News in brief February 3rd, 2014
Obésité et cancer de la thyroïde : association épidémiologique et mécanismes sous-jacents. (Obesity and thyroid cancer: epidemiologic associations and underlying mechanisms). Pazaitou-Panayiotou K, Polyzos SA, Mantzoros CS. Obes Rev. 2013 oct
Obesity may possibly be associated with thyroid cancer. It leads to hypoadiponectinemia, a pro-inflammatory state, and insulin resistance, which in turn can result in high circulating insulin and IGF-I levels, which are liable to increase the risk of thyroid cancer. Insulin resistance in particular may play a key role in this chain of causal events because of its interconnections with IGF-I, cytokines and TSH.
Relation quantitative entre le gain de poids chez l’adulte et l’incidence du diabète de type 2 : une méta-analyse. (Quantitative relationship between body weight gain in adulthood and incident type 2 diabetes: a meta-analysis.) Kodama S, Horikawa C, Fujihara K, Yoshizawa S, Yachi Y, Tanaka S, Ohara N, Matsunaga S, Yamada T, Hanyu O, Sone H. Obes Rev. 2013 Oct 25
Weight gain and initial weight may have additional effects on the risk of type 2 diabetes. In particular, gaining weight between the age of 18 and 24 may contribute more to the development of diabetes than gaining weight in mid-life. The risk of type 2 diabetes is increased three-fold by gaining 5 extra BMI points between the age of 18 and 24, versus two-fold when this weight gain occurs in mid-life.
Effet levier des protéines sur l’apport énergétique. (Protein leverage and energy intake). A. K. Gosby, A. D. Conigrave, D. Raubenheimer, S. J. Simpson. Obesity Rev 28 OCT 2013.
A balanced diet means keeping a certain ratio of protein to carbohydrate and fat. Increasing evidence has become available, however, that the protein content of people’s diet is on the decrease these days. These data suggest that a general loss of protein appetite may account for the current epidemic of obesity. More specifically, subjects whose diet lacks proteins tend to compensate for this shortage by greatly increasing their food intake, and hence their calorie consumption levels. In short, in order to consume sufficient amounts of protein, people are eating more calories than in the past.
Un quart de la perte de poids est composée de masse maigre : examen critique et analyse de cette croyance commune. (Weight loss composition is one-fourth fat-free mass: a critical review and critique of this widely cited rule.) Heymsfield SB, Gonzalez MC, Shen W, Redman L, Thomas D. Obes Rev. 2014 Jan 22.
It is generally believed (in line with Forbes’ rule) that one quarter of the weight lost by dieting consists of fat-free mass. In fact, less fat-free mass than this is lost by dieting: the fraction depends on the composition of the diet, the amount of energy consumed, gender, initial weight, whether or not regular exercise is prescribed, the subjects’ metabolic state and their hormonal responses. The model developed by Thomas (which is available free of charge via http://pbrc.edu/research-and-faculty/calculators/fat-free-mass/) can be used to assess the lean mass lost during the second weight-reduction phase (after the fast weight loss which occurs during the first few days) in subjects on a low-calorie diet associated or not with physical exercise.
Restriction calorique versus alimentation standard chez des sujets en surpoids, nouvellement diagnostiqués pour un cancer de la prostate : un essai randomisé contrôlé. (A study of caloric restriction versus standard diet in overweight men with newly diagnosed prostate cancer: a randomized controlled trial.) Wright JL, Plymate S, D'Oria-Cameron A, Bain C, Haugk K, Xiao L, Lin DW, Stanford JL, McTiernan A. Prostate. 2013 Sep;73(12):1345-51.
Obesity is known to be an aggravating factor for prostate cancer. In a preliminary study, overweight and obese men recently diagnosed with prostate cancer benefited in several ways from a 6-week low-calorie diet: they lost weight, their eating habits improved and the serum biomarkers (IGF-BP3) used to monotor the progression of their prostate cancer decreased.