For those grappling with weight loss despite consistent exercise, recent scientific findings may offer some clarity. Researchers have identified a crucial metabolic factor that may inhibit fat burning during physical activity, alongside reduced oxygen consumption, potentially leading to weight gain, obesity, and diabetes. This breakthrough suggests new avenues for combating obesity beyond appetite-suppressing medications.
The Role of PGC-1⍺ Variants in Fat Burning
The study, conducted by Kobe University, focused on a signal molecule called PGC-1⍺. This molecule exists in multiple forms, including the “b” and “c” variants, which significantly increase in muscle tissue during exercise—over ten times more than the “a” variant. The team, led by endocrinologist Ogawa Wataru, proposed that these “b” and “c” molecules play a vital role in energy metabolism during workouts.
Experimental Insights from Mice and Humans
To test their hypothesis, researchers engineered mice that lacked the “b” and “c” signal molecules, relying solely on the “a” variant. They assessed muscle growth, fat burning, and oxygen consumption during rest, short-term exercise, and extended workouts. Parallel experiments were conducted with human volunteers, including individuals with and without type 2 diabetes, to measure similar parameters.
Key Findings
The study revealed that mice without the “b” and “c” molecules struggled to adapt to short-term physical activity, resulting in reduced oxygen consumption and fat burning during and post-exercise. Human subjects displayed consistent results, with both healthy and diabetic individuals consuming more oxygen and having lower body fat correlating with higher “b” and “c” protein levels.
Interestingly, long-term exercise showed benefits even for those producing only the “a” protein. Mice that engaged in regular exercise developed more muscle over six weeks, regardless of their ability to produce the “b” and “c” variants.
Impact of PGC-1⍺ on Cold Response
Further research indicated that the PGC-1⍺ protein variants also affect responses to cold. In cold environments, mice producing the “b” and “c” proteins burned more fat to maintain body temperature, whereas those without these proteins experienced significant temperature drops.
Implications for Obesity Treatment
These findings underscore the importance of the “b” and “c” protein variants in responding to various stimuli, such as exercise and cold exposure. According to the research team, enhancing the production of these variants could revolutionize obesity treatment by increasing energy expenditure without relying on dietary restrictions.
“Recently, anti-obesity drugs that suppress appetite have been developed and are increasingly prescribed in many countries around the world,” Ogawa and his team noted. “However, there are no drugs that treat obesity by increasing energy expenditure. If a substance that increases the ‘b’ and ‘c’ versions can be found, this could lead to the development of drugs that enhance energy expenditure during exercise or even without exercise. Such drugs could potentially treat obesity independently of dietary restrictions.”
The complete study is available in Molecular Metabolism, and the researchers are now investigating how the “b” and “c” proteins increase in muscles during exercise.
