Does Diet Soda Make You Fat?

Last weekend, a girlfriend that I’ve known since college was visiting. As we left the airport, we had to stop at the grocery for a case of diet soda. My friend drinks five or so cans a day. On our way to lunch now happy with her diet soda in hand my friend asked me “Do you think that drinking diet soda makes you fat?”

“Depends on whom you ask,” I said. Last year, researchers from the University of Texas Health Science Center in San Antonio reported that adults who drink diet soda (we’re talking only one can or bottle a day) did not lose weight. They were actually more likely to become overweight than those adults who did not drink soda at all OR those that drink regular soda. In fact, the more diet soda consumed, the more likely someone would become overweight. To be specific, there was a 41% increase in the risk of being overweight for every can or bottle of diet soda consumed daily.

In this study, researcher Sharon Fowler followed over 600 normal weight adults ages 25-64 over a seven to eight year period of time. She has a number of theories as to why weight gain may be a result of drinking a zero-calorie beverage:

1. Artificial sweeteners may affect your body’s ability to judge how many calories you consume because you are getting something sweet without any calories. When no calories are consumed, the body may continue to crave what it expected and could lead to overeating or bingeing.

2. Some people give up regular sodas to justify their favorite dessert and still take in too many calories. A regular soda contains about 9-12 teaspoons of sugar (yes, you read that correctly) and about 150 calories while your dessert may be double that in calories easily.

3. For others who were gaining weight already, switching to diet soda wasn’t enough to stop the gain. You’ve heard this one before…you’re being good and order a diet soda along with your fast food burger and French fries but the calories are still quite high.

Since her first piece of research, Fowler has tracked another 2000 people with similar results. Do the faux sweet products induce people to want more sweets? Fowler suggests that perhaps it’s not the soft drinks themselves that cause weight gain but that there is some link between diet soda drinking and overweight/obesity.

I’ll be watching the research for more news on this debated topic. In the mean time, do any of you feel that drinking diet sodas makes you crave more sweets? What about using sugar substitutes? Just curious.

Dr. Susan