Inactivity Does Not Cause Obesity, Brain Malfunctioning Does

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We have often heard that high-fat food makes people feel sluggish and results in weight gain and obesity. Now, a new study has proved that the diet-induced obesity alters the functioning of our brain, and suppresses our natural impulse to move around or do physical exercise in any way.

A new study published by journal Cell Metabolism has found that in mice, obesity disrupts the proper functioning of dopamine receptor in the brain's striatum. Dopamine is a chemical in the brain which affects our moods, and our will to eat and do physical exercises. Striatum is the part of the brain that controls our movement and reward-seeking behavior.

The scientists fed some mice high-fat chow and fattened them up. They found that it reduced the activity of a specific class of dopamine receptor. With it, the fat mice adopted more sedentary behavior than their lean peers.

The scientists then suppressed the activity of that particular brain receptor in mice who were fed normal chow, and found that they too lost the impulse to run or move around their cages. However, they did not become obese.

Similarly, when the researchers 'turned up' the receptors in obese mice, they became more active.

Till now, it was thought that being inactive causes obesity. This study proves that excess weight can affect our brain in a way to make us sluggish, and make us gain more weight. Lack of exercise is also one of the major causes of obesity-related diseases such as Type 2 diabetes, high cholesterol, and hypertension.

The research also noticed that the excess weight changes our reward-seeking behavior related to physical activities. They noticed that while normal mice lived to run on a running wheel for hours, fattened up mice started avoiding it. A 2014 study published by the NCBI had earlier proved that multiple brain networks, including ventral and dorsal striatum, were associated with self-regulation of physical activity in human beings.

Perhaps, this new study can guide us how to modify the behavior of obese people and motivate them to lose their weight more effectively.