Even though intention and planning are predictors of dietary change, they operate differently under specific conditions (level of social support), for specific subgroups (men vs. women), and for different target behaviors (fruit vs. vegetable intake). These results suggest to further examine the mechanisms by which intentions are translated into behavior via planning.

Intention and planning are key predictors of dietary change. However, these variables work better under specific conditions (with a sufficient level of autonomy), and differently in subgroups (men vs. women). These results may explain the inconsistent findings of previous studies on the mediating effect of planning and allow for a better description of the mechanisms by which intentions may influence behaviour. Statement of contribution What is already known on this subject? The adoption of health-enhancing dietary behaviours can be facilitated by intentions and planning. Planning to eat more fruit and vegetable helps to translate intentions into actual consumption. Fruit and vegetable intake levels are higher in women than in men. What does this study add? Dietary intentions engender more likely planning processes when perceived autonomy concerning food consumption is high. Dietary autonomy beliefs and sex moderate the intention-planning-behaviour chain. Among men, dietary planning is highest when both intentions and autonomy are high.