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.