Estimated read time: 2-3 minutes
This archived news story is available only for your personal, non-commercial use. Information in the story may be outdated or superseded by additional information. Reading or replaying the story in its archived form does not constitute a republication of the story.
SALT LAKE CITY — The complexity of losing weight and staying thin may have more to do with how bodies burn calories than previously thought, a new study suggests.
Researchers at Kent State University recently completed a study using laboratory rats to show the effects of aerobic activity on muscles. The study’s authors worked to determine the relationship between genetics, exercise and weight gain or loss.
“A high-calorie diet accompanied by low levels of physical activity accounts for the widespread prevalence of obesity today, and yet some people remain lean even in this obesogenic environment,” the study states. “Here, we investigate the cause for this exception.”
The researchers looked at the overall body mass and muscle structure of individual rats and compared how lean rats and obese rats differed in terms of the speed of calories burned.
It was discovered that rats with leaner body mass burned calories faster than those with higher mass. The cause for this, according to the study, is the composition of the muscle structure of leaner rats compared to the heavier rodents.
Using sets of 25 females rats of varying leanness and weights, the researchers were able to determine the leaner rats had elevated levels of proteins while energy was expended and lower levels of protein stored during more sedentary periods, according to an article in healthline.com.
Genetics can be overcome.
–Colleen Novak
“The muscles will use energy to move us around. But in some cases muscles can be less efficient at this," researcher Colleen Novak told Healthline. "The energy can’t disappear, though. In the case of muscles, it is dissipated as heat. That is why you get hot when you exercise.”
The researchers concluded that individuals with leaner body mass have a propensity to burn calories more rapidly at rest than heavier individuals. Novak said she believes genetics plays a large role in this dichotomy, but is not absolute when determining weight.
"In the bigger picture, (the study) would also imply that any advantage these intrinsically lean people have in staying thin may be canceled out if they are not physically active," she told Healthline.
"Genetics can be overcome," Novak said.
The study, titled "Leanness and heightened nonresting energy expenditure," was originally published in the American Journal of Physiology.
