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.
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Systematic Reviews & Meta-Analyses
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Max 72Case-Control Studies
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Evidence Score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
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.
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Systematic Reviews & Meta-Analyses
Max 100Randomized Controlled Trials
Max 90Cohort Studies
Max 72Case-Control Studies
Max 58Cross-Sectional Studies
Max 44Case Reports & Case Series
Max 30Expert Opinion & Narrative Reviews
Max 531 / 72
Evidence Score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Publication
Authors
Perez-Suarez I, Ponce-González JG, de La Calle-Herrero J, Losa-Reyna J, Martin-Rincon M, Morales-Alamo D, Santana A, Holmberg HC, Calbet JAL
Related Content
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.