When you burn a lot of calories, your muscles start listening to a fat-burning signal
Severe energy deficit upregulates leptin receptors, leptin signaling, and PTP1B in human skeletal muscle.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When people burned a huge number of calories for a few days, their muscles started showing more signs of a hormone (leptin) that helps burn fat — especially in the arms. But another protein (PTP1B) that blocks this signal also went up.
Surprising Findings
PTP1B increased by 45% during recovery—even though participants were no longer in a calorie deficit.
It’s counterintuitive that the body’s fat-burning brake would ramp up after the stressor ends, suggesting a delayed overcompensation mechanism that could hinder long-term weight maintenance.
Practical Takeaways
If you're doing an extreme short-term cut, prioritize upper-body workouts to potentially enhance fat-burning signals in your arms.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When people burned a huge number of calories for a few days, their muscles started showing more signs of a hormone (leptin) that helps burn fat — especially in the arms. But another protein (PTP1B) that blocks this signal also went up.
Surprising Findings
PTP1B increased by 45% during recovery—even though participants were no longer in a calorie deficit.
It’s counterintuitive that the body’s fat-burning brake would ramp up after the stressor ends, suggesting a delayed overcompensation mechanism that could hinder long-term weight maintenance.
Practical Takeaways
If you're doing an extreme short-term cut, prioritize upper-body workouts to potentially enhance fat-burning signals in your arms.
Publication
Journal
Journal of applied physiology
Year
2017
Authors
I. Perez‐Suarez, J. Ponce-González, Jaime de la Calle-Herrero, J. Losa-Reyna, Marcos Martin‐Rincon, D. Morales‐Alamo, A. Santana, H. Holmberg, J. Calbet
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Claims (5)
Even though the body starts using leptin better to burn fat during extreme dieting, it also makes more of a protein (PTP1B) that normally blocks leptin—like the body is both stepping on the gas and the brake at the same time.
When the body is in extreme calorie deficit, the arms respond more strongly to fat-burning signals than the legs—possibly because the legs make more of a protein that blocks those signals.
Eating whey protein during extreme dieting might reduce the muscle’s fat-burning response to leptin, compared to eating sugar—but this isn’t proven yet.
When people burn a lot more calories than they eat for a few days, their muscles start responding more to a hormone called leptin, which helps them burn fat better—especially in the arms.
Muscles with more slow-twitch fibers (used for endurance) tend to have stronger leptin signaling during extreme dieting, suggesting these fibers are better at switching to fat-burning mode.