Obese people may have a harder time losing weight compared to thin people because their brains appear to be wired differently for impulse control, according to a new study published in the Journal of Clinical Investigation.
Researchers from Yale University and the University of Southern California took what seems like a small sample of people – five obese people and nine non-obese people – and manipulated their blood sugar levels and monitored their brain activity with functional MRI scanners.
The study participants were shown pictures of high-calorie foods such as French fries and doughnuts, low-calorie foods such as tofu and salads, and non-foods.
When their blood sugar was low, all study participants showed activity in the region of the brain associated with reward, meaning they all wanted that doughnut (or other high-calorie food).
But something interesting happened when blood sugar levels were brought up to normal.
The non-obese group showed increased activity in the region of the brain associated with impulse control. But that was not true for obese people in the study. Their brains continued to desire high-calorie foods.
"This is significant for the obesity epidemic, as it shows for the first time that obese individuals may have a particularly hard time restraining themselves when faced with high-calorie foods and food cues in the environment, and that they are at greater risk for giving in and consuming high-calorie foods," Rajita Sinha, co-author of the study, told ABC News.
The study also sheds more light on how important blood sugar levels are when it comes to anyone who is trying to lose weight, since even non-obese people ached for doughnuts when their levels were down.
"My advice to people trying to lose weight is to eat frequent, small healthy meals and small snacks so that glucose doesn't significantly drop," said Robert Sherwin, co-author of the study. "If you wait until after lunch to have your first meal, your blood sugar is going to drop so much that it's going to drive you to keep eating."
Do you find it hard to resist the temptation of high-calorie French fries and doughnuts?
Dave McGinn