Can Zero-Calorie Drinks Lead To Weight Gain?

It looks like so-called “diet” drinks, which promise zero-calories and zero regret, can actually cause you to overeat, gain weight and put you at risk of obesity. In a new study, scientists found that certain areas of the brain react differently between calorie-free sweeteners in diet drinks, like saccharin, and sugar.

Researchers Erin Green and Claire Murphy from University of California, San Diego and San Diego State University conducted a study of 24 healthy young adults. They were subjected to a series of brain imaging tests while given small doses of saccharin and sugar-sweetened water. Half of them reported having zero-calorie drinks at least once a day, while the rest seldom consumed these drinks.

For the diet soda drinkers, as their consumption of diet soda climbed, the brain became confused and could no longer tell the difference between calorie-free sweetener and regular sugar. Due to this, the activation of a region in the brain associated with the food motivation and reward system is then diminished, and the caloric intake and subsequent energy consumption cannot be calculated. So the brain is tricked and the person thinks that they need to consume more food.

Green and Murphy also reported in the latest issue of Physiology & Behavior that the decreased activation of this brain region is linked with elevated risk of obesity.

“The brain normally uses a learned relationship between sweet taste and the delivery of calories to help it regulate food intake,” says researcher Susan Swithers of Purdue University, who found similar results when she tested saccharin and sugar in animals two years ago. “But when a sweet food unreliably delivers bonus calories, the brain suddenly has no idea what to expect.”

So, if you really want a sweet drink, you may want to go for one with real sugar. The brain will be able to account for the calories and allow you to feel satisfied and won't make you think that you need any extra food. Just make sure not to overdo your consumption of sugar...as they say, moderation is key.