That ice-cold soda that sounds so good on a blazing afternoon might do more than quench your thirst, Georgia researchers say. It may be one of the key things makes people gain weight.
“Even more so than sugar-laden foods, scientists have evidence that sugary drinks can quickly make rats – and likely us – resistant to the satiety hormone leptin,” said researchers from the Medical College of Georgia at Augusta University in a news release.
The hormone is supposed to make you feel full when you’ve eaten enough food. But when researchers offered rats sugary water to drink, they just kept eating and drinking, and they kept gaining weight. Researchers believe this same thing may be happening to humans.
“We think this adds to the evidence that it would be a good thing not to drink a lot of sugar,” said Dr. Ruth B.S. Harris, physiologist in the Department of Physiology at the Medical College of Georgia at Augusta University.
About a third of adults and 17 percent of children are obese in the United States and sugary beverages are clearly involved, Harris said.
The problem is compounded by the fact that the sugar is delivered to the body much more quickly with drinks than with food.
“When you drink a sweetened drink you’re getting just the sucrose,” she said. “Whereas if you eat foods that are sweet, you are getting the sucrose that is mixed in with other things like protein and fiber.”
Harris recently received a $1.6 million grant from the National Institutes of Health to learn more about the mechanism behind how this process happens.
Here’s how Harris says it works:
When you eat sugar, it is converted into either glucose or fructose, which the body needs for energy. When the body starts using it, some helps control whether certain proteins are turned on or off. Those, in turn, can help control whether or not leptin is activated.
When you eat more and more sugar, that pathway is bombarded with so many carbohydrates that a key protein, called STAT3, stops working correctly, and that causes leptin to stop working properly too.
When Harris gave the rats water, food and sugar water, they seemed to gravitate towards the sugar water more than anything else, and they began gaining weight. In fact, they drank more and more sugar water, ate less food, and drank almost no plain water at all, Harris said. By day 25, female rats didn’t respond to leptin at all. By day 31, neither did any of the males.
“If you don’t respond to leptin, the leptin is not going to suppress food intake,” Harris said. “That means you are at risk for overeating and gaining more weight.”
The good news? After only two days without drinking sugar water, rats began responding to leptin again, and stopped gaining weight.
Scott Berson: 706-571-8578, @ScottBersonLE