PURPOSE:: To determine if protein supplementation (PRO) prior to an acute bout of heavy resistance training (HRT) would influence post-exercise resting energy expenditure (REE) and the non-protein respiratory exchange ratio (RER). Hypothesis: REE would be increased and RER would be decreased up to 48 hours following timed PRO and HRT compared to carbohydrate supplementation (CHO) and HRT. METHODS:: Eight resistance-trained subjects (5M, 3W) participated in a double-blind, two trial crossover design, where REE and RER were measured (7:00am) on four consecutive days. On the second day of trial one, subjects consumed 376 KJ of either PRO (18g whey protein, 2g carbohydrate, 1.5g fat) or CHO (1g whey protein, 19g carbohydrate, 1g fat) 20 minutes prior to a single bout of HRT (9 exercises, 4 sets, 70-75% 1RM). REE and RER were measured 24 and 48 hours post-HRT. During trial two, the same protocol was followed except subjects consumed the second supplement prior to HRT. RESULTS:: Compared with baseline, REE was elevated significantly in both CHO and PRO at 24 and 48 hours post-HRT (p < 0.05). At 24 hours post-HRT, REE in response to PRO was significantly greater compared to CHO (p < 0.05). RER decreased significantly in both CHO and PRO at 24 hours post-HRT compared to baseline (p < 0.05). No differences were observed in total energy intake, macronutrient intake, or HRT volume (p > 0.05). CONCLUSION:: Timing PRO prior to HRT may be a simple and effective strategy to increase energy expenditure by elevating REE the day after HRT. Increasing REE could facilitate reductions in body fat mass and improve body composition if nutritional intake is stable.