Passive overconsumption? Limited evidence of compensation in meal size when consuming foods high in energy density: Two randomised crossover experiments.

Research has drawn contradictory conclusions as to whether humans adjust meal size based on meal energy density (ED) or exhibit 'passive overconsumption'. Recent observational research has suggested that meal EDs greater than 1.7-2 kcal/g are compensated for through consumption of smaller meal sizes. We tested the relationship between ED and meal size by examining energy intake of meals at three levels of ED: low (∼1.0 kcal/g), medium (1.7-2.0 kcal/g) and high (>3.0 kcal/g). Two randomised, crossover experiments were conducted with adult participants. In experiment 1 (n = 34, 62% female, mean age 37.4 years), participants were served a lunch including a familiar low, medium or high ED dessert to eat ad libitum. In experiment 2 (n = 32, 66% female, mean age 36.4 years), participants were served a lunch meal manipulated to be low, medium or high ED to eat ad libitum. For experiment 2, later energy intake (post-meal energy intake) was also measured. In experiment 1, participants consumed a similar amount of energy from the low vs. medium ED food. The high ED food was associated with an increased intake of approximately 240 kcals compared to medium (p < 0.001, Cohen's d = 2.31) and low (p < 0.001, Cohen's d = 4.42) ED foods. In experiment 2, there were no significant differences in meal size (grams) between ED meals, resulting in a largely linear relationship between meal ED and energy intake across the three ED conditions ('passive overconsumption'). There were no differences in later energy intake between ED conditions. Contrary to recent suggestions, foods higher in ED were not associated with adjustments to meal size and were associated with increased energy intake across two experiments. Reformulation of foods high in ED may be an effective population level approach to reducing energy intake and obesity. Clinical trial registry number: NCT05744050; https://clinicaltrials.gov/ct2/show/NCT05744050.