In a new study, researchers show that neurons controlling hunger and appetite in the brain also control the “browning” of white fat.
That discovery suggests that modulating this connection may be a new way to fight obesity.
Previous research showed that energy-storing white fat has the capacity to transform into energy-burning “brown-like” fat.
This process impacts how much energy we burn and how much weight we can lose.
Excess fatty tissue is a major risk factor for type 2 diabetes, cardiovascular disease, hypertension, neurological disorders, and cancer. People become overweight and obese when energy intake exceeds energy expenditure, and excess calories are stored in the adipose tissues.
The adipose organ is made up of both white and brown fat. While white fat primarily stores energy as triglycerides, brown fat dissipates chemical energy as heat.
The more brown fat you have, the more weight you can lose.
The team stimulated this browning process from the brain in mice and found that it protected the animals from becoming obese on a high-fat diet. The team then studied the molecular changes in hunger-promoting neurons in the hypothalamus and found that the attachment of a unique sugar called “O-GlcNAc” to potassium ion channels acts as a switch to control brain activity to burn fat.
“Our studies reveal white fat ‘browning’ as a highly dynamic physiological process that the brain controls,” says lead author Xiaoyong Yang, associate professor of comparative medicine and physiology at Yale School of Medicine.
“This work indicates that behavioral modifications promoted by the brain could influence how the amount of food we eat and store in fat is burned.”
Yang says hunger and cold exposure are two life-history variables during the development and evolution of mammals.
“We observed that food deprivation dominates over cold exposure in neural control of white fat browning. This regulatory system may be evolutionarily important as it can reduce heat production to maintain energy balance when we are hungry.
“Modulating this brain-to-fat connection represents a potential novel strategy to combat obesity and associated illnesses.”
The National Institutes of Health, American Diabetes Association, Ellison Medical Foundation, American Heart Association, and CNPq/Brazil funded the work, which appears in Cell.