Many people believe that in order to lose weight, a combination of diet and exercise usually accomplishes that goal. However, one researcher claims that eating less is much more important than just exercising constantly.
In a report published by the New York Times, pediatrics professor Aaron E. Carroll of the Indiana University School of Medicine argued that reaching and maintaining a healthy weight requires a person to consider the amount of food consumed as opposed to placing "overwhelming emphasis on exercise."
"Exercise consumes far fewer calories than many people think," Carroll wrote. "Thirty minutes of jogging or swimming laps might burn off 350 calories. Many people, fat or fit, can't keep up a strenuous 30-minute exercise regimen, day in and day out. They might exercise a few times a week, if that."
Carroll added that people could also reduce 350 calories "by eliminating two 16-ounce sodas each day." He acknowledged that exercise has many benefits, but there were problems when it is used to control weight.
"From 2001 to 2009, the percentage of people who were sufficiently physically active increased. But so did the percentage of Americans who were obese," Carroll wrote. "The former did not prevent the latter."
A 2011 study conducted by PLOS One looked at the relationship between physical activity and fat mass in children. The result, which was from a meta-analysis, or a study of studies, drew a surprising conclusion.
"The result suggests no association," PLOS One wrote. "Objectively measured physical activity may not be the key determinant of unhealthy weight gain in children."
According to Carroll, "interventional studies" also held up that assertion for the adult population in the United States. He also looked at "studies of energy balance."
"Further, studies of energy balance, and there are many of them, show that total energy expenditure and physical activity levels in developing and industrialized countries are similar, making activity and exercise unlikely to be the cause of differing obesity rates," Carroll wrote.
Carroll asserted that the notion of exercise increasing one's appetite was true. That's because, according to Carroll, one's body signals replacement of calories burned off by physical activity.
"A 2012 systematic review of studies that looked at how people complied with exercise programs showed that over time, people wound up burning less energy with exercise than predicted and also increasing their caloric intake," Carroll wrote.
Carroll observed that changes in metabolism can negatively affect weight loss benefits achieved through exercise in the long term. That's because metabolism "often slows" when weight loss happens.
"Many people believe that exercise can counter or even reverse that trend," Carroll wrote. "Research, however, shows that the resting metabolic rate in all dieters slows significantly, regardless of whether they exercise. This is why weight loss, which might seem easy when you start, becomes harder over time."
However, Carroll admitted that exercise can play a "statistically significant, but overall small" role when added with diet. Two different studies seemed to reinforce that notion.
"All of these interventions included dietary changes, and the added weight-loss benefit from activity was small," Carroll wrote.
Carroll emphasized that exercise had its own benefits, particularly when it came to improving "outcomes in musculoskeletal disorders, cardiovascular disease, diabetes, pulmonary diseases, neurological diseases and depression." When it came to losing weight, however, Carroll asserted that "gradual change" conducted in a "much more sustainable way" had the best chance of success.
"I also don't mean to make it seem that weight loss with diet is easy and exercise is hard. They're both hard," Carroll wrote. "The challenge of a slowing metabolism, and the desire to eat more, occurs in both cases, although dietary change still works better than exercise."