What role does LCT play in weight loss?

The LCT gene encodes lactase, the enzyme that breaks down lactose in dairy. Variants like rs4988235 determine lactase persistence (ability to digest milk in adulthood) or lactose intolerance. There is no strong, direct evidence that LCT variants play a causal role in weight loss. Some observational studies suggest that individuals with lactose intolerance may consume fewer dairy products, potentially reducing calorie intake, but this is not a reliable or recommended weight-loss strategy. Moreover, avoiding dairy can lead to inadequate calcium and vitamin D intake. Overall, the evidence is weak and mixed; weight loss is primarily driven by overall energy balance, diet quality, and physical activity, not by LCT genotype alone.