There is no doubt among health prof

There is no doubt among health professionals that healthier life-style and improved general nutrition would have the greatest positive impacts on obesity related diseases. Besides a sedentary life style, the amount of food consumed and the nature of carbohydrates and lipids used in Western foods have most often been blamed for the current obesity epidemics. But it has been difficult to predict how individual dietary components would affect the pattern of fat accumulation in the body and obesity related diseases. It has for instance been almost impossible for experts in the field to predict, based on best available knowledge in biochemistry and physiology, that consumption of fructose-sweetened, but not glucose-sweetened, beverages would promote dyslipidemia and lead to increased visceral adiposity and decreased insulin sensitivity in obese humans (K. L. Stanhope et al. Consuming fructose-sweetened, not glucose-sweetened, beverages increase visceral adiposity and lipids and decrease insulin sensitivity in overweight/obese humans. J CHn. Invest. 2009; 119 (5):1322-1334). The current knowledge on what is determining the pattern of fat accumulation inside the body has first and foremost been developed as a result of experience. This applies also to the accumulating evidence for a correlation between obesity related diseases and the ratio of n-6/n-3 fatty acids in dietary lipids. When this ratio is too high, such as it is in Western diets, the impacts on human health are negative (A. P. Simpoulos. The importance of the Omega-6/Omega-3 Fatty Acid Ratio in Cardiovascular Disease and Other Chronic Diseases. Society for Experimental Biology and Medicine 2008; 674-688; G. Ailhaud et al. An emerging risk factor for obesity: does disequilibrium of polyunsaturated fatty acid metabolism contribute to excessive adipose tissue development? British Journal of Nutrition 2008; 100:461-470), in particular if a high proportion of the n-6 fatty acids in the diet consists of the "essential fatty acid" linoleic acid (Cl 8:3 n-6).