None listed
Conditions
Brief summary
Our proposed study will address this gap by comparing postprandial muscle protein synthesis in response to iso-nitrogenous beef meals varying in fat content and structure: lean steak, higher-fat steak, and lean steak with added rendered tallow. We will assess this in the rested state, which better reflects typical feeding patterns and avoids confounding from exercise-enhanced responses.
Interventions
What is the intervention?
Participants will complete three experimental conditions in a randomized crossover design, consuming a single iso-nitrogenous beef meal per visit: (1) lean steak, (2) higher-fat steak, or (3) lean steak with added rendered tallow. During each trial, participants will undergo a stable isotope tracer infusion, serial blood sampling, three muscle biopsies, and completion of appetite and meal satisfaction questionnaires. Meals will be consumed within 15 minutes.
Compositio
What is the intervention? Participants will complete three experimental conditions in a randomized crossover design, consuming a single iso-nitrogenous beef meal per visit: (1) lean steak, (2) higher-fat steak, or (3) lean steak with added rendered tallow. During each trial, participants will undergo a stable isotope tracer infusion, serial blood sampling, three muscle biopsies, and completion of appetite and meal satisfaction questionnaires. Meals will be consumed within 15 minutes. Composition of the meals are as follows: Lean Steak Treatment: 142g steak, 100g mashed potato, 40g maltodextrin [protein content = 32g, fat content = 6.3g, carbohydrate content = 57g, energy = 452 kcal]. Higher Fat Steak Treatment: 160g steak, 100g mashed potato [protein content = 32g, fat content = 26.3g, carbohydrate content = 17g, energy = 452 kcal]. Lean Steak + Added Fat Treatment: 142g steak, 100g mashed potato, 20g tallow [protein content = 32g, fat content = 26.3g, carbohydrate content = 17g, energy = 452kcal]. Who delivers it and their relevant expertise? The study will be delivered by the research team at Deakin University. Muscle biopsies will be performed by A/Prof. Andrew Garnham, an experienced physician with extensive expertise in the percutaneous muscle biopsy technique. Stable isotope infusions, cannulation, blood collection, DXA scanning, meal preparation, and physiological testing will be conducted by trained researchers and qualified health professionals with relevant certifications and experience in clinical research procedures. How is it delivered? All procedures are conducted individually, face-to-face, in a controlled laboratory setting. Test meals are consumed under direct supervision, and all clinical procedures are performed by trained personnel. How often and for how long? Participants will attend four visits: one baseline assessment visit and three experimental trial visits. Experimental visits are separated by a minimum three-week washout period. Each trial visit lasts approximately 8 hours, including isotope infusion, meal consumption, biological sample collection, and postprandial monitoring. Where is it delivered? The study will be conducted at the Physiology Laboratory and food preparation laboratory at Deakin University, Burwood Campus. Adherence (e.g. reminders, monitoring) Participants will receive written and verbal instructions regarding pre-trial dietary and physical activity standardization and will be provided with a standardized evening meal before each trial. Food and activity diaries will be used to monitor compliance, and adherence will be confirmed verbally on arrival. All intervention meals will be consumed under direct researcher supervision, ensuring complete consumption and protocol compliance.
Sponsors
Deakin University
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
Healthy adults (18-35 y), mixed-sex, who are strength trained (2 or more sessions per week for 6+ months) and active (accumulating 75-150 min per week of moderate to vigourous physical activity), and can attend all testing sessions.
Exclusion criteria
• Vegetarian, vegan, or avoidance of beef • Allergy or intolerance to beef or study foods • Gastrointestinal, metabolic, endocrine, cardiovascular, renal, hepatic, or musculoskeletal disease • Use of medications or supplements known to affect protein metabolism, appetite, inflammation, or muscle mass • Pregnancy or breastfeeding • Current injury preventing normal training • Recent major surgery • Use of anticoagulants or history of bleeding disorder • Allergy to local anaesthetic or contraindication to muscle biopsy • Excess alcohol intake or recreational drug use • Participants with phenylketonuria (PKU) or any condition affecting phenylalanine metabolism
Outcome results
None listed