Hypothalamus is different in people who are overweight

Cambridge scientists have shown that the hypothalamus, a key region of the brain involved in controlling appetite, is different in the brains of people who are overweight and people with obesity when compared to people who are a healthy weight. The researchers say their findings add further evidence to the relevance of brain structure to weight and food consumption.

They used an algorithm developed using machine learning to analyse MRI brain scans taken from 1,351 young adults across a range of BMI scores, looking for differences in the hypothalamus when comparing individuals who are underweight, healthy weight, overweight and living with obesity.

In a study published today in Neuroimage: Clinical, the team found that the overall volume of the hypothalamus was significantly larger in the overweight and obese groups of young adults. In fact, the team found a significant relationship between the volume of the hypothalamus and body mass index (BMI).

These volume differences were most apparent in those sub-regions of the hypothalamus that control appetite through the release of hormones to balance hunger and fullness. While the precise significance of the finding is unclear – including whether the structural changes are a cause or a consequence of the changes in body weight – one possibility is that the change relates to inflammation.

Reference: Brown, SSG, et al. Hypothalamic volume is associated with body mass index. Neuroimage: Clinical; 8 Aug 2023; DOI: 10.1016/j.nicl.2023.103478