Diet soda doesn't make you fat -- it's the extra food

“I suspect that people are likely drinking those diet sodas to wash down high-fat and high-calorie fast-food or take-out meals, not as a complement to a healthy meal prepared at home or to quench a thirst after a tough workout,” said Jessica Bartfield, MD, who specializes in weight and nutrition at Gottlieb Memorial Hospital.

Dr. Bartfield takes issue with two recent studies that were presented at the American Diabetes Association in June that conclude that diet soda negatively affects your waistline.

One study tracked 474 people, all 65 to 74 years old, for nearly a decade. It measured height, weight, waist circumference and diet soda intake every 3.5 years. The waists of those who drank soft drinks grew 70 percent more than those who did not.

Another study found that after three months of eating food containing aspartame, mice had higher blood sugar levels than rodents that ate regular food. Researchers concluded that aspartame could trigger the appetite but not satisfy it, leading you to eat more in general.

“The association studies are significant and provocative, but don’t prove cause and effect,” said Bartfield, who counsels weight-loss patients at the Chicago-area Loyola University Health System. “Although these studies controlled for many factors, such as age, physical activity, calories consumed and smoking, there are still a tremendous number of factors such as dietary patterns, sleep, genetics, and medication use that account for weight gain.”

For people trying to lose weight, switching from sugar-sweetened beverages to diet soda can have a tremendous impact on calorie reduction, but Dr. Bartfield feels it still boils down to one basic principle.

“It still comes down to moderation,” she said. “I caution patients to keep it to one or two diet sodas per day.”

Provided by Loyola University Health System