Mouse Study Provides Insight Into Weight Loss

Crowds of new faces at the gym and bare shelves of kale at the grocery store can only mean — it’s New Year’s Resolution time. Weight loss and increased exercise are common resolutions, but may be more difficult to achieve than you think.

Weight loss clues from mice

Researchers at the U.S. National Institute of Diabetes and Digestive and Kidney Diseases studied overweight mice to gain insight into why weight loss is so difficult for some. The study included feeding normal and high-fat diets to different groups of mice. The mice on the high-fat diet gained weight and did not display as much physical activity as those on normal diets. In addition, the overweight mice released less dopamine, a brain chemical that is essential for exercising. This signals that the brain may actually encourage inactivity in overweight people.

Other studies have linked dopamine to weight loss in terms of food consumption. This is is the first that aims to specifically connect it to exercise.

“Other studies have connected dopamine signaling defects to obesity, but most of them have looked at reward processing — how animals feel when they eat different foods,” researcher Alexxai Kravitz told HealthDay news. “We looked at something simpler: Dopamine is critical for movement, and obesity is associated with a lack of movement,”

Connection to humans

Obese man on motorized scooter at Lowes
Source: Wikimedia Commons

Researchers believe that the overweight mice had less capacity to receive and process dopamine. However, the resistance to physical activity started before the mice gained weight. This raises questions about how a change in diet might impact physical activity. The study also calls to question the relationship between willpower and weight loss.

“In many cases, willpower is invoked as a way to modify behavior,” Kravitz said. “But if we don’t understand the underlying physical basis for that behavior, it’s difficult to say that willpower alone can solve it.”

While mice can provide some insight into human behavior, they can’t give all of the answers. Additional research need to be conducted before any specific correlation to human weight loss can be drawn.
So, for now it’s probably best to stick with the plan of eating a healthy diet and hitting the gym in the new year.