In addition, it is unknown how poverty, food availability and physical activity interact with the diet. Carefully controlled metabolic studies have shown that unsaturated fats replaced by carbohydrate reduce blood levels of HDL cholesterol and increase triglycerides without reducing total or LDL cholesterol. This atherogenic lipid pattern is seen among nonobese people with activity patterns typical of urbanized populations. The following point has been made in defense of the recommendation to limit consumption of fatty foods. While low fat diets often fail to control or reverse obesity, this is no evidence that the initial accumulation of adipose tissue is not promoted by a high fat diet.
Adipose tissue is gained readily for survival and the new homeostasis is defended.
Attempts to loose weight result in metabolic and behavioral responses to defend the existing weight.