help me debunk this paper with solid arguments!
just look at the p=values in table 3.
a significant p-value is something like 0.05 (5% chance that the result is due to chance rather than the controlled change)
here, we have a p-value of 0.489 for some measurements! so, there are 50% chance to have this result and 50% chance to find the opposite. what can you conclude with that???
we can conclude what the funders want we conclude. how convenient!
thank you, Nicolas!
good point! I hadn't even read the table. however, you must admit, they also have some significant values, even in the ANOVA.
this led me to something else. baseline was measured after 3 weeks 'run-in period', and only then the 'feeding' was started. so baseline should rather be called low-carb-line.
Prior to the 18-wk controlled feeding intervention, subjects were counseled to consume a 3-wk very low-carbohydrate run-in diet that mirrored the first low-carbohydrate feeding phase (C1, ~50 g carbohydrate/day) in order to initiate metabolic adaptations to carbohydrate restriction. Three-day diet records were utilized to determine nutrient intake prior to baseline and during the run-in diet.
This study seems to just validate the results they decided upon before doing it. One of the most noticeable issues is the usual problem, their low fat diet is not a low fat diet. They only reduced saturated fat to 32g a day not to mention there was probably plenty of other fats still present. Carbs were only ever at 350g a day, I eat twice that many carbs. So essentially the 16 sick individuals remained sick throughout the entire study.
It seems like you can form a study to validate any opinion at this point.
you're so right!!! I was actually gonna have a look at this but got too distracted by the Beef Checkoff...
and you're right... it's so sad! why do they even get published, and in a peer-reviewed magazine on top of that??!
We don't really know what they were fed:
For each diet phase 7-day rotational menus were developed that included a wide range of whole foods. Beef, eggs, and dairy were used daily throughout all diet phases as primary sources of saturated fat. For the low carbohydrate diet phases, higher-fat beef and meats, whole eggs, and full-fat dairy products (e.g., cheese, whole milk yogurt, cream, butter) were emphasized. For the higher carbohydrate diet phases with lower saturated fat, leaner versions of beef, egg substitutes, and low-fat dairy (e.g., reduced-fat dairy, skim milk, low-fat/non-fat yogurt) were used instead. Whole grain and relatively low glycemic index carbohydrate sources were emphasized.
3 phrases to tell about the fat and 1 for the carbs.
What means relatively low glycemic index? When we know what they consider a low-fat diet...
I think the biggest problem is the short length of the study..