Why doesn't the brain lose weight, when obese people diet?

Achim Peters*, Anja Bosy-Westphal, Britta Kubera, Dirk Langemann, Kristin Goele, Wiebke Later, Martin Heller, Christian Hubold, Manfred James Müller

*Corresponding author for this work
20 Citations (Scopus)


Objective: As has been shown recently, obesity is associated with brain volume deficits. We here used an interventional study design to investigate whether the brain shrinks after caloric restriction in obesity. To elucidate mechanisms of neuroprotection we assessed brain-pull competence, i.e. the brain's ability to properly demand energy from the body. Methods: In 52 normal-weight and 42 obese women (before and after 10% weight loss) organ masses of brain, liver and kidneys (magnetic resonance imaging), fat (air displacement plethysmography) and muscle mass (dual-energy X-ray absorptiometry) were assessed. Body metabolism was measured by indirect calorimetry. To investigate how energy is allocated between brain and body, we used reference data obtained in the field of comparative biology. We calculated the distance between each woman and a reference mammal of comparable size in a brain-body plot and named the distance 'encephalic measure'. To elucidate how the brain protects its mass, we measured fasting insulin, since 'cerebral insulin suppression' has been shown to function as a brain-pull mechanism. Results: Brain mass was equal in normal-weight and obese women (1,441.8 ± 14.6 vs. 1,479.2 ± 12.8 g; n.s.) and was unaffected by weight loss (1,483.8 ± 12.7 g; n.s.). In contrast, masses of muscle, fat, liver and kidneys decreased by 3-18% after weight loss (all p < 0.05). The encephalic measure was lower in obese than normal-weight women (5.8 ± 0.1 vs. 7.4 ± 0.1; p < 0.001). Weight loss increased the encephalic measure to 6.3 ± 0.1 (p < 0.001). Insulin concentrations were inversely related to the encephalic measure (r = -0.382; p < 0.001). Conclusion: Brain mass is normal in obese women and is protected during caloric restriction. Our data suggest that neuroprotection during caloric restriction is mediated by a competent brain-pull exerting cerebral insulin suppression.

Original languageEnglish
JournalObesity Facts
Issue number2
Pages (from-to)151-157
Number of pages7
Publication statusPublished - 01.04.2011

Research Areas and Centers

  • Academic Focus: Center for Brain, Behavior and Metabolism (CBBM)


Dive into the research topics of 'Why doesn't the brain lose weight, when obese people diet?'. Together they form a unique fingerprint.

Cite this