Can changing the position of online menu items increase selection of fruit and vegetable snacks? A cluster randomized trial within an online canteen ordering system in Australian primary schools.

Background: Manipulating the position of food items within the physical food environment has consistently been found to influence item selection. However, the extent to which this strategy is effective in an online food environment is unknown.

Objective: This study investigated whether an intervention to position fruit and vegetable snack items as the first and last menu items in an online school canteen ordering system increased the selection of those items.

The Effect of Medical Marijuana Laws on Body Weight.

This study is the first to examine the effects of medical marijuana laws (MMLs) on body weight, physical wellness, and exercise. Using data from the 1990 to 2012 Behavioral Risk Factor Surveillance System and a difference-in-difference approach, we find that the enforcement of MMLs is associated with a 2% to 6% decline in the probability of obesity. We find some evidence of age-specific heterogeneity in mechanisms.

Within-family variation in obesity.

We use data from the Children of the National Longitudinal Survey of Youth 1979 to document the degree to which childhood obesity varies among siblings. We find considerable differences in body weight between siblings with over half of the siblings differing by more than 20 age-specific percentiles in terms of the body mass index. Even among identical twins, there is an average BMI difference of 12 percentiles.