Ask the Doctors by Eve Glazier, M.D. and Elizabeth Ko, M.D

Increased Diet Soda Intake Linked to Host of Health Problems

Dear Doctor: I feel better when I eat less sugar. Because I love having a soda with my snacks and meals, I drink a few diet colas every day. Is it true that diet sodas can increase the risk of developing diabetes?

Dear Reader: Kudos to you for working to cut sugar out of your diet. It's a lifestyle choice that helps to stabilize blood sugar levels, makes it easier to maintain a healthy weight, lowers risk of diabetes and does your dentist a big favor.

However, and we're sorry to be the bearers of unpleasant news, the diet sodas you rely on to shrink your sugar intake are not a zero-sum tradeoff. Recent studies show a link between the regular consumption of diet soda and a whole host of unpleasant consequences. And, yes, increased risk of certain types of diabetes is among them.

How and why artificial sweeteners may have the same metabolic effects as the sugar they replace is not yet fully understood. The research in question relies on participants' own recall of their eating habits, as well as on aggregated data. That's not to say these types of observational studies aren't useful or accurate. It just means that additional factors beyond the researchers' control may have played a role in the studies' results.

Still, the research is compelling. In a recent Swedish study that analyzed the health outcomes of 2,800 adults, it was found that participants who drank slightly less than 1 cup of soda per day more than doubled their risk of developing Type 2 diabetes. Up that intake to a liter of soda per day, and the likelihood of developing the disease grew tenfold.

The surprise was that it didn't matter whether participants were drinking sugared sodas or ones that were artificially sweetened. Their increased risk of diabetes was the same. This echoed the results of several other studies, including one in 2009 sponsored by National Heart, Lung, and Blood Institute, and one published in the American Journal of Clinical Nutrition in 2013. Additional studies have found evidence that certain artificial sweeteners contribute to glucose intolerance and weight gain.

Why would this be?

One school of thought is that while artificial sweeteners trick the taste buds, they don't fool the satiety centers in the brain. As a result, rather than slaking the craving for something sweet, they actually stimulate appetite and cravings. Another line of inquiry is whether artificial sweeteners may adversely affect the beneficial microbes in the gut and thus cause glucose intolerance.

If any of this leads you to consider changes in your soda intake, we have a few thoughts. First, don't switch to fruit juice, which is also heavy in sugar. Instead, think fizzy water. We have found that patients who say they are addicted to diet sodas love not just the sweetness, but also the physical sensation of the carbonated bubbles.

Try switching to sparkling water. You can spike it with a squeeze of citrus, a few slices of cucumber or even crushed herbs. Various brands have different tastes and even different-sized bubbles. Shop around, find a few brands that you like and, to increase your chance of success, make the switch gradually.

(Send your questions to, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)