In recent years, policy statements related to obesity have acknowledged the utility of dietary energy density as a guide to food choices
The World Health Organization recommends reducing the energy density of the diet as a strategy to stem the global obesity epidemic. Reductions in energy density can be achieved by increasing intake of vegetables and fruits. Their high water content allows people to eat satisfying amounts of food with few calories per bite. Filling up at the start of a meal with vegetables or fruit and increasing the proportion of vegetables in a main course have been found to control hunger and moderate energy intake. Thus, a number of studies show that eating vegetables and fruits can lower the energy density of a meal and this in turn can reduce energy intake.
Can we extrapolate from these short-term studies and promote increased consumption of vegetables and fruits for weight loss? While several recent studies support this suggestion, the current body of evidence is small and the results have been inconsistent. Most studies of the relationship between vegetable and fruit consumption and weight status have not assessed the impact on dietary energy density, and have not controlled for critical variables that could affect intake such as preparation method, type of fruit or vegetable, timing of consumption, or whether they are added to the diet or substituted for other ingredients.
Eating more vegetables and fruits could provide consumers with a powerful tool to control their weight while improving the quality of their diets. However, additional strategic investigations of how to use vegetables and fruits to lower dietary energy density, to enhance satiety, and to influence energy balance are needed for the development of effective, evidence-based consumer messages.