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Why Weight Loss is Hard: It's Your Brain

Kathleen Blanchard's picture
New finding shows our brain makes us want to overeat.

Putting on extra pounds is easy. So why is it so hard to lose weight then? Researchers have discovered something occurs in our brain when we become overweight or obese that makes the body want to overeat.

Brain cells shift with obesity

A team of American and Italian neuroscientists found what happens in the hypothalamus of the brain's neurons that makes us so hungry.

Ken Mackie, professor in the Department of Psychological and Brain Sciences in the College of Arts and Sciences at Indiana University of Bloomington explains when we put on weight a switch occurs in the brain signaling cells of the hypothalamus.

The result is release of a chemical peptide that makes use hungry known as orexin. Rather than the brain telling us to maintain weight that is healthy, it tells us to eat more.

The finding, published in the Proceedings of the National Academy of Sciences, identifies a molecular switch that happens in the brain.

"The striking finding is that you have a massive shift of receptors from one set of nerve endings impinging on these neurons to another set," said Ken Mackie, professor in the Department of Psychological and Brain Sciences in the College of Arts and Sciences at Indiana University Bloomington in a press release.

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Orexin is normally inhibited by the ends of brain receptors, but once it is activated the peptide is promoted by the brain cells.” Mackie said the finding means the potential for new obesity treatments.

Mackie said appetite is controlled by several neurochemical systems, one of which is the endocannabinoid system that contains receptors and chemicals similar to marijuana.

Mackie said one theory is that the system resets itself with obesity. We eat to control our current state of being overweight because the brain tells us to.

The study

The scientists studied obese mice to find the brain connection to overeating and obesity. They found the ends of CB1 cannabinoid nerve receptors become enriched in the area that normally inhibits release of orexin; then the body produces more endocannabinoids to make us hungry.

Mackie said the study shows why the body wants to return to a heavier weight. They also found that the so-called hunger hormone leptin becomes higher with obesity. When the hormone levels are high for long periods of time, brain cells become less sensitive to its action, also contributing to more orexin release.

What the finding could mean for you

  1. If you are finding it difficult to stop overeating from hunger, choose foods that are satisfying. Example include vegetables, air popped popcorn that has fiber to produce satiety and staying well-hydrated with water.
  2. Consider joining a support group for overeaters. Find a buddy who is also trying to diet.
  3. Engage in self-talk. Set a goal and tell yourself why it is important to cut back on food consumption. If you have a lapse, just resume cutting back on food intake the next day.
  4. Try to lose weight early. If you put on 5 to 7 pounds, cut back on calories sooner than later and increase exercise. Waiting too long to diet could be much more difficult for weight loss because of the brain shift that happens with obesity; identified in the research.
  5. Don't eat snacks or meals late. Eating earlier in the day can help you beat late-night cravings.

    IU Newsroom
    April 29, 2013