Hospitalization often involves long periods of bed rest and reduced nutritional intake, which can lead to skeletal muscle loss and anabolic resistance. These effects slow recovery and increase the risk of complications, long-term disability and healthcare costs. Animal-based proteins are effective at stimulating muscle protein synthesis (MPS) because they contain all essential amino acids and have high bioavailability, but they are less sustainable. Plant-based proteins are more environmentally friendly but may be less effective for MPS due to lower essential amino acid content and lower digestibility. Combining different plant proteins may improve their quality, yet their impact during bed rest is still unclear. Neuromuscular electrical stimulation (NMES) may help counteract anabolic resistance by mimicking exercise, but its long-term effects in bedridden individuals are not well studied.

This prospective, randomized, controlled trial aims to assess the effects of a nutritional intervention (plant-dominant versus dairy-based protein) and a physical stimulus (NMES versus non-NMES) on MPS during 4 days of bed rest in healthy young adults.

Inclusion Criteria:

• Healthy (assessed based on routine medical questionnaire)
• Male and female sexes
• Aged between 18 and 35 years inclusive
• BMI between 18.5 and 30.0 kg/m²

Exclusion Criteria:

• Vegan diet
• Allergies or intolerance to cow's milk products, fish, soy, and/or pea protein
• Galactosemia
• Smoking on a weekly basis (i.e., every week)
• Diagnosed diabetes mellitus
• Chronic corticosteroid use
• Severe kidney and/or liver failure
• Dialysis
• Bleeding disorders, including anticoagulant and antiplatelet therapy
• Currently pregnant