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Trial registered on ANZCTR


Registration number
Help: Registration number
ACTRN12626000976381p
Ethics application status
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Not yet submitted
Date submitted
Help: Date submitted
20/07/2026
Date registered
Help: Date registered
7/08/2026
Date last updated
Help: Date last updated
7/08/2026
Date data sharing statement initially provided
Help: Data sharing statement date
7/08/2026
Type of registration
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Prospectively registered

Titles & IDs
Public title
Matrix Matters: The Role of Intrinsic Beef Fat in Modulating Postprandial Muscle Protein Synthesis in Humans
Scientific title
Matrix Matters: The Role of Intrinsic Beef Fat in Modulating Postprandial Muscle Protein Synthesis in Humans
Additional trial identifiers [1] 317962 0
Nil
Universal Trial Number (UTN)
Trial acronym
Related trial records

Health condition
Health condition(s) studied:
Muscle protein synthesis 342928 0
Condition category
Condition code
Musculoskeletal 339048 339048 0 0
Normal musculoskeletal and cartilage development and function

Intervention/exposure
Study type
Interventional
Description of the intervention or exposure
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.
Intervention code [1] 334830 0
Treatment: Other
Description of the comparator or control
The lean steak treatment is to be considred the comparator treatment.
Control group
Active

Outcomes
Primary outcome [1] 346290 0
Muscle protein fractional synthesis rate (FSR)
Timepoint [1] 346290 0
Muscle biopsies collected at -120, 0, and 300 minutes during each experimental trial. Times are listed relative to meal consumption (i.e. -120min is 120min prior to meal, 0min is baseline/immediately pre-meal etc.).
Secondary outcome [1] 465323 0
Muscle anabolic signalling
Timepoint [1] 465323 0
Muscle biopsies collected at -120, 0, and 300 minutes during each experimental trial. Times are listed relative to meal consumption (i.e. -120min is 120min prior to meal, 0min is baseline/immediately pre-meal etc.).
Secondary outcome [2] 465324 0
Stable isotope tracer enrichment (single outcome).
Timepoint [2] 465324 0
Throughout each experimental trial during isotope infusion (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [3] 465325 0
Total amino acids (sum of all quantified amino acids: Alanine, Arginine, Aspartic acid, Cysteine, Glutamic acid, Glycine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Proline, Serine, Threonine, Tyrosine, Valine, Tryptophan) - composite outcome
Timepoint [3] 465325 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [4] 465326 0
Total saturated fatty acids
Timepoint [4] 465326 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, 0, 15, 30, 45, 60, 90, 120, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [5] 465327 0
Plasma insulin concentration
Timepoint [5] 465327 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [6] 465328 0
Plasma triglyceride concentrations
Timepoint [6] 465328 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, 0, 15, 30, 45, 60, 90, 120, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [7] 465329 0
Gastrointestinal symptoms
Timepoint [7] 465329 0
Completed at -30, 0, 30, 60, 90, 120, 150, 180, 240, 300 minrelative to meal consumption where 0 = baseline/immediately pre-meal.
Secondary outcome [8] 465330 0
Appetite questionnaire
Timepoint [8] 465330 0
Completed at -30, 0, 30, 60, 90, 120, 150, 180, 240, 300 minrelative to meal consumption where 0 = baseline/immediately pre-meal.
Secondary outcome [9] 465331 0
Meal acceptability questionnaire
Timepoint [9] 465331 0
This will be completed once immediately post-meal, and again after 180 and 300 min post-meal
Secondary outcome [10] 465640 0
Branched-chain amino acids (Isoleucine + Leucine + Valine) - composite outcome
Timepoint [10] 465640 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [11] 465641 0
Essential amino acids (Histidine + Isoleucine + Leucine + Lysine + Methionine + Phenylalanine + Threonine + Valine + Tryptophan) - composite outcome
Timepoint [11] 465641 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [12] 465642 0
Non-essential amino acids (Alanine + Arginine + Aspartic acid + Cysteine + Glutamic acid + Glycine + Proline + Serine + Tyrosine) - composite outcome
Timepoint [12] 465642 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [13] 465643 0
Alanine
Timepoint [13] 465643 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [14] 465644 0
Arginine
Timepoint [14] 465644 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [15] 465645 0
Aspartic acid
Timepoint [15] 465645 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [16] 465646 0
Cysteine
Timepoint [16] 465646 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [17] 465647 0
Glutamic acid
Timepoint [17] 465647 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [18] 465648 0
Glycine
Timepoint [18] 465648 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [19] 465649 0
Histidine
Timepoint [19] 465649 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [20] 465650 0
Isoleucine
Timepoint [20] 465650 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [21] 465651 0
Leucine
Timepoint [21] 465651 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [22] 465652 0
Lysine
Timepoint [22] 465652 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [23] 465653 0
Methionine
Timepoint [23] 465653 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [24] 465654 0
Phenylalanine
Timepoint [24] 465654 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [25] 465655 0
Proline
Timepoint [25] 465655 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [26] 465656 0
Serine
Timepoint [26] 465656 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [27] 465657 0
Threonine
Timepoint [27] 465657 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [28] 465658 0
Tyrosine
Timepoint [28] 465658 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [29] 465659 0
Valine
Timepoint [29] 465659 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [30] 465660 0
Tryptophan
Timepoint [30] 465660 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, -150, -120, -90, -60, -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [31] 465661 0
Total monounsaturated fatty acids
Timepoint [31] 465661 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, 0, 15, 30, 45, 60, 90, 120, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [32] 465662 0
Total polyunsaturated fatty acids
Timepoint [32] 465662 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, 0, 15, 30, 45, 60, 90, 120, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [33] 465663 0
Total omega-3 fatty acids
Timepoint [33] 465663 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, 0, 15, 30, 45, 60, 90, 120, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [34] 465664 0
Total omega-6 fatty acids
Timepoint [34] 465664 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, 0, 15, 30, 45, 60, 90, 120, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [35] 465665 0
Omega-6 to omega-3 ratio
Timepoint [35] 465665 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, 0, 15, 30, 45, 60, 90, 120, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).
Secondary outcome [36] 465666 0
Total fatty acids
Timepoint [36] 465666 0
Serial pre and postprandial blood samples throughout each experimental trial (-180, 0, 15, 30, 45, 60, 90, 120, 180, 240, 300 min relative to meal consumption where 0 = baseline/immediately pre-meal).

Eligibility
Key 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.
Minimum age
18 Years
Maximum age
35 Years
Sex
Both males and females
Healthy volunteers
Yes
Key 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

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation is not concealed
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation of order using computer generated sequences.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
The primary outcome is integrated postprandial myofibrillar FSR (%/h). Prior data indicate a detectable mean difference of 0.01%/h (SD 0.013 %/h), requiring 14 participants per pairwise comparison (paired t-test, a < 0.05, power > 0.80). In this crossover design, 21 completions provide adequate power. To account for dropout, 24 participants will be recruited.

Data Analysis will be carried out by a biostatistician that is blinded to treatments and order of administration. A primary analysis of intention to treat (ITT) will be conducted of all the participants that have completed the trial. Between-group (treatment) comparisons will be made using linear mixed models with a fixed effect of treatment and a random intercept for participant, adjusting for baseline outcome level within each session). Outcome variables will be log-transformed where necessary to satisfy parametric assumptions. All tests will be two-tailed with statistical significance set at p < 0.05.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
1/02/2027
Actual
Date of last participant enrolment
Anticipated
1/11/2027
Actual
Date of last data collection
Anticipated
31/12/2027
Actual
Sample size
Target
24
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
VIC

Funding & Sponsors
Funding source category [1] 322512 0
Commercial sector/Industry
Name [1] 322512 0
National Cattlemen's Beef Association
Country [1] 322512 0
United States of America
Primary sponsor type
University
Name
Deakin University
Address
Country
Australia
Secondary sponsor category [1] 325432 0
Commercial sector/Industry
Name [1] 325432 0
National Cattlemen's Beef Association
Address [1] 325432 0
Country [1] 325432 0
United States of America

Ethics approval
Ethics application status
Not yet submitted
Ethics committee name [1] 320997 0
Deakin University Human Research Ethics Committee (DUHREC)
Ethics committee address [1] 320997 0
Ethics committee country [1] 320997 0
Australia
Date submitted for ethics approval [1] 320997 0
31/08/2026
Approval date [1] 320997 0
Ethics approval number [1] 320997 0

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 152306 0
Dr Lee Hamilton
Address 152306 0
Deakin University, 75 Pigdons Road, Waurn Ponds, Victoria 3216
Country 152306 0
Australia
Phone 152306 0
+61 3 924 45207
Fax 152306 0
Email 152306 0
[email protected]
Contact person for public queries
Name 152307 0
Charles Urwin
Address 152307 0
Deakin University, 221 Burwood Highway, Burwood, 3125, Victoria
Country 152307 0
Australia
Phone 152307 0
+61 3 924 68958
Fax 152307 0
Email 152307 0
[email protected]
Contact person for scientific queries
Name 152308 0
Charles Urwin
Address 152308 0
Deakin University, 221 Burwood Highway, Burwood, 3125, Victoria
Country 152308 0
Australia
Phone 152308 0
+61 3 924 68958
Fax 152308 0
Email 152308 0
[email protected]

Data sharing statement
Will the study consider sharing individual participant data?
No


What supporting documents are/will be available?

No Supporting Document Provided


Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.