Diet soda: A key to weight loss?
Writing in the International Journal of Obesity, the researchers, two of whom have affiliations with the low energy sweetener industry, say low energy sweetener (or LES) diet drinks are surrounded by conflicting perceptions on the effect on weight loss.
The study looked at evidence surrounding the use of low energy sweeteners (LES) - such as stevia, sucralose and aspartame - and their effect on weight control.
“We found a considerable weight of evidence in favor of consumption of LES in place of sugar as helpful in reducing relative EI [energy intake] and BW [body weight], with no evidence from the many acute and sustained intervention studies in humans that LES increase EI,” the study said.
“Importantly, the effects of LES-sweetened beverages on BW also appear neutral relative to water, or even beneficial in some contexts.”
Consumer perceptions
Peter Rogers, professor of biological psychology with a focus on Nutrition and Behavior at the University of Bristol, told BeverageDaily the researchers wanted to address the confusion between LES and sweeteners with sugar. He said there were perceptions that LES could lead to a desire for sweet tasting products and relax a user’s restraint in eating.
Rogers and his team wanted to look at data that was available to see which points were true and which were not.
“Really the evidence was pretty clear,” he said. “The strongest sources of evidence, the human studies we looked at, they say consistently that consuming LES reduces energy intake and long term reduces body weight as well … I’m really confident about the conclusions that we came to.”
Why are LES diet drinks facing negative reactions from some consumers? Rogers said many stories about LES sound plausible - so people accept them as facts.
“One thing we’ll often hear from people is ‘Oh, they fool the boy into thinking there are calories in the food because blood pressure drops or you think you’re hungry.’ I guess because it sounds plausible, people believe it,” he said.
Better than water?
Rogers said that LES aren’t increasing energy intake or bodyweight, so in many cases, they can be at least as good as water for weight loss.
“Low calorie sweeteners might have some advantage over water in certain contexts,” he said.
“If I’m consuming sugar-containing sodas and I want to cut the sugar out, then it’s easier for me to change to diet sodas than to water. I think that’s one way in which the diet sodas might have an advantage over water.”
Another possible advantage LES drinks may have is to help reduce the desire for sweet drinks and desserts.
While this theory still needs to be tested, he said LES do not increase appetite or a desire to eat sweet treats, as others have suggested.
However, he does believe water and drinks featuring LES are at least equivalent in the help they can lend to weight loss.
How much benefit LES drinks have depends on the amount of sugar someone consumes in the first place, Rogers said.
“Really it’s about how much energy you can take out of your diet,” he said. “That depends on your current baseline of sugar intake.”
“What our review suggests, roughly, is that if I had to drink a 200 calorie can of soda, my appetite will be reduced by about 100 calories. If I wasn’t to drink that soda or take it with a diet soda, I save about 50 calories.
"If I was drinking three sodas a day, each 200 calories, I might save up to about 300 calories. That, of course is actually quite a lot, especially accumulated over time. That would have a big effect.”
As listed in the “conflict of interest” section of this study, two researchers on this study were employees and shareholders of companies that manufacture products containing LES.
Source: International Journal of Obesity
doi: 10.1038/ijo.2015.177
Does low-energy sweetener consumption affect energy intake and body weight? A systematic review, including meta-analyses, of the evidence from human and animal studies
Authors: P. Rogers, P. Hogenkamp, C. Graaf, S. Higgs, A. Lluch, A. Ness, C. Penfold, R. Perry, P. Putz, M. Yeomans and D. Mela
