Carbonated Beverages and Weight Gain - What’s the link? We know that sugar-sweetened and even artificially sweetened beverages are linked to weight gain. How about just plain carbonated drinks? 

When you drink a carbonated beverage, the carbon dioxide can stretch the stomach and release a hormone called ghrelin. Ghrelin is a hormone that acts as a neurotransmitter in the brain to create the sensation of hunger. This results in increase food consumption and weight gain. Let's look at the evidence both in animal models and humans.