UCPs belong to the family of mitochondrial transporter proteins that play an essential role in energy balance and thermogenesis. UCPs separate oxidative phosphorylation from ATP synthesis with energy released as heat or during aerobic activity. UCP1 is mostly expressed in brown fat. Genetic variants alter the activity or expression of the UCPs, which may decrease basal energy expenditure by varying the coupling of oxidative phosphorylation and impacting pancreatic functions and insulin secretion.
UCP1, in particular, plays an important role in reducing the production of oxidative stress in the mitochondria, which in turn can predispose you to certain lifestyle-related chronic diseases such as obesity and/or type 2 diabetes. The UCP genes are considered candidate genes for obesity, insulin resistance, and type 2 diabetes.
The GG genotype or variation is linked to a potential for reduced basal energy expenditure, weight gain, and weight loss resistance.