PhotoLosing weight can be difficult for a number of different reasons. If you’re just starting out, it can be difficult to make certain necessary life changes, such as getting more sleep, exercising more, or eating smaller amounts.

Eating less, in particular, may be one of the more challenging adjustments to make because of how easy it might be to comfortably overeat. In fact, one new study has shown that eating too much in one sitting actually makes it easier to keep eating after a certain point.

Researchers have found that when the stomach senses too many calories, a certain hormone that makes you feel full is suppressed, enabling you to eat even more.

Cycle of overeating

The study, which was conducted by researchers at Thomas Jefferson University, actually began due to findings in earlier studies focusing on colon cancer. Researchers observed that uroguanylin, a hormone that sends signals to the brain to convey fullness, was present in non-obese mice, but it disappeared in models that were obese.

To investigate, researchers analyzed mice who were overfed and found that their small intestines stopped producing the hormone after a high number of calories were consumed. The receptors that were meant to receive those signals were still intact, they just weren’t getting any.

The researchers hypothesized that overeating was the cause of the disruption and set out to see if they could manipulate uroguanylin production. They found that when the mice were put on a diet, production of the hormone resumed.

“What’s interesting is that it didn’t matter whether the mice were lean and overfed, or obese and overfed – uroguanylin production stopped in both groups of animals when they got too many calories,” said Dr. Scott Waldman, one of the leaders of the study. “Here, it’s not the obese state that’s causing the problem but rather it’s the calories.”

Possible causes

While the researchers are not yet completely certain what causes uroguanylin to stop being produced, they strongly suspect that it has to do with the endoplasmic reticulum (ER) of cells in the small intestine. The ER produces many of the body’s proteins and hormones, but its function can be disrupted when it is stressed.

As a test, the researchers applied a chemical to the ER to stress it – a replication of what would happen if the mice were overfed. They observed that when the ER was stressed, it stopped producing uroguanylin. When another chemical was applied to de-stress the ER, production of the hormone went back to normal.

Implications for obesity

The researchers believe that this series of experiments show that high calorie consumption can stress the small intestines and cause people to stop feeling full after eating too much. However, what they don’t know is how important uroguanylin is in the grand scheme of obesity.

“Like in cancer, there are many steps on the way to becoming obese that aren’t easily reversed. While the uroguanylin hormone pathway appears to be one of those steps, we don’t yet know whether it’s important early on in the process, or later, and how much of a role it plays. But in combination with other approaches, hormone replacement of uroguanylin may become an important component of therapy to reverse obesity,” said Waldman.

The full study has been published in the journal Nutrition and Diabetes.

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