The Formation and Malleability of Dietary Habits: A Field Experiment with Low Income Families

In the first intervention, families received groceries at home to prepare healthy meals. In the second intervention, families were asked to avoid snacking. Families were asked to stick to these protocols for 12 weeks. Our interventions are unique in two ways: First, the interventions we consider are relatively long and probably at the upper end of what one could think of implementing. The hope was that these interventions would result in long-lasting changes in their habits and reduce the chances their children become obese as they grow up. Second, we target very young children (2 to 6-year-old), at an age where dietary habits are presumably more malleable, and we involve the whole family in the intervention.

We evaluated these interventions over the course of 3 years by comparing the families exposed to the interventions to a control group of families asked to carry on as usual. We found a large and significant effect on children’s body mass index, an effect that persists over time for the first intervention but fades away for the second. The mechanism for the change appears to be a reduction in consumption of sugary foods. We did not find that children developed a stronger taste for healthy foods, or were less attracted by sweets or chips... So, the effect seems to have been driven by parents limiting access to foods high in sugar. The parents themselves did however not change their habits at all and the interventions appeared to have no impact on their weight or health.