The science of energy balance investigates the path our brains keep our bodies on to prevent veering off into obesity. It’s a complex system that balances calories consumed with energy expended. New research about the details of energy balance seeks to provide a better understanding of how the brain controls appetite and the body burns calories.
A neurobiological conversation
The hypothalamus is only about the size of a pearl, but this region of the brain regulates homeostasis—the process of maintaining equilibrium among all the systems in the body. A key aspect of homeostasis is energy balance. The hypothalamus is engaged in constant communication with the body, receiving feedback on energy levels and controlling adjustments when energy balance is either positive (calorie surplus) or negative (calorie deficit).
Brown fat thermogenesis
Little is known about the details of this complex interchange, except the consequences when equilibrium is disrupted. In their efforts to learn more, researchers at Beth Israel Deaconess Medical Center in Boston have discovered how a neurotransmitter known as gamma-aminobutyric acid (GABA) regulates energy by controlling the rate brown fat burns energy to generate heat—a phenomenon known as thermogenesis.
According to the researchers, energy balance regulated by brown fat thermogenesis is critical in maintaining a healthy body weight and preventing diet-induced obesity. The new study, described in he October 26 issue of the journal Cell, investigated the neurobiological exhange driving thermogenesis.
Calorie burning interference
The researchers focused on a specialized cluster of neurons in a part of the hypothalamus called the arcuate nucleus. They genetically engineered mice with a defect that prevents the arcuate neurons from releasing GABA. Mice with this genetic defect had trouble burning calories and became markedly obese. Another group of mice engineered so GABA could be switched on and off, showed that burning calories normally was entirely dependent on GABA.
The results revealed that the rate brown fat burns calories was selectively driven by arcuate neurons in the hypothalamus through their release of GABA. This raises the possibility that new treatments for obesity could be developed with drugs that help restore energy balance by modifying how the hypothalamus controls energy expenditure with GABA.
Everyday energy balance
For most of us, our calories consumed and calories burned don’t need to be balanced on a daily basis. However, over time your lifestyle can help your hypothalamus maintain energy balance—and a healthy weight.
Think of energy balance as your “lifestyle budget.” For example, if you know you’re going to a party and may eat more than normal, eat fewer calories for a few days before so they balance out. Or exercise more those days to burn off the extra energy. Keep in mind that eating just 150 more calories a day than you burn can lead to an extra 10 pounds in a year.