Diet drinks probably have a role in weight control

The New England Journal of Medicine published three articles on diet soft drinks (timing coincided with data being presented at The Obesity Society medical meeting).

Not surprisingly, the general conclusion is that, yes, sugary drinks make you fat (well – more accurately they seem responsible for a few of those extra pounds).

The strongest evidence was in an article looking at people with genes known to predispose to obesity. Over a period of between 6-18 years, those who drank sugary drinks were about 4-6 pounds heavier than non-drinkers.

Two other studies were in kids. The first article followed kids from about age 5 to age 12 for a period of 18 months. Kids who already drank sugary drinks on a daily basis were randomized to continue or to switch to Splenda-sweetened drinks (Splenda is generically known as sucralose). This study was done in the Netherlands, by the way. (To check compliance, the researchers periodically tested urine samples. The Splenda cohort consistently had Splenda in their urine while the regular-drink group had no urinary Splenda.  Pretty clever). The results were that after 18 months, the diet-drink group weighed about 1 kg (2.2 pounds) less than the sugar-drink group.

One additional finding of note in this study – the kids had no idea whether they were drinking diet or regular drinks. 50% outright admitted they had no idea. Of the ones that said they thought they knew, only 40% guessed correctly they were on diet drinks (worse guessing than would be expected purely from chance). What does this mean to me? Kids just want to consume sweets. The nature of the sweetener (sugar vs. artificial) is irrelevant.

The final study (done at Boston Children’s Hospital) evaluated adolescents who already drank sugary drinks. Half the study participants were counseled on switching to diet drinks. One year later, the sugary-drink-group was 1.8 kg (about 4 pounds) heavier.  At two years, however, the sugar drink group was only 0.8 kg (about 2 pounds) heavier. The difference at two years was not statistically significant.

In aggregate, these data points tell me that sugary drinks matter. There are a lot of ways to get calories, and cutting down on sugary drinks is one small piece of the picture in terms of avoiding obesity.

Of note, an article in the journal “Pediatrics” estimated that 10-15% of caloric intake in children is from sugary drinks (including fruit juice). That’s striking. There’s no need for that, especially with obesity on the rise. Sugary drinks matter. Diet drinks are completely safe (see here) and therefore should be the default choice over their sugary-laden counterparts.


  1. New England Journal of Medicine – Sugar-Sweetened Beverages and Genetic Risk of Obesity
  2. NEJM – A Trial of Sugar-free or Sugar-Sweetened Beverages and Body Weight in Children
  3. NEJM – A Randomized Trial of Sugar-Sweetened Beverages and Adolescent Body Weight
  4. Pediatrics – Increasing Caloric Contribution From Sugar-Sweetened Beverages and 100% Fruit Juices Among US Children and Adolescents, 1988–2004
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1 comment for “Diet drinks probably have a role in weight control

  1. Marisa
    September 23, 2012 at 1:46 pm

    Perhaps “water” should be the default drink choice?

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