Benefits associated with weight loss

Several benefits such as improved blood lipids, reduced risk of chronic disease, and positive psychological and quality of life effects are associated with weight loss.

       1- Effects on blood work

Several studies convincingly show that weight loss, secondary to an improvement in lifestyle, reduces blood pressure in hypertensive people or not with excess weight (National Institutes of Health, 1998), reduces plasma triglycerides (TG), increases good cholesterol (HDL), decreases bad cholesterol (LDL) and total cholesterol (Yu-Poth et al., 1999; National Institutes of Health, 1998; Dattilo and Kris-Etherton, 1992). Weight loss also reduces plasma glucose levels in overweight and obese people without diabetes, and improves blood sugar and glycosylated hemoglobin in some type 2 diabetic patients (National Institutes of Health, 1998).

2.      2- Effects on chronic disease and mortality

Being overweight is linked to increased morbidity and mortality for several diseases (National Institutes of Health, 1998). Nevertheless, the factors related to intentional or unintentional weight loss and the relationship between intentional weight loss and mortality have been little studied (Williamson, 1997). Prior to the 1990s, mortality studies made little distinction between intentional and unintentional weight loss (resulting from illness, loss of appetite, etc.). However, there is strong scientific evidence to suggest that weight loss in overweight or obese people would improve risk factors for diabetes and cardiovascular disease.

Singh et al (1992) reported the results of a randomized study, conducted in India, of the adoption of a cardioprotective diet in patients hospitalized with myocardial infarction. This study showed that, among those who lost at least 0.5 kg in weight, the risk of cardiac events was reduced by 50% and the risk of total mortality by 54%, compared to those who lost less than 0,5 kg after one year of follow-up.

Williamson et al. (1995) published the results of a 12-year, prospective observational study on weight loss and mortality based directly on the measurement of intention to lose weight. They analyzed data from 43,457 Caucasian women who were overweight (BMI over 27 kg / m2), non-smokers, and aged forty to sixty-four. In those with co-morbidities associated with obesity, intentional weight loss, regardless of the amount, was associated with a 20% decrease in all causes of mortality, primarily a significant 40% to 50% reduction in mortality by cancers linked to obesity. Mortality from diabetes was also reduced by 30% to 40%. On the other hand, in women without comorbidities, intentional weight loss was not associated with reduced mortality (National Institutes of Health, 1998). Thus, the authors conclude that the association between intentional weight loss and mortality depends on the health status of women who are overweight. Finally, some evidence suggests that intentional weight loss in overweight adult men is associated with a similar reduction in type 2 diabetes-related mortality, as observed in women (Williamson et al., 1999).

Thus, although very few studies have demonstrated a relationship between weight loss and mortality, improved risk factors for certain chronic diseases arising from weight loss strengthen the plausibility of such a link and suggest that development.

cardiovascular disease or type 2 diabetes may be prevented by weight loss (Esposito et al., 2004; National Institutes of Health, 1998; Stamler et al., 1997).