How are BDNF and weight loss related?

BDNF (Brain-Derived Neurotrophic Factor) is a protein crucial for neuronal survival and plasticity, and it also plays a role in energy balance, appetite regulation, and metabolism. Lower BDNF levels are linked to obesity and metabolic syndrome, while weight loss—especially through diet and exercise—can increase BDNF concentrations. However, the relationship is bidirectional: BDNF influences body weight, and weight changes affect BDNF. Human studies show moderate effect sizes, and genetic variants like the Val66Met polymorphism in the BDNF gene are associated with small but consistent differences in body mass index. Consumer DNA tests may include BDNF-related SNPs, but their predictive power for weight loss success is limited. The evidence is based on observational and interventional studies, but causality is complex and multifactorial. Therefore, while BDNF is a relevant biomarker in the context of weight regulation, it should not be overinterpreted in isolation. A holistic approach considering diet, physical activity, and other genetic and environmental factors is essential. Evidence: human-moderate.