Whether 100% fruit juice consumption causes weight gain in children remains controversial.
To determine the association between 100% fruit juice consumption and change in BMI or BMI z score in children.
PubMed, Embase, CINAHL, and Cochrane databases.
Longitudinal studies examining the association of 100% fruit juice and change in BMI measures were included.
Two independent reviewers extracted data using a predesigned data collection form.
Of the 4657 articles screened, 8 prospective cohort studies (n = 34 470 individual children) met the inclusion criteria. Controlling for total energy intake, 1 daily 6- to 8-oz serving increment of 100% fruit juice was associated with a 0.003 (95% CI: 0.001 to 0.004) unit increase in BMI z score over 1 year in children of all ages (0% increase in BMI percentile). In children ages 1 to 6 years, 1 serving increment was associated with a 0.087 (95% confidence interval: 0.008 to 0.167) unit increase in BMI z score (4% increase in BMI percentile). 100% fruit juice consumption was not associated with BMI z score increase in children ages 7 to 18 years.
All observational studies; studies differed in exposure assessment and covariate adjustment.
Consumption of 100% fruit juice is associated with a small amount of weight gain in children ages 1 to 6 years that is not clinically significant, and is not associated with weight gain in children ages 7 to 18 years. More studies are needed in children ages 1 to 6 years.
Comments
RE: Adjustment for Total Energy Intake
Hi Michael, thank you for your comment.
Whether or not to adjust for total energy intake in studies of weight gain is controversial, for some of the reasons you outline. The current tools nutrition science has to measure total energy intake are limited (FFQs, food records), and Dr. Marian Neuhouser of the Univ of Washington and Fred Hutch and her team have shown that estimates of total energy intake based on FFQs are systematically biased depending on factors like age, sex, BMI, and diet quality.
So, we actually did our meta-analysis both ways: with and without adjustment for total energy intake (see figures 2 and 3 on pages 8 and 9). Adjustment for total energy intake didn't have a big impact. We think the difference between figures 2 and 3 mostly has to do with which studies reported their results with and without total energy intake (the study by Shefferly did not report energy adjusted results).
Bottom line is that energy adjustment is important for weight gain studies, but controversial. In our study it didn't end up changing the results much.
A separate issue that your comment speaks to is the debate about, "are all calories equal"? Here is a great review paper in JAMA by David Ludwig (PMID 24839118), who argues that all calories are not created equally, and that calories from simple sugars have adverse effects on the body above and beyond their calories.
The point of multivariable regression models that adjust for total energy intake is to examine the effects of a nutrition exposure, like 100% fruit juice, above and beyond the calories.
Finally, the data on liquid calories not being compensated for in the same way that solid calories are is actually a bit thin. Analyses have certainly shown this, but they have had limitations.