Because of how chemical reactions inside our brains differ, overweight people may feel a greater compulsion to track down the source of a delicious smelling pizza and consume it than their lean counterparts.

A National Institutes of Health study looked at how 43 people of different shapes and sizes react to food cues.

The study found that overweight people may overeat more frequently but recieve less satisfaction from their eating. This is because people who are overweight experience higher levels of dopamine activity in the habit forming regions of their brains whereas but also experience less activity in the region of the brain that controls reward.

“This means that triggers, such as the smell of popcorn at a movie theatre or a commercial for a favourite food, may have a stronger pull for an obese person – and a stronger reaction from their brain chemistry – than for a lean person exposed to the same trigger,” says study leader Kevin D. Hall, Ph.D.

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