A study protocol for a randomised controlled trial assessing the effects of daily supplementation with defatted almond protein powder on fitness training adaptations and metabolic health in overweight and obese post-menopausal women

Background: Sarcopenia, characterised by declines in muscle mass and function, is expected to impact many postmenopausal women due to ageing and sedentary lifestyles. Hormonal changes during menopause exacerbate loss of lean mass, visceral fat gain, and risk of cardiometabolic disease. Resistance and high-intensity interval training (HIIT) are effective countermeasures, with adequate protein and fibre intake supporting favourable adaptations. However, many women fall short of recommendations, particularly at breakfast. Defatted almond protein powder (APP), a by-product of almond oil production, is rich in protein and fibre and may enhance exercise-induced adaptations, though its effects remain untested. Methods: This protocol outlines a 12-week study comprising a 10-week supervised resistance and high-intensity interval training (HIIT) intervention, preceded and followed by baseline and post-intervention assessments conducted over a one-week period each. The randomised, double-blind, placebo-controlled trial will investigate the effects of defatted almond protein powder supplementation in postmenopausal women. We aim to recruit 48 participants who will be randomly allocated to receive either APP or an energy-matched placebo (maltodextrin). Primary outcomes include changes in total and regional lean mass which will be assessed using dual-energy X-ray absorptiometry (DXA). Secondary outcomes include strength (3-RM, chest press, leg press and handgrip strength), cardiovascular fitness (VO₂peak), total body fat (absolute and %), blood lipids, blood glucose, insulin response, appetite, supplement acceptability and dietary intake. Data will be analysed using linear regression and mixed-effects models under intention-to-treat and per-protocol frameworks. Discussion: This study will be the first to examine the effects of daily supplementation with APP on musculoskeletal and metabolic outcomes in postmenopausal women undergoing structured and supervised exercise training. Findings of this study may assist in developing applications for high protein/fibre by-product from the nut/seed oil industry and determine if supplementation with this almond derived product is an effective nutritional strategy to support training adaptations to strength and HIIT training in ageing women. Trial Registration: Clinical Trials Registry (ANZCTR: ACTRN12625000133437). Almond protein, menopause, sarcopenia, resistance training, high-intensity interval training, cardiometabolic health, plant-based protein, dietary fibre