Health Advice



Zero weight loss from zero calorie drinks? Say it ain’t so

Robert H. Shmerling, Harvard Health Blog on

Published in Health & Fitness

Are you trying to cut back on calories by making the switch from regular soda to diet soda? Do you prefer carbonated water with a bit of flavor, such as Hint or LaCroix? Or maybe you’ve purchased a carbonating device like SodaStream or Drinkmate?

Research suggests that none of these choices may actually help with weight loss. Worse, they might even lead to weight gain! The reason might surprise you. It sure surprised me.

The problem with regular sodas isn’t just the calories

If you’re drinking two 12-ounce cans of regular Coke each day, you could eliminate 280 “empty” (non-nutritive) calories by switching to a zero-calorie alternative. Over a month, that’s 8,400 fewer calories, enough to lose almost two and a half pounds. So, what’s the catch?

One worry is that artificially sweetened diet sodas may create a craving for sweet, high-calorie foods. So, even as calorie counts drops from zero-calorie sodas, consumption of other foods and drinks might add back even more. In rodent studies, at least one artificial sweetener (aspartame) has been found to damage a part of the brain that tells the animal when to stop eating.

And a number of studies in humans (such as this one and this one) have actually found a tendency toward weight gain among people drinking artificially sweetened beverages. But research has been mixed: other studies have found that artificially sweetened low-calorie beverages can help with weight loss.


One factor complicating the study of zero-calorie beverages and weight loss is called “reverse causation.” People at risk for obesity tend to choose these beverages, making it appear that these drinks are to blame.

Of course, there are other health concerns associated with artificial sweeteners, including a possible increase in the risk of certain cancers, cardiovascular disease, and kidney problems. The evidence for this isn’t strong enough to be sure, though.

Surely carbonated water with no artificial sweeteners is fine?

Drinks that contain carbonated water and no artificial sweeteners have long been considered safe bets when it comes to breaking the regular soda habit. With none of the sugar, calories, or artificial sweeteners, how can you go wrong?


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