Can lifestyle modifications such as eating less and avoiding fat-rich food and exercising alone be sufficient for obese people to shed weight and stay slimmer? Scientists do not think so.
“Obesity should be recognised as a chronic and an often treatment-resistant disease with both biological and behavioural causes,” says a Comment piece published today (February 12) in the journal The Lancet Diabetes & Endocrinology. And the only way to fight obesity is by regarding it as a “disease” that cannot be cured with frontline methods.
The reason why a majority of obese people struggle to shed weight in the first place and then maintain their weight once they have lost it is because bodyweight seems to be “biologically stamped in and defended.” Such is the tenacity of the biological adaptations that they persist indefinitely even after an obese person manages to shed weight through lifestyle changes.
These biological adaptations are seen only in obese persons. Even in them, the adaptations do not become imprinted until such time a person continues to remain obese for a certain period of time.
“As far as we can tell, these adaptations (such as, increased adipose cellularity) appear to occur only once someone has had obesity for an extended period of time before that weight becomes biologically stamped in. That amount of time will vary greatly between individuals, but may be as little as six months to one year,” Christopher N Ochner of the Mount Sinai Adolescent Health Center, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York told this Correspondent by email.
But once established, the biological adaptations have an insidious way of inducing increased calorie consumption and storage of fat to protect an individual’s highest sustained weight. And when an obese person loses weight, the biological adaptations kick in and become stronger to regain the lost weight. “The larger the gap between highest sustained lifetime weight and current weight, the stronger the biological pressure to regain the lost weight,” he explained.
Worse, even if an obese person manages to shed weight and remain trim, the obesity is said to be in a state of “remission,” and these people are biologically different from others of the same age and who have never been obese in the first place.
“Someone who formerly had obesity but was able to re-attain a healthy body weight by dieting will (as far as we can tell, likely forever) have to eat 200-300 fewer calories (or burn that many more calories) than someone who is the same age, sex and weight but never was obese. There are other potentially permanent changes in adipose cellularity and neural responsivity as well,” he said.
The only silver lining for the obese people is that 5-10 per cent weight-loss is sufficient to improve some of the medical biomarkers (for instance, blood pressure, insulin sensitivity) that are associated with body weight and obesity.
Though antiobesity drugs have been found to be effective, the long-term (over two years) risk-benefit ratio of these drugs is not known. According to Dr. Ochner, surgical interventions, when appropriate, are currently the only known way to produce significant weight-loss out very long-term (> 20 years) in severely obese people.
Of the all the surgical interventions, the gastric bypass surgery (Roux-en-X) is believed to produce healthy changes in appetite-related hormone profiles in severely obese people.
This underlines the need for overweight people to shed weight and never progress to an obese state.