The biology of obesity #3

Continued from Saturday, Jan-29-11

Third in Series on Obesity Topic:

Carbs and protein

Increases in dietary carbohydrate and protein energy percentage will cause a reduction in dietary fat energy percentage, and vice versa. Epidemiological studies have suggested a positive association between fat-sugar ratio in the diet and BMI.8

With respect to the type of carbohydrates, intervention studies have indicated no differences in weight loss during intake of a low-fat diet rich in either simple or complex carbohydrates.9 However, there is evidence that high intake of simple carbohydrates in liquid form (soft drinks) may predispose to weight gain.10

Animal studies have indicated inverse relationships between dietary protein content and energy intake with between-strain differences in response, which suggest a nutrient-gene interaction.3 Intervention studies have suggested that a low-fat, high-protein diet may lead to a larger weight reduction compared with a low-fat, high-carbohydrate diet.11 Recent intervention studies suggest that low-carbohydrate, high-protein diets may be superior to the low-fat, high-carbohydrate diet in terms of weight reduction.12,13 However, large-scale intervention studies are required to determine long-term safety and efficacy of these dietary strategies for both prevention and treatment.

Dietary strategies

Several strategies exist for inducing weight loss in overweight and obese subjects. However, in most cases long-term success is limited because the majority of subjects regain all lost weight within three to five years. Obesity is a chronic condition, and it therefore seems evident that some form of life-long intervention may be needed in order to maintain weight loss in obese subjects. On the other hand, the long-term benefit of this strategy is not as obvious as it might look.

Thus, there is an ongoing debate regarding the evidence suggesting that weight reduction, although having beneficial effects on risk factors for cardiovascular disease and type 2 diabetes, may be associated with increased long-term mortality.14,15 Evidently, improved primary prevention of weight gain in obesity-prone subjects, combined with improved strategies for management of obesity, are the main tasks for the future.

Future large-scale, multi-disciplinary projects should aim at optimising the use of new research methods in combination with existing research methods. Metabolomics and proteomics, combined with gene expression profiling and genotype screening, may provide new important insights into the system biology of obesity. This may further allow the identification of candidate pathways involved in the development of obesity, and thereby the identification of candidate drug targets for treatment and prevention of obesity, as well as biomarkers indicating the efficiency of the pathways on the individual subject level.

It may be speculated that although a large number of genes and a complex interplay of environmental and genetic factors determines body fat accumulation, the number of pathways mediating the effect of these factors on body fat accumulation may be limited. Identifying the pathways could serve as a platform for a new classification, diagnostic and treatment of the common complex forms of obesity. Further, identifying biomarkers reflecting susceptibility to particular nutrients in pre-obese subjects would be a crucial step in the primary prevention of obesity.

Camilla Verdich, PhD, and TIA Sorensen, PhD, are at Copenhagen University Hospital, Denmark. Karine Clement, Fabienne Foufelle, PhD, and P Ferre are with INSERM, France, the French National Institute for Health and Medical Research. Excerpted from Functional Foods, Ageing and Degenerative Disease, C Remacle and B Reusens, editors. ISBN 0-8493-2538-2. Published by Woodhead Publishing Ltd, England.

http://www.woodheadpublishing.com

http://www.functionalingredientsmag.com/content/print.aspx?topic=the-biology-of-obesity

http://www.depsyl.com/

http://back2basicnutrition.com/

http://bionutritionalresearch.olhblogspace.com/