Abstract

Objectives

Laboratory studies demonstrate positive associations between hunger and appetite with energy intake, but these findings are inconsistent in free-living conditions. We investigated if internal sustenance cues (hunger, appetite, thirst) were associated with energy intake in laboratory and free-living conditions, with participants aware of being recorded with wearable cameras. We also explored if BMI modified these associations.

Methods

Fifty-nine participants (mean BMI ± SD: 31.2 ± 8.5 kg/m2) enrolled for one day, donning a wearable necklace camera to record eating behaviors. Participants were asked to consume meals (breakfast, lunch, dinner) and snacks ad libitum, with all items weighed pre- and post-intake. Participants were able to leave with snacks, provided they returned with the packaging and reported it to the team. Before each meal, participants reported their internal sustenance cues using 100-mm visual analogue scales; higher scores indicated stronger cues. Nutrition Data System for Research was used to analyze diet data. Multiple linear regression models, adjusted for BMI, were performed to examine associations between pre-meal internal sustenance cues and meal-level energy intake, as well as the interaction between BMI and internal sustenance cues (R ver4.4.1).

Results

Stronger pre-breakfast internal sustenance cues were significantly associated with higher energy intake at breakfast (all p < 0.05). At pre-dinner, stronger hunger and appetite cues were significantly associated with higher energy intake (β = 3.9 ± 1.8 and 7.1 ± 2.0, p < 0.05). There were statistically significant interactions between pre-lunch hunger and pre-dinner thirst with BMI, revealing that these associations depend on BMI (both p < 0.05). No other statistically significant associations were observed in the main or interaction analyses.

Conclusions

Eating time has a crucial role in the association between internal sustenance cues and energy intake, shown in both laboratory and free-living conditions. BMI also served as an effect modifier, warranting further investigation of how internal cues and obesity interact to impact energy intake.

Funding Sources

NIDDK R01DK129843.