Reducing intake of sugary drinks has effect on BMI while intervention is maintained

Image: PD

Key Study Points:

1)      With a 1-year intervention geared at reducing the intake of sugary beverages, the consumption of sugary beverages was curtailed and BMI was significantly decreased in comparison to a control group at the end of the year.

2)      There was no difference between the intervention group and the control group with respect to BMI one year after the intervention was stopped (i.e. at 2 years).

Primer: Adolescent obesity is a serious public health concern in the United States, and it has been rising at dramatic rates in recent times. Given the rise of obesity and recent exposure in the media of measures such as the banning of large sizes of soft drinks, the issue of the effect of sugary drinks on weight gain has recently gained much attention. Sugary beverages make for low quality calories and poor satiety, and the cardiovascular and metabolic dangers of adolescent obesity are well documented. Past studies have shown that consumption of sugary beverages can be reduced with multimodality intervention and that such curtailment may possibly help in lowering BMI. This study aimed to investigate the effect of sugary drinks on weight gain and BMI in overweight children.

Background Reading:

1. Effects of Decreasing Sugar-Sweetened Beverage Consumption on Body Weight in Adolescents: A Randomized, Controlled Pilot Study [Pediatrics]
2. Sugar-Sweetened Beverages, Weight Gain, and Incidence of Type 2 Diabetes in Young and Middle-Aged Women [JAMA]
3. Intake of sugar-sweetened beverages and weight gain: a systematic review [Am J Clin Nutr]
4. Liquid calories, sugar, and body weight [Am J Clin Nutr]

This [randomized] study:  224 adolescents in grade 9 or 10 that reported consuming at least one 12-ounce serving of a sugary beverage and were at or above the 85 percentile for weight relative their gender and age were enrolled into the study. Participants were randomly assigned to the treatment or control group: (1) the treatment group became participants in a multi-modality intervention program that aimed to reduce their daily intake of sugar-sweetened beverages and 100% fruit juice; (2) the control group participants were given a $50 supermarket voucher monthly, without restriction on purchases. The intervention was administered for a 1 year span though BMI and body fat were measured after 1 year and 2 years.

The participants in the experimental group had a significant decrease in BMI at the end of the first year (p=0.045), though there was no significant difference between the groups at 2 years. The participants in the treatment group did have a significant change in consumption of sugary beverages compared to the placebo group at 1 and 2 years (p<0.001, p=0.005 respectively).

In Sum: This study showed a decreased intake of sugar-sweetened beverages and 100% juice with a decrease in BMI at the end of one year of intervention. It must be noted that the BMI effect did not persist at 2 years (one year after discontinuing the intervention). This may infer that multimodality intervention may be effective in decreasing BMI as long as the intervention is continued.  Although the only target of intervention was against sugary drinks, there was a trend of the participants in the treatment group to spend less time watching TV; while it is impossible to interpret causation, the correlation is noteworthy. Also of note, participants in the treatment group continued to have a significantly decreased intake of sugary beverages at the end of the second year without the intervention which would suggest that there is some persistence of the modifications from the intervention despite the negative result of the primary outcome (i.e. no change in BMI at 2 years).

In the end, this study is significant in showing that with sufficient intervention, dietary behavior can be altered with the hope of ultimately leading to healthier body mass indices and healthier lives in general. The best strategies to promote and maintain healthy changes remain an absolutely critical topic of future research and debate in the setting of dramatically rising rates of adolescent obesity.

Click to read the study in NEJM

Click to read a related study among normal body weight children in NEJM

By [RS] and [RR]

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