Losing weight is relatively easy, but keeping it off is the part where most people fail, said one of Canada's leading experts on obesity during a lecture in Sudbury Monday night.
Dr. Arya Sharma, chair of obesity research and management at the University of Alberta, told a crowd at Sudbury Secondary School that the vast majority of people who lose weight gain it back because they are losing a constant fight against their own body.
The people who manage to keep their weight down, after a weight loss of 40 lbs. or more, only consume around 1,500 calories per day, and burn 2,800 calories per week through daily exercise.
“If you stop doing exercise your weight goes right back to the top,” Sharma said.
Because human beings were hunter-gatherers for most our history, humans evolved to maintain fat reserves as a survival mechanism when food could be in short supply. A person's heaviest weight, Sharma said, becomes their “set weight.”
He said your body will work to preserve that set weight, and any deviation will be like pulling on a rubber band.
Once you stop pulling, by consuming fewer calories and exercising, your body reverts back to its set weight.
Sharma said yo-yo diets, where people get into a pattern of losing weight, gaining it back and losing it again, can be more dangerous than simply maintaining a heavier weight. There are people who are considered obese, he said, who are healthy in every other way.
He said obesity research is now exploring ways to loosen the “rubber band” a person must pull to escape their set weight.
Bariatriac surgery is one option that makes it easier for a person to tug on that rubber band and maintain a lower weight. This is because it reduces a person's appetite, and therefore, their calorie intake.
There are also environmental and social factors that contribute to obesity, Sharma said.
A lack of consistent sleep, for example, slows a person's metabolism.
Most Canadians, he said, also don't take enough time to eat. It takes around 20 to 40 minutes of eating for an average person to feel full. A slow eater will consumer fewer calories in that window, while a fast eater, consuming fast food, will take in more calories before their stomach tells them it is full.
Mental health issues, such as depression and attention deficit disorder, are also linked to obesity. Some people with severe depression use food as a coping mechanism.
“That's what makes obesity so complicated,” Sharma said. “There's not one problem.”
Any number of factors can cause obesity, and a person looking to lose weight, and keep it off, should see a professional to develop a plan that addresses their issues, Sharma said.
