Study overturns 42-year-old 'adiposity rebound' theory
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A study presented July 31 at the European Congress on Obesity overturns the 42-year-old 'adiposity rebound' theory, finding that the childhood BMI rise around age 6 stems from muscle growth, not fat rebound. The findings, led by Professor Andrew Agbaje of the University of Eastern Finland, suggest that what had been treated as an obesity warning sign is instead a normal developmental process.
The Adiposity Rebound Theory
The 'adiposity rebound' theory was first described in 1984 by French researcher Marie Françoise Rolland-Cachera in The American Journal of Clinical Nutrition. It posited that children's BMI declines after infancy to a low point around age 4, then begins a steady increase—a 'rebound'—reaching by age 6 the same level as at age 2. An early rebound, before age 5.5, was associated with greater adiposity at age 16, leading many pediatricians to treat the pattern as a modifiable warning sign for later obesity.
New Findings
Using a more precise measure of body composition, the study finds that the BMI increase around age 6 is not due to a rebound in fat mass. Instead, it largely reflects normal growth in muscle and other lean tissue. This challenges the very existence of an adiposity rebound, as body fat levels remain unchanged during this period. The study was published in The Journal of Nutrition.
Implications for Pediatric Care
The findings suggest that efforts to prevent or modify the adiposity rebound may target a non-existent problem. Since the rise in BMI is a normal part of muscle development, interventions based on the theory could be unnecessary. The research calls for a reassessment of how BMI trajectories in childhood are interpreted.
What's Next
The European Association for the Study of Obesity has not yet issued updated clinical guidance in response to the findings. It remains unclear how quickly pediatric practice will adapt to the new evidence, given the theory's 42-year legacy.
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Study overturns 42-year-old 'adiposity rebound' theory
