Influences of Public Health Policies on Individuals' Dietary Behaviours: A Large Cohort Study from Chile

The Chilean law of food labeling and advertising was promulgated in 2012 and was implemented in consecutive phases until 2019.

To determine the change in dietary behaviour experienced by the participants of a large Chilean cohort and to identify predictors of change.

The sample included 2.608 adults between 35 and 70 years old recruited between 2006 and 2009 and followed on average over 10.8 years. Food intake was measured using a validated Food Frequency Questionnaire twice, at baseline, between June 2006 and October 2009, and after ten years of follow-up, between March 2018 and October 2019. The modified Alternative Healthy Eating Index (mAHEI) assessed participants' diet quality. Also, other socio-demographic and health variables were measured.

During follow-up, the composition of the diet changed with an increase in the consumption of carbohydrates and fats and a decrease in the consumption of proteins. Also, 31.6% of participants improved their diet quality, but it worsened among 32.6% of participants. Being female, having a major health event, having a high educational level, and having sufficient household income were predictors for positive diet quality changes.

During ten years of follow-up, the majority of participants did not improve their eating habits. Predictors of positive change were essentially the socio-demographic background and the occurrence of health events. Our findings suggest that it is necessary to reinforce policies related to diet with even more profound interventions than those already implemented.