Introduction: Compensatory increases in hunger and changes to food preferences in response to energy restriction may reduce weight loss efficacy. Increasing dietary protein could moderate these adaptive responses. The aim of this study was to determine if adding dietary protein during energy balance and energy restriction reduces compensatory increases in hunger and changes in preferences for energy-dense foods.
Methods: 22 Participants (11 M, 11 F) undertook the study. The study involved 4 dietary treatments, each 2 weeks in duration: habitual diet 1 (HD1), habitual diet 2 (HD2), high protein energy balance (HPEBal: energy balance while increasing protein by 0.5g/kg/day with a protein supplement) and high protein energy restriction (HPER: increasing protein by 0.5g/kg/day with a protein supplement while reducing energy intake by 33%). Appetite and L & W were measured during 11hr probe days at the end of each treatment.
Results: Total day hunger significantly increased and fullness decreased during HPER compared to HD1, HD2 and HPEBal (P < 0.01). Satiety quotient did not differ between the conditions. There was no relationship between protein intake (grams, g/kg/day, or % energy intake) and changes in hunger in response to HPEBal or HPER. There were significant increases in explicit wanting for high fat savoury and high fat sweet foods during HPER compared to HD1 (p<0.05).
Conclusions: Increasing dietary protein by 0.5g/kg/day did not significantly mediate the compensatory changes in appetite and food preferences commonly reported during energy restriction.