By Dennis Thompson
And it's all for naught.
Folks are heavier than ever despite all this effort, reports a new study.
The proportion of people who've tried to lose weight during the previous year increased to 42% in 2015-2016, up from 34% in 1999-2000, according to federal survey data.
At the same time, body mass index (BMI) and weight for the average American also increased:
Average BMI went up to 29.4 in 2015-2016, just under the obesity level at 30. In 1999-2000, average BMI was 28.
People tipped the scales at an average 184 pounds in 2015-2016, compared to 176 pounds in 1999-2000, according to the survey of about 48,000 adults. Ages ranged from 40 to 64.
"Where weight-loss efforts are increasing, we can expect a decreasing trend of obesity, but it is not decreasing," said senior researcher Dr. Lu Qi, director of the Tulane University Obesity Research Center in New Orleans.
Why is this happening? It might be that people are trying to diet but aren't pursuing it in an effective manner, Qi said.
For example, eating less is the most popular weight-loss strategy, with nearly one-third of people trying it, researchers found.
But people appear to be substituting fattening foods into their diet even as they cut back on the amount they eat, Qi said.
"People reported reducing their food intake, but when we analyzed the calorie intake, there's no decreasing trend," Qi said. "Even the people who report their food intake, they didn't reduce their calorie intake, which is key to weight loss."
However, other experts believe these numbers point to a fundamental flaw in the American strategy of weight loss.
"There's one obvious conclusion we can draw -- the way we have been told as a population to lose weight doesn't work," said Dr. Lee Kaplan, director of the Obesity, Metabolism and Nutrition Institute at Massachusetts General Hospital in Boston.
Eating less and exercising won't work long-term because your body regulates how much fat it carries, and that regulation is outside your personal control, Kaplan said.
"Obesity is a disease where the body thinks it needs more fat than is healthy," Kaplan said.
Dr. Mitchell Roslin, chief of obesity surgery at Lenox Hill Hospital in New York City, agreed. He noted that "detailed research clearly shows that eating less and exercising more are not effective for long-term weight loss."
"They proliferate and add to the frustration and stress of afflicted individuals," Roslin said of these strategies. "Humans can only eat less for short periods. Exercise is vital for wellness but not weight loss."
Human bodies are programmed to carry a certain amount of fat to keep us healthy, much in the same way the body automatically regulates the amount of water or blood it contains, Kaplan said.
That's why when we lose weight during an illness, we regain those pounds. "The first thing that will happen when you recover from the flu is you're going to gain that 10 pounds back," Kaplan said.
"Most people focus on the physics of weight. They always talk about the laws of thermodynamics and energy in and energy out," he said. "They don't realize that on top of the physics, the body cares how much fat it has.
"Merely eating less is not doing anything. Merely eating less is just telling the part of the brain that regulates this that you are sick," Kaplan continued. "And what does the brain do when you're sick and lose weight? It puts it back on for you."
Eating right is important for other reasons, including keeping your heart healthy and avoiding diabetes.
But a true cure for obesity is going to require medications or therapies that help readjust the body's self-regulation of fat, Kaplan said.
He compared the situation to that of treating epilepsy, high blood pressure or high cholesterol -- all conditions that medical science previously thought could be voluntarily regulated by people without the need for drugs or therapies.
"Once you recognize this is biology, then you need a biological and medical solution," Kaplan said. "We're working toward that."
The study findings are in the Nov. 13 JAMA Network Open.