Mood and appetite: Their relationship with discretionary and total daily energy intake

Negative affect is shown consistently to promote unhealthy food choices and dietary intake in laboratory studies. However, this relationship in naturalistic settings is less clear and previous research is limited by dietary assessment methodology and neglects to account for several important moderating variables. This observational study aimed to examine the association of negative affect and other psychological factors associated with eating behaviour simultaneously with discretionary energy intake and total energy intake, and whether these were moderated by emotional eating predisposition or age, sex and weight status.

One hundred adults completed a four-day food diary, a concurrent end-of-day questionnaire that assessed daily affect and experience of appetite, and the Three Factor Eating Questionnaire to assess trait eating behaviour. Food diaries provided data on participants' daily intake of total energy and of "discretionary items" (specific energy-dense and nutrient poor foods and beverages as defined by the Australian Guide to Healthy Eating). Stepwise random effects models were used to estimate the association of end-of-day ratings, trait eating behaviour and personal factors, and their interactions, with discretionary and total energy intake.

Daily rated negative affect and appetite were significantly and positively associated with discretionary intake, such that a one unit increase in each scale was associated with eating 139 kJ/d [SE 61] and 194 kJ/d [SE 68] more discretionary energy, respectively. Negative affect and its interaction with emotional eating were consistently, positively associated with discretionary energy intake. This relationship was strongest in younger participants (β = -4.9 [SE 2.2], p < .05). There was no interaction with sex or weight status. Total energy intake was not associated with negative affect nor its interaction with emotional eating but was consistently associated with appetite.

When personal factors (age, sex, BMI), trait eating behaviours and daily rated negative affect and appetite are considered simultaneously, daily discretionary intake is associated most strongly with negative affect. Individuals, particularly young adults, may be more likely to overeat discretionary energy on days that negative affect is rated more highly. However, this may not necessarily translate into greater total energy intake which was most consistently associated with daily rated appetite.