Lack of effect of high-protein vs. high-carbohydrate meal intake on stress-related mood and eating behavior

Background: Consumption of meals with different macronutrients, especially high in carbohydrates, may influence stress-related eating behavior. We aimed to investigate whether consumption of high-protein vs. high-carbohydrate meals influences stress-related mood, food reward, i.e. 'liking' and 'wanting', and post-meal energy intake. Methods: Participants (n = 38, 19m/19f, age = 25 +/- 9 y, BMI = 25.0 +/- 3.3 kg/m(2)) came to the university four times, fasted, once for a stress session receiving a high-protein meal, once for a rest session receiving a high-protein meal, once for a stress session receiving a high-carbohydrate meal and once for a rest session receiving a high-carbohydrate meal (randomized cross-over design). The high-protein and high-carbohydrate test meals (energy percentage protein/carbohydrate/fat 65/5/30 vs. 6/64/30) matched for energy density (4 kJ/g) and daily energy requirements (30%). Stress was induced using an ego-threatening test. Pre- and post-meal 'liking' and 'wanting' (for bread, filling, drinks, dessert, snacks, stationery (non-food alternative as control)) was measured by means of a computer test. Following the post-meal 'wanting' measurement, participants received and consumed their wanted food items (post-meal energy intake). Appetite profile (visual analogue scales), mood state (Profile Of Mood State and State Trait Anxiety Inventory questionnaires), and post-meal energy intake were measured. Results: Participants showed increased feelings of depression and anxiety during stress (P < 0.01). Consumption of the test meal decreased hunger, increased satiety, decreased 'liking' of bread and filling, and increased 'liking' of placebo and drinks (P < 0.0001). Food 'wanting' decreased pre- to post-meal (P < 0.0001). The high-protein vs. high-carbohydrate test meal induced lower subsequent ` wanting' and energy intake (1.7 +/- 0.3 MJ vs. 2.5 +/- 0.4 MJ) only in individuals characterized by disinhibited eating behavior (factor 2 Three Factor Eating Questionnaire, n = 16), during rest (P <= 0.01). This reduction in ` wanting' and energy intake following the high-protein meal disappeared during stress. Conclusions: Consumption of a high-protein vs. high-carbohydrate meal appears to have limited impact on stress-related eating behavior. Only participants with high disinhibition showed decreased subsequent ` wanting' and energy intake during rest; this effect disappeared under stress. Acute stress overruled effects of consumption of high-protein foods.