I noticed yesterday that a certain study [1] concerning artificial sweeteners had got some press. In the study, overweight and obese adults were randomized to one of three dietary interventions:
1. advice to replace more than 200 calories a day of calorific beverages (softs drinks/soda) with water
2. advice to replace more than 200 calories a day of calorific beverages (softs drinks/soda) with diet drinks
3. no advice regarding beverages
All three groups received monthly group support and were asked to report their weight weekly. The study went on for a total of 6 months.
The study found according to the dietary records extracted during interview with a researcher, those in group one reduced calorie intakes by an average of 500 calories a day, wile those in group 2 had reduced calorie consumption by about 700 calories a day by the six-month mark. There has been some evidence suggesting that artificial sweeteners can increase appetite. And it seems this study has been used to dispel this idea.
However, there’s a few problems with this study as I see it. Firstly, it involved measures that individuals in their normal daily lives drinking diet drinks are not usually exposed to (such as group support sessions and interviews with researchers).
I also noticed that the researchers had failed to report the calorie intakes of those in group 3 (the control) group. That seemed a bit odd to me. But what was odder was that the weights of the groups was not reported in this study or even referred to in the paper.
The trial had been registered here and you can see that its primary aim was to assess the interventions on weight. So I contacted one of the authors who passed me on to another author who told me that the results on weight had been published in another study last year [2].
And when I read that other study it became, I think, clear to me why in this latest study weight was not referred to and the control group was omitted.
In short, what the original study found was that those who were told to substitute soft drinks/soda for water or diet drinks lost no more weight than those who did not apply this intervention.
I’ve said before that there is no good evidence that artificial sweeteners promote weight loss. Yet, the way the latest study is reported strongly hints at weight loss potential, even though the original study found, in essence, swapping soda for diet drinks produced no better results than the control group. Here’s the conclusion of the original study:
Replacement of caloric beverages with noncaloric beverages as a weight-loss strategy resulted in average weight losses of 2% to 2.5%. This strategy could have public health significance and is a simple, straightforward message.
Notice no mention here at all of the fact that the intervention was no better than no intervention, which strongly points to the fact that it was not the intervention but other things (e.g. group sessions, weekly weight reporting) that had any beneficial effect.
The original registration of the trial tells us that a sponsor or collaborator of the study is Nestle Waters North America, Inc. But in both of the studies we are assured that this company had nothing to do with the design and conduct of the study nor its preparation or review. You can decide for yourself whether there’s any likelihood that industry involvement perverted the objectivity and honesty of these researchers.
References:
1. Piernas C, et al. Does diet-beverage intake affect dietary consumption patterns? Results from the Choose Healthy Options Consciously Everyday (CHOICE) randomized clinical trial. Am J Clin Nutr. 2013 Jan 30. [Epub ahead of print]
2. Tate DF, et al. Replacing caloric beverages with water or diet beverages for weight loss in adults: main results of the Choose Healthy Options Consciously Everyday (CHOICE) randomized clinical trial. Am J Clin Nutr 2012;95:555–63
