Science

Michelle Nguyen, HBSc; Sarah E. Jarvis, MSc; Laura Chiavaroli, PhD

Importance
Concerns have been raised that frequent consumption of 100% fruit juice may promote weight gain. Current evidence on fruit juice and weight gain has yielded mixed findings from both observational studies and clinical trials.

Objective
To synthesize the available evidence on 100% fruit juice consumption and body weight in children and adults.

Data Sources
MEDLINE, Embase, and Cochrane databases were searched through May 18, 2023.

Study Selection
Prospective cohort studies of at least 6 months and randomized clinical trials (RCTs) of at least 2 weeks assessing the association of 100% fruit juice with body weight change in children and adults were included. In the trials, fruit juices were compared with noncaloric controls.

Data Extraction and Synthesis
Data were pooled using random-effects models and presented as β coefficients with 95% CIs for cohort studies and mean differences (MDs) with 95% CIs for RCTs.

Main Outcomes and Measures
Change in body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) was assessed in children and change in body weight in adults.

Results
A total of 42 eligible studies were included in this analysis, including 17 among children (17 cohorts; 0 RCTs; 45 851 children; median [IQR] age, 8 [1-15] years) and 25 among adults (6 cohorts; 19 RCTs; 268 095 adults; median [IQR] age among cohort studies, 48 [41-61] years; median [IQR] age among RCTs, 42 [25-59]). Among cohort studies in children, each additional serving per day of 100% fruit juice was associated with a 0.03 (95% CI, 0.01-0.05) higher BMI change. Among cohort studies in adults, studies that did not adjust for energy showed greater body weight gain (0.21 kg; 95% CI, 0.15-0.27 kg) than studies that did adjust for energy intake (−0.08 kg; 95% CI, −0.11 to −0.05 kg; P for meta-regression