Exercise plays a key role in losing weight, but some people seem to lose it more easily than others, and a new study that highlights subtle differences in a class of molecules involved in metabolism may help explain why.
The molecule in question is a protein called PGC-1⍺, which is involved in the breakdown of carbohydrates and fats. A link between exercise and body weight has been pointed out in the past, but the mechanism and process by which this occurs have remained unclear.
In this new study, a team of experts from across Japan discovered that multiple variants of PGC-1⍺ are indeed involved, and that it is these variants, PGC-1αb and PGC-1αc, that actually confer the benefits of exercise and weight loss.
Kazuhiro Nomura, a biomedical scientist at Kobe University, and his team found that increased expression of mutant PGC-1αb and PGC-1αc genes in mice in response to exercise sent signals to other parts of the body to increase energy output.
The team tested mice and 10 male subjects on a treadmill and a stationary bike, respectively, and then took small tissue samples to understand what was happening in terms of muscle metabolism, fat burning and oxygen consumption.
To specifically test for the production of PGC-1α, we bred mice lacking the PGC-1αb and PGC-1αc proteins. Mice that did not receive the protein became obese and had excessive levels of insulin in their blood.
In a human study, researchers included a group of men classified as insulin intolerant, a condition known to reduce PGC-1α levels. They found that exercise increased levels of both PGC-1αb and PGC-1αc, resulting in the body’s metabolism functioning more efficiently.
These findings suggest that the ability to produce PGC-1αb and PGC-1αc may have some connection to the ease with which one can maintain weight, a finding the scientists had expected based on previous research.
“The hypothesis that skeletal muscle genes determine susceptibility to obesity was correct,” says Wataru Ogawa, an endocrinologist at Kobe University.
As with any new discovery, the results of this finding are not entirely clear, so future studies are needed to explore these processes in larger, more diverse groups of people.
But it does give us new clues as to why the ratio of exercise to weight loss isn’t the same for everyone. No doubt many factors are at play, but if we can artificially control the activity of PGC-1αb and PGC-1αc in the future, it could lead to entirely new types of weight loss treatments.
“If we can find a substance that increases beta and C types, it could lead to the development of drugs that increase energy consumption both during exercise and without exercise,” says Ogawa.
“Such drugs could potentially treat obesity independently of dietary restriction.”
This study was published in the journal Molecular Metabolism.
