Obesity: Fat Chance Without Fat

23. March 2016
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Low carbohydrate, low fat, or, even better, doing without meat? Popular diets are to found a dime a dozen. From a scientific perspective, the evidence on their side is very poor everywhere. When patients change their habits in the long term, off come the pounds.

According to World Health Organisation (WHO) estimates, more than half a billion people are overweight. Those affected, measured in terms of turnover of their daily consumption, take in too much storable energy. In addition to environmental factors such as having office jobs, little free time and diet sins, genes play a central role. Mutations in FTO or TRIM28 with epigenetic regulaton are considered to be associated with obesity. These findings do not currently help sufferers. In the event of having BMI values of more than 40 or perhaps 35 in combination with other diseases, experts advise bariatric surgery. Otherwise, there remains the option of looking at countless diet programs. An overview of recent publications shows what scientists think about them.

Low Carb knocks out Low Fat

For a long time fat was considered by diet gurus to be the villain par excellence. Proteins and carbohydrates with their significantly lower energy densities seemed to be more appropriate food sources. In the long term, low-fat diets did not lead to the desired result, Deirdre K. Tobias and Frank B. Hu, Boston, found out. They were indeed inferior to a standard diet by a difference of 5.41 kilograms. Under a low carbohydrate diet regime, subjects lost 1.15 kg more than with low-fat diet.

Lydia A. Bazzano and Tian Hu, New Orleans, come to similar results by way of a randomised, controlled comparative study involving 148 subjects. All participants had no previous illnesses. They were assigned to two groups randomly. Low-carb-diets contained 40 grams of carbohydrates per day. With low-fat-programs fat was not to exceed 30 percent of total energy. There was no specific calorie target. Adherence was relatively high, being 80 percent after twelve months in both groups, due to keeping regular contact with doctors and nutritionists. After this time those seeking to slim-down had under a lowcarb regime lost 5.3 kg of weight; under a low fat regime this figure was only 1.8 kilograms. Significant differences were not found by scientists when looking at LDL-levels, but when looking at C-reactive protein and triglycerides levels, based on the Framingham Risk scores, they found that low-carb programs were associated with significantly lower cardiovascular risks.

Endless stream of red cards

Renée Atallah, Montreal, has delved into four popular programs, namely the Atkins, Zone, Weight Watchers And South Beach Diets. Twelve randomised controlled trials were used as references. Compared to a control group with only general dietary recommendations or alternative diets only the Weight-Watchers Diet won points. However, many subjects had regained much of their lost weight, to be precise from 3.5 to 6.5 kilograms, two years after the start. In one comparative study the Atkins Diet fared excellently, while other studies assessed this form of diet rather poorly. All in all Atallah established no clear favourite.

Advantage for the meatless

There has until the present been no clear answer to the question of whether vegetarian diets reduce body weight. Ru-Yi Huang from Taiwan and Jorge E. Chavarro from Boston tried therefore to shed light on this matter by way of a meta-analysis. They found twelve randomised controlled trials involving 1,151 participants and various diet concepts throughout public data bases. Those who fed themselves on a vegetarian diet lost an average of 2.02 kg more than subjects in which meat and fish were on the menu. Pure vegan lifestyles brought the number on the scales down by another 2.52 kg, compared with ovo-lacto vegetarians. Those who counted kilojoules and limited their energy intake were pleased to find approx 2.21 kg less padding on their ribs. In the absence of calorie restriction, this figure was only 1.13 kg. Huang and Chavarro are certainly of the opinion that a vegetarian way of life can facilitate slimming. However, this meta-analysis does not manage to say anything about long-term impacts.

Hitting goals in the long term

Experts also think little of supposed panaceas such as interval fasting, detox diets, the paleo diet or the HCG diet. In one statement, the German Society for Nutrition (DGE) criticised several weak points. On one hand, lack of scientific evidence existed in relation to the desired effect. On the other hand, patients would not manage to succeed in changing their habits in the long term.

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3 comments:

Anthony Murawski
Anthony Murawski

Just a follow-up… I have no opinion about the efficacy concerning approaches mentioned here that are not supported by “evidence-based medicine.” My comment is of a general nature. Mr. Anthony Murawski

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Dr Anthony Murawski
Dr Anthony Murawski

I don’t quite agree with the analogy, but I do I agree that “lack of scientific evidence exist[s] in relation to the desired effect” is a weak argument against checking to see whether an intervention works for someone. If there are reasons to question the safety of a medical or lifestyle choice, then I take that into account. But “lack of scientific evidence” often means that there is no huge profit to be made, so the lack of research simply means that the health managment approach in question hasn’t piqued the interests of researchers who get the massive amount of funding needed to conduct large-scale, double-blind studies.

So much of large-scale, “evidence-based” research is essentially fraudulent. Much of the published medical literature is conducted on behalf of pharmaceutical companies by researchers under contract with explicit (and surreptitious) instructions to minimize real risks and to distort data to create the false appearance of benefits, claiming “significant”results in abstracts that are available for free, but defining “significant”as something truly questionable — in the range of a 30% response rate –in full journal articles that newspaper reporters do not read, which most people can’t afford to purchase, and which almost no clinicians ever look at (since most of them don’t even look at the free abstracts). And the unsuccessful clinical trials do not get published, although I believe that if federal funds are involved, there should be a requirement that the data from those trials be made public, and that if federal funds are not involved, an announcement of the fact that an unsuccessful trial took place, with enough data available for meaningful analysis, should be required and made public by a journal before it publishes the “successful” clinical trial results that are subsequently reported by pharmaceutical companies.

This is just the tip of the iceberg. How many people (including medical clinicians and pharmacists) know, for instance, that since the early 1980s, the regulatory agencies that are supposed oversee vaccine manufacturers have very often received royalties from the sales of the vaccines they regulate, and that the public isn’t even permitted to know the amount in profits that these agencies receive, because that information is withheld under the pretext of “trade secret” protection? This isn’t a conspiracy theory. It is encoded in federal legislation under 15 USC § 3710a and 15 USC § 3710c.

“Evidence-based medicine” is a doctrine intended in part to perpetuate the absurd notion if a medical intervention is clearly successful on a routine basis in a clinical setting, that evidence should be outright ignored, because insurance companies want to pay as little as possible for treatment, and because blockbuster, money-making alternatives become less necessary.

Doctors rely on “anecdotal evidence” every time they make a clinical decision; but that very same kind of evidence is thrown out the window when discussing treatment options, instead of being scrutinized for confounding factors while recognizing that correlation is not necessarily causation, and while also using basic common sense to understand that humans rarely require absolute proof to understand when a true causal relationship exists. If we did require that kind of proof, nobody would survive past the age of 7.

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Kristijan Kulonja
Kristijan Kulonja

“Watch out! There’s a tree in front of you!” “Oh, I’m not convinced. There’re no such evidence based studies done yet to prove that assumption!”… After a second: “Boom, crash, trash…”

The absence of evidence is NOT the evidence of absence!

‘Paleo’ works for so many of us, because it’s written in our genes, in our evolution!

Kristijan Kulonja, MD

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