Rodent of the Week: Fat messes with your mind

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The brain is increasingly the target for understanding why people overeat and become obese. A new study, in rodents, shows that some forms of dietary fat apparently sabotage a system in the body that is designed to prevent overeating.

The study, from researchers at UT Southwestern Medical Center, showed that certain fats cause the brain to send messages to the body to ignore the normal mechanisms involved in weight regulation. Those mechanisms are hormones, such as leptin and insulin, that normally work by telling us we’re full and should stop eating, said Dr. Deborah Clegg, the lead author of the study. One type of saturated fat, palmitic acid, is particularly effective at blunting the normal hormone response. Palmitic acid is found in butter, cheese, ice cream, milk and beef.

‘Normally, our body is primed to say when we’ve had enough,’ Clegg said in a news release. ‘But that doesn’t always happen when we’re eating something good. What we’ve shown in this study is that someone’s entire brain chemistry can change in a very short period of time. Our findings suggest that when you eat something high in fat, your brain gets ‘hit’ with the fatty acids, and you become resistant to insulin and leptin. Since you’re not being told by the brain to stop eating, you overeat.’

The researchers also found that this effect lasts for about three days. So one splurge of foods high in fatty acids can cause a lengthy eating binge.

Though the study was in animals, Clegg said that saturated fat ‘causes you to eat more.’

The study appears in the September issue of the Journal of Clinical Investigation.

-- Shari Roan