Exercise can play a crucial role in weight loss, but the strange thing is that some people lose excess weight more easily than others.
A new study sheds light on subtle differences in a class of molecules involved in metabolism, which may help explain why.
The molecule in question (a protein) is involved in the breakdown of carbohydrates and fats, and is called PGC-1⍺.
A team of Japanese experts has discovered that multiple variants of PGC-1⍺, most notably PGC-1αb and PGC-1αc, can make a difference in exercise and weight loss.
The research team ran tests on mice and 10 male humans, including treadmills and exercise bikes, then took small tissue samples to see what was happening in terms of muscle metabolism, fat burning and oxygen consumption.
Kobe University biomedical scientist Kazuhiro Nomura and his team found that if lab mice's bodies increased expression of the PGC-1αb and PGC-1αc variants in response to exercise, it sent a signal to the rest of the body to increase energy production.
The absence of PGC-1αb and PGC-1αc in mice was shown to cause obesity and increased insulin levels in the blood.
In human testing, the researchers found that levels of PGC-1αb and PGC-1αc were boosted by exercise, which in turn stimulated the body's metabolism more efficiently.
"The hypothesis that genes in skeletal muscle determine susceptibility to obesity was correct," says endocrinologist Ogawa Wataru of Kobe University in Japan.
The findings offer important insight into why exercise and weight loss are not the same for everyone.
If the activity of PGC-1αb and PGC-1αc can be artificially controlled in the future, a whole new set of weight loss therapies could be developed.
Future research should be conducted to study these processes in larger, more diverse groups of people.
The study was published in Molecular Metabolism.