The number of people with obesity has nearly tripled since 1975, resulting in a worldwide epidemic. While lifestyle factors like diet and exercise play a role in the development and progression of obesity, scientists have come to understand that obesity is also associated with intrinsic metabolic abnormalities. Now, researchers from University of California San Diego School of Medicine have shed new light on how obesity affects our mitochondria, the all-important energy-producing structures of our cells.
In a study published January 29, 2023 in Nature Metabolism, the researchers found that when mice were fed a high-fat diet, mitochondria within their fat cells broke apart into smaller mitochondria with reduced capacity for burning fat.
Further, they discovered that this process is controlled by a single gene.
By deleting this gene from the mice, they were able to protect them from excess weight gain, even when they ate the same high-fat diet as other mice.
“Caloric overload from overeating can lead to weight gain and also triggers a metabolic cascade that reduces energy burning, making obesity even worse,” said Alan Saltiel, PhD, professor in the Department of Medicine at UC San Diego School of Medicine.
“The gene we identified is a critical part of that transition from healthy weight to obesity.”
Obesity, which affects more than 40% of adults in the United States, occurs when the body accumulates too much fat, which is primarily stored in adipose tissue.
Adipose tissue normally provides important mechanical benefits by cushioning vital organs and providing insulation.
It also has important metabolic functions, such as releasing hormones and other cellular signaling molecules that instruct other tissues to burn or store energy.