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Is "metabolic damage" from dieting real?
"My metabolism is broken from dieting" is common online. The real phenomenon behind it is real, but far less permanent than the phrase implies.
What actually happens
Extended dieting does reduce metabolic rate below what body weight alone would predict — a real, measured phenomenon called adaptive thermogenesis, partly from losing body mass (which burns calories) and partly from hormonal and neurological adaptations that increase energy efficiency during a prolonged deficit.[1]
Why "damaged" is the wrong word
This adaptation is a normal, reversible survival response, not permanent damage to your metabolism — most of the drop recovers over weeks to months once calorie intake returns to maintenance, especially alongside resistance training to rebuild any lost muscle. What actually helps: reverse dieting (raising calories gradually rather than all at once) and prioritizing protein and strength training through and after a diet phase to preserve muscle mass, which is the biggest driver of metabolic rate you actually control.
Keep reading: BMR vs. TDEE · Cutting, bulking, and maintenance · Macros for fat loss