Can Diet Pop Interfere With Weight Loss?

sharma-obesity-tap-water1According to conventional wisdom, beverages with artificial sweeteners should be weight neutral, given that they do not contain calories. However, whether this is true or not remains controversial. Besides the epidemiological evidence suggesting that the consumption of artificially sweetened beverages may be associated with higher body weights, there are also a range of physiological studies suggesting that artificial sweeteners can induce metabolic changes (including changes in taste preferences) that may promote weight gain.

Now, a study by Ameneh Madjd and colleagues from the University of Nottingham, UK, and the Tehran University of Medical Sciences, Iran (where the study was conducted) published in the American Journal of Clinical Nutrition, suggests that replacing ‘diet beverages’ (DBs) with water may not only result in greater weight loss but may also have greater benefits in terms of glucose metabolism.

The study was conduced in 89 women with overweight or obesity who usually consumed DBs in their diet.

Participants were randomized to either replace their DBs with water or continue drinking DBs 5 times/wk after their lunch for 24 wk (DB group) while on a 24-week weight-loss program.

71% of participants completed the trial (32 in the DB group, 30 in the water group).

Over the 24 weeks, the water group lost about 1.2 Kg more than the DB group (mean weight loss of both groups was about 8 Kg).

Improvements in fasting insulin levels, HOMA index and 2-hr post-prandial glucose also tended to be greater in the water than in the DB group.

Thus, the authors conclude that replacement of DBs with water after the main meal may lead to greater weight reduction and more favourable metabolic benefits during a weight-loss program.

As for the possible mechanisms that would account for these findings, the authors speculate based largely on self-reported changes in food intake that the water-drinking group may have been more compliant to the recommended diet and may have marginally reduced their carb intake.  There is also the possibility that drinking water (rather than DBs) may support weight loss through other mechanisms.

Overall, I am not sure what to really make of this study. Clearly, being able to replace DBs with water may be beneficial. On the other hand, the more common problem in my practice is dealing with patients who consume larger amounts of sugar-sweetened beverages (SSBs rather than DBs) and I would imagine that if a shift to water is too drastic, DBs may at least be substantially better than continuing on with SSBs for these patients.

Edmonton, AB