The Food Journal and Food, Nutrition & Science

An alliance between The Lempert Report and The Center for Food Integrity

Diet Drinks and Weight Loss

Diet Drinks and Weight Loss

Health and Wellness

March 25, 2012

Replacing caloric, sugar-sweetened beverages with diet beverages could be part of an effective weight-loss strategy, according to a recent study from The University of North Carolina at Chapel Hill. Researchers found that swapping out caloric beverages for noncaloric ones resulted in average weight losses of 2 to 2.5%.


Researchers had hypothesized that substituting a non-caloric beverage, whether it was water or diet beverages, would lead to significant weight loss. This study was unique in that it was one of the first randomized controlled trials to explore the issue of beverage substitution and weight loss. To prove their theory, researchers compared the replacement of caloric beverages with water or diet beverages as a method of weight loss with a control group over a six month period in adults.

People who switched to calorie-free beverages were twice as likely to lose five percent or more of their body weight than those who were not counseled to change beverages. People in the water arm had lower fasting glucose levels and better hydration levels than the control group.

Interestingly, it was slightly easier for the diet beverage group to reduce calories in the short-term, at three months – as compared to the water group. People may do better slowly weaning themselves off caffeine as they transition to water, says Dr. Brie Turner-McGrievy, one of the study’s authors and Assistant Professor in the Department of Health Promotion, Education and Behavior at the University of South Carolina. Dr. Turner-McGrievy and colleagues are exploring how sweet preference plays a similar role in adhering to the beverage substitution recommendations over time.

“Some people may drink caloric beverages, like soda and sweet tea, because they enjoy sweet foods or have a strong preference for sweet foods and drinks. The diet drinks, which still taste sweet, may have appealed to this group of sweet likers as an easier way to discontinue their caloric beverage intake,” says Dr. Turner-McGrievy.

For their part, the control group reduced caloric beverage intake somewhat but not as much as the other two beverage groups, who were specifically counseled to substitute their caloric beverages with a non-caloric alternative. The control group was an active comparison group, which received general information on weight loss so they made choices on how they would decrease their caloric intake (and some did through reducing their beverage intake). Meanwhile, the water group experienced some benefits in greater numbers than the diet beverage group – like improved fasting glucose and urine osmolality (a measure of hydration).

There are many benefits of recommending small but potentially sustainable lifestyle changes for improving health and diet, says Turner-McGrievy. She points out that some people may balk at making large changes in their diet, for one. Furthermore, monitoring caloric intake so you know how much you are eating can be burdensome when you are trying to reduce caloric intake. Making small substitutions can be easy to do, Turner-McGrievy says, and these changes don’t take more time or cost more money.

Over 20% of our calories are now coming from sugar-sweetened beverages. Health professionals can use this as a starting point to get their patients to make healthy changes in one aspect of their diet that is contributing an excess of empty calories. Health professionals could provide a plan to their patients on how to substitute healthier, non-caloric beverages, like water, for sugar-sweetened beverages. 

“Assessing barriers to water consumption (like taste, need for caffeine, enjoyment of carbonated beverages) can allow health professionals to provide tailored recommendations. Examples could be adding fruit slices to water for added flavor or trying seltzer water to get the carbonated beverage mouth feel,” adds Turner-McGrievy.