Obese Mice Refuse to Move, Even if They Can -- Scientists Unveil Big Mystery Behind Weight Gain

We may have to take that New Year's resolution about dieting and exercising a bit more seriously. But if you feel a bit bored when it comes to the moving part, scientists may be starting to understand why.

Alexxai Kravitz from the National Institutes of Health in the US discovered in a study that changes in brain chemistry after we start gaining weight actually blunt our capacity to move. 

Scientific American reports that Alexxai Kravitz, a neuroscientist from the National Institutes of Health, discovered in his study that obese mice can move just fine. They just choose not to.

Kravitz and his team found the activity of a particular dopamine receptor that is linked to movement. It goes down as mice gain weight on a high-fat diet, meaning mice slow down and move less. And when they restored the activity of that receptor, the mice started moving more even if they're still obese.

According to Health Day, Kravitz and his team also discovered that lean mice missing the certain DR2 receptor acted like their obese counterparts and not move as much. This means this particular receptor serves as the therapeutic target, and that people can get moving if that DR2 receptor is restored. 

Stat News says the scientists also fed normal mace and the DR2-deficient mice the same high-fat diet, meaning they gained weight in the same right. The DR2 mice move less on the get-go, whereas a normal mouse will take more time before they actually refuse to move.

Meaning, the ability to exercise is disconnected from weight gain. Kravitz added that while exercise is a healthy thing to do, its impact on weight has been overstated. Though people have to keep in mind that it may take 20-30 years before we can do this to humans.

Keep in mind that the study was also done on a high-fat diet, and not the normal calorie-restricted diet people do when maintaining weight. The fat in the diet may be dampening DR2, not the weight gain.

This can be a big drawback. Vicki Viera-Potter, a University of Missouri physiologist not involved in the study, said the high-fat diet may be impairing the receptor and decrease activity. High-fat diets are a good way to induce obesity, but it's not the same thing.