Diet soda may be linked to an increased risk of diabetes, but not as much as bad eating habits. According to a new study, diet soda drinkers have a higher risk of metabolic syndrome, a combination of disorders that can lead to heart disease and type 2 diabetes. But the difference is minor when compared to the food these people choose to eat.
Watch the news video below discussing the health effects of both diet and regular soda:
The research, published in the April issue of the American Journal of Clinical Nutrition, examines the diets and soft-drink habits of over 4,000 young adults who took part in the Coronary Artery Risk Development in Young Adults (CARDIA) study, over a 20-year period.
Overall, those who drank diet sodas actually had a higher risk of metabolic syndrome than non-diet soda drinkers. But when you factor in everything else the participants were eating, the results were not so cut and dry.
The group that was at the lowest risk for metabolic disorders were those who had "prudent" eating habits, consisting of things like fruit, fish, whole grains, nuts and milk, and who did not consume diet sodas. Next on the hierarchy were those with the "prudent" diet, who also drank diet soda.
Those with the highest risk ate what the researchers term "western" fare, including fast food, meat, pizza and snacks, but instead of regular pop, they would opt for diet alternatives.
"There was an important interplay between overall diet and what people drink," says Kiyah Duffey, study author and research assistant professor of nutrition at the University of North Carolina's Gillings School of Global Public Health. "It is important that people consider the entirety of their diet before they consider switching to or adding diet beverages, because without doing so they may not realize the health benefits they were hoping to see."
The study surprised Sharon Zeiler, dietitian and senior manager of diabetes education and nutrition at the Canadian Diabetes Association. But she thinks one of the reasons for the unexpected results could be that people drinking diet sodas might be filling up on calories elsewhere. And an excess of calories could contribute to metabolic syndrome because one of the risk factors for the syndrome involves extra weight around the middle and upper parts of the body.
"Other studies have shown that people who drink diet soda have the idea that they've done something virtuous," she explains, "and that they can replace the calories they didn't have with the diet soda by eating more of other things."
The diet soda debate is a confusing one, full of conflicting research and confusion. One recent study has pointed to the nefarious effects of diet drinks on consumer waistlines. But on the other hand, a large-scale study published in the New England Journal of Medicine last year found that diet soda consumption led to no increase in weight.
But Zeiler sees a need for low-calorie options like diet soda. "Our recommendation is that water is the best thing," she says. "But there should be consumer choice. A lot of people really like to have pop, and they like the idea of having it. A meal wouldn't be complete without their can of coke."
In those cases, she believes diet soda is still the lesser of two evils.