Preventing weight gain with calorie-labeling.
OBJECTIVE
Calorie-labeling has been suggested as an anti-obesity measure but there is no evidence for its effect, to date. Early adulthood is a critical life-cycle period for unwanted weight gain and obesity development. This study examined whether providing calorie information would help young adults to avoid weight gain.


METHODS
Using a pragmatic interrupted time-series study design, weight changes over 36 weeks were reported among two year-groups, each of 120 young adults, similar in age, gender, and ethnicity, living in fully-catered accommodation. Year 1: subjects were observed without calorie-labeling, apart from a 5-week pilot. Year 2: calorie-labeling was present prominently and consistently at main meals for 30 of the 36 weeks.


RESULTS
Mean weight changes over 36 weeks, per protocol, were +3.5 kg (95% CI = 2.8-4.1 kg) (n = 64) in Year 1 and -0.15 kg (95% CI = -0.7-0.3 kg) (n = 87) in Year 2. Weight changes were significantly different between years, for males and females (both P < 0.001). Intention-to-treat analysis showed similar results. Relative Risk for weight gain in Year 2, compared to Year 1, was 0.5 (P < 0·0001).


CONCLUSIONS
Calorie-labeling was associated with a 3.5 kg less weight gain, representing a low-cost "nudging" approach to combat the rapid weight gain seen in young adults.
Human Nutrition Section, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow Royal Infirmary, Glasgow, UK.
Charoula Konstantia
CK
Nikolaou
Catherine Ruth
CR
Hankey
Michael Ernest John
ME
Lean
D000293:Adolescent; D000328:Adult; D001835:Body Weight; D002149:Energy Intake; D005006:Ethnicity; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D005515:Food Labeling; D006801:Humans; D065186:Interrupted Time Series Analysis; D008297:Male; D009765:Obesity / Q000178:diet therapy / Q000453:epidemiology / Q000517:prevention & control*; D015430:Weight Gain; D055815:Young Adult