(P32-001-23) Essential Amino Acid-Enriched Diets Alter Perceived Appetite and Fullness Without Diminishing Energy Intake During Arctic Military Training

Objectives: Consuming essential amino acid (EAA)-enriched protein has been studied as a potential countermeasure to muscle loss during periods of energy deficit resulting from strenuous military training. Whether the satiating effect of increased dietary protein suppresses ad libitum energy intake under these conditions is unknown. This study aimed to determine the effects of EAA-enriched protein, high-fat energy-dense (EN-DENSE) or high carbohydrate (CON) supplemental nutrition on perceived appetite and energy intake during military training.

Methods: Soldiers (n=68) completing 8 days of arctic training were randomized to receive three combat rations and four EAA (31 g protein, 4.2 kcal/g), EN-DENSE (35 g fat, 6.7 kcal/g), or CON (70 g carbohydrate, 3.4 kcal/g) supplemental bars (~375 kcal/bar) daily. Soldiers were instructed to eat all bars provided and consume rations ad libitum. Energy expenditure (D₂¹⁸O) and intake (food log/wrapper collection) were measured daily. Perceived hunger, fullness, prospective consumption (PC), and desire to eat (DtE) were assessed (100 mm visual analogue scales) before (PRE) and after the training (POST).

Results: Ration (2733±648 vs. 3008±584 vs. 2940±438 kcal/d; mean ± SD) and supplement (1163 ± 331 vs. 1156±336 vs. 1186±241 kcal/d) intake did not differ (P >0.05) between EAA, EN-DENSE and CON. There was no difference in energy expenditure (5341±674 kcal/d) or energy deficit (-1257±599 kcal/d) between groups. Protein, fat, and carbohydrate intakes (g/kg/d) were highest (P < 0.05) in EAA (2.5±1.5), EN-DENSE (2.7±0.6) and CON (7.9±1.0), respectively. Hunger increased (P=0.007) from PRE to POST (48±23 vs. 54±18 mm) in all groups, while PC and DtE did not change. Fullness was greater (P=0.046) in EAA compared with EN-DENSE at POST (54±18 vs. 42±15 mm). Appetite (mm) increased (P=0.002) from PRE to POST in EN-DENSE (57±13 vs. 67±13) and CON (56±12 vs. 63±12) but did not change in EAA (61±10 vs. 59±12).

Conclusions: While consuming EAA-enriched protein suppressed appetite and increased fullness compared with high-fat energy-dense and high-carbohydrate supplements, this did not reduce energy intake. These findings suggest it is possible to optimize dietary protein content without worsening energy deficits during strenuous military training.

Funding Sources: DHP JPC-5