Childhood Obesity Theory Challenged After 42 Years

Topic: Health

A new study suggests that a long-held theory about why children's body mass index (BMI) increases after age 6 may be wrong. The research, led by Professor Andrew Agbaje, found that the rise in BMI is likely due to normal muscle growth, not a rebound in fat.

New findings challenge a 42-year-old theory about why children's body mass index (BMI) declines after infancy and then begins climbing steadily from about age 6. The pattern has long been described as the "adiposity rebound," based on the idea that body fat first decreases and then returns.

However, the new analysis suggests that the later increase in BMI is not caused by a rebound in fat. Instead, it may largely reflect the normal growth of muscle and other lean tissue. The research, led by Professor Andrew Agbaje, a physician and associate professor of clinical epidemiology and child health at the University of Eastern Finland, Kuopio, Finland, was presented at this year's European Congress on Obesity in Istanbul, Turkey and published in The Journal of Nutrition.

The concept dates back to 1984, when French researcher Marie Françoise Rolland-Cachera and her colleagues described "adiposity rebound" in a paper published in The American Journal of Clinical Nutrition. Since then, some physicians have treated the pattern as a meaningful warning sign that might be prevented or modified through diet and lifestyle changes.

Why It Matters

This study has important implications for childhood health care. If the rise in BMI is actually a normal result of muscle development, efforts to stop it may be addressing a problem that does not exist. This could lead to better decision-making by parents, caregivers, and healthcare professionals about how to promote healthy growth in children.

Key Facts

• The "adiposity rebound" theory has been challenged after 42 years.
• Professor Andrew Agbaje led the research at the University of Eastern Finland.
• The study was presented at the European Congress on Obesity in Istanbul, Turkey.
• The concept of "adiposity rebound" dates back to 1984.
• A new analysis suggests that muscle growth, not fat rebound, is behind the rise in BMI.

Key Terms

BMI

Body Mass Index, a measure of body fat based on height and weight

Adiposity Rebound

The theory that children's BMI declines after infancy and then begins climbing steadily from about age 6

Implications

This study has important implications for childhood health care. If the rise in BMI is actually a normal result of muscle development, efforts to stop it may be addressing a problem that does not exist. This could lead to better decision-making by parents, caregivers, and healthcare professionals about how to promote healthy growth in children.