The cause of obesity is not fully understood, although in recent decades the aetiology has become clearer as metabolic abnormalities have been researched in more detail. Irrespective of the causes, a large proportion of those individuals that attempt to lose weight through calories restriction and exercise fail to maintain permanent weight loss. Following treatment, around 50% of obese individuals have returned to their baseline weight within 3 to 5 years. Factors identified that increase the likelihood of successful weight loss include a longer duration of weigh maintenance, a smaller initial weight loss, lower levels of depressive symptoms and lower levels of disinhibition when being studied. Therefore successful weight gain results from both psychological and physiological factors and this adds a levels of complexity when trying to study the causes of and treatments for, obesity.
Researchers1 have investigated the incidence of weight regain amongst 2400 individuals in a prospective study over two years following a period of weight loss. Subjects lost an average of 32.1 kg over an average of 6.5 years and were then monitored for a further two years to assess weight regain. Two yeas after entry into the study, 96.4% of the subjects still remained 10% below their maximum lifetime weight. However, those who regained even small amounts of weight during this period were unlikely to lose it again. Regaining any weight in the first year was predictive of a relapse, and only 11% of these subjects managed to return to their baseline weight by year 2. Of the subjects who regained over 5% of their lost weight during the course of the 2 years, 95.3 failed to return to their baseline weight and 87.1% failed to lose even half of the weight gain by year 2.
These results suggest that for weight loss to be permanent, it is important that weight regain of any amount does not occur Those individuals who are able to prevent weight regain of even a small amount are much more likely to be successful in long-term weight loss. The researchers also performed logistical regression to assess the association between certain variables an the likelihood of weight regain. This revealed that those individuals who did not regain even small amounts of weight and those with smaller increases in depressive symptoms were much more likely to retain initial weight loss. Interestingly, adverse exercise and eating habit changes were not predictive of weight regain. This supports the growing body of evidence that suggests that obesity is far more complex than a simple energy balance equation and is a complex metabolic and psychological dysfunction.
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