Do I need to eat immediately after training or the gains are lost?

No. The 'anabolic window' — the idea that muscles are uniquely receptive to protein only in the 30–60 minutes after a workout — was derived from studies comparing fed versus fasted training conditions, not well-nourished participants eating at different time points. Aragon and Schoenfeld (2013) reviewed the literature and concluded that the post-exercise window is far wider than popular belief suggests, and Schoenfeld's 2017 PeerJ meta-analysis confirmed that when total protein is equated, training proximity adds no significant advantage. If you trained without eating for 4+ hours beforehand, eating within an hour post-session makes sense. If you had a protein-containing meal 1–2 hours before training, total daily intake matters far more than the post-workout clock.

How much protein do I need per day for muscle building?

For most resistance-training adults, 1.6–2.2 g per kilogram of bodyweight per day represents the evidence-supported range for maximising muscle protein synthesis responses (Morton 2018 BJSM meta-analysis; ISSN 2017 Jäger position stand). Going above 2.2 g/kg provides no additional benefit for muscle gain but is not harmful in healthy adults with normal kidney function. For a 75 kg person, this is approximately 120–165 g per day. Distributing this across 4 meals of 30–40 g each, rather than consuming most in one sitting, is supported by evidence on leucine thresholds and MPS stimulation. Higher-quality proteins (whey, casein, eggs, chicken) generally provide a higher leucine content per gram of protein, which matters for MPS activation.

What is the leucine threshold and why does it matter?

Leucine is the amino acid that acts as the primary trigger for mTOR/mTORC1 activation — the anabolic signalling pathway that drives muscle protein synthesis (MPS). Research suggests that approximately 2.5–3 g of leucine per serving is required to maximally activate MPS. A standard 25 g serving of whey protein provides roughly 2.7–3 g of leucine, which is why 25–30 g of high-quality protein per meal is the commonly cited threshold. Plant-based proteins typically have lower leucine concentrations per gram of total protein (e.g. soy ~8% leucine vs whey ~10–11%), which is why plant-protein servings often need to be 30–40 g to achieve the same leucine dose. Combining complementary plant proteins (rice + pea, soy + wheat) addresses both leucine and methionine/lysine balancing.

Should I take creatine and when?

Creatine monohydrate is the most extensively researched ergogenic supplement and is classified as a Group A (performance-enhancing with strong evidence) supplement by the Australian Institute of Sport. The standard approach is 3–5 g per day continuously — no loading phase is needed. A loading phase (20 g/day in 4 divided doses for 5–7 days) reaches saturation about 3 weeks earlier than gradual loading but adds no long-term benefit. Creatine timing (pre vs post workout) does not appear to matter meaningfully; the key is daily consistency. In 2026, creatine monohydrate powder costs approximately AUD 20–40 for 300 g in Australia — roughly AUD 0.20–0.35 per daily dose, making it among the most cost-effective supplements with strong supporting evidence.

Do carbohydrate timing rules apply to resistance training?

For most resistance-training adults doing 3–5 sessions per week, carbohydrate timing after exercise has minimal independent effect on muscle outcomes. What matters is meeting daily carbohydrate targets for energy and glycogen replenishment overall. The exception is endurance athletes or those training twice daily: in these athletes, rapid glycogen resynthesis (0.8–1.2 g/kg/hour of carbohydrate for the first 4 hours post-exercise, ideally combined with protein) is clinically relevant because inadequate glycogen before the next session impairs performance. For a person doing a standard 60-minute resistance session, eating a carbohydrate-containing meal within a few hours post-training (not necessarily immediately) is entirely adequate.

Sarcopenia / muscle mass optimisation — post-exercise nutrition protocol

Post-workout nutrition and protein timing — what the evidence says

By Dr HB Lo, FACRRM Reviewed 31 October 2026 11 min read

Total daily protein — not post-workout timing — drives muscle protein synthesis. For resistance-training adults, 1.6–2.2 g/kg/day across four or more meals of at least 0.4 g/kg each produces near-maximal results. The "anabolic window" closing within 30–60 minutes of training is not supported when total protein is controlled (Schoenfeld & Aragon, *PeerJ* 2017).

Creatine monohydrate 3–5 g/day is the highest-grade ergogenic supplement, working independently of timing and reaching saturation in 28 days. Carbohydrate timing matters only for endurance athletes in multiple daily sessions. Replace approximately 150% of sweat losses over 4–6 hours after sessions exceeding 60 minutes.

Post-workout nutrition is one of the most marketed areas in sports science — and one of the most misrepresented in popular media. The image of a “muscle window” slamming shut within 30 minutes of your last rep has sold enormous quantities of protein powder, but it is not an accurate summary of the current evidence. What research in this area consistently shows is that total daily protein intake, meal distribution, and long-term dietary adherence are far more important than the precise timing of any single post-exercise meal. This article maps the evidence onto a practical framework, covering the AU clinical pathway for accessing dietitian support and guidance on supplement quality.

A. Core clinical — the AU general-practice framework

Why patients come in with timing questions. Post-workout nutrition often enters the GP consultation when a patient is pursuing a specific physical goal — muscle building after bariatric surgery, lean mass retention during weight loss, sarcopenia prevention in older adults, or performance optimisation in recreational sport. The clinical entry points include:

Older adults with low muscle mass and poor protein intake (sarcopenia, ICD-10 M62.50 / M62.84).
Patients on caloric restriction diets where muscle preservation is the therapeutic goal.
Adolescents and young adults using commercial supplements, occasionally including products with contamination or prohibited substance risks.
People with special dietary patterns (plant-based, intermittent fasting) asking whether their pattern compromises recovery.

The primary lever: total daily protein. The ISSN 2017 Jäger position stand, the most cited reference on exercise protein, sets the range for maximal muscle protein synthesis support at 1.6–2.2 g/kg/day in resistance-training adults. The upper end of this range has minimal additional benefit over the lower end and is not indicated on clinical grounds; the difference is mainly practical (it becomes harder to eat that much protein without displacing other nutrients). For older adults, the PROT-AGE Study Group (2013) recommends ≥1.2–1.6 g/kg/day — higher than the population-level EAR of 0.8 g/kg/day — to overcome anabolic resistance, the blunted MPS response to protein intake seen with ageing.

Meal distribution and leucine thresholds. Total protein intake is more important than timing, but distribution matters. Research on MPS stimulation shows:

A threshold of approximately 0.4 g/kg per meal (roughly 25–40 g for most adults) is needed to maximally stimulate MPS in a single sitting.
Eating the same total protein in 1–2 large meals produces less 24-hour MPS than spreading it across 4+ meals, because the ceiling for a single MPS bout is limited.
Leucine, the branched-chain amino acid that activates mTORC1, reaches its minimum effective dose at approximately 2.5–3 g per serving, which corresponds to roughly 25 g of high-quality whey or ~35 g of most plant proteins.

This means the practical guidance is: eat 4 protein-containing meals per day, each containing at least 25–35 g of protein from a quality source (meat, fish, poultry, dairy, eggs, legumes + complementary plant proteins), rather than having one massive evening meal.

When to discuss referral to a sports dietitian. Complex scenarios warrant referral to a Sports Dietitian (accredited by Sports Dietitians Australia) or an accredited practising dietitian under a CDM plan (MBS item 10954, 5 combined visits per calendar year):

Athlete with performance goals beyond general fitness.
Older adult with established sarcopenia and poor oral intake.
Patient on meal replacement or very-low-calorie diet.
Adolescent using supplements — particularly pre-workouts, fat burners, or mass gainers with undisclosed formulas.
Gastrointestinal absorption issues affecting protein bioavailability.

B. Evidence appraisal — dismantling and re-examining the anabolic window

Historical basis. The anabolic window concept originated partly from acute MPS studies showing elevated rates of protein synthesis in the hours immediately after resistance exercise (mixed muscle protein synthesis measured by isotope tracer infusion). These studies led to the inference that protein consumed immediately post-exercise would capitalise on this window. The inference was plausible but overlooked an important confound: most studies confirming the window used fasted participants.

The Aragon & Schoenfeld (2013) review. This narrative review in the Journal of the International Society of Sports Nutrition examined the existing RCT and mechanistic literature and argued that:

The post-exercise anabolic window is at least 4–6 hours wide (not 30–60 min) in fed individuals.
If a pre-exercise meal was consumed 1–2 hours before training, the window effectively extends across the full inter-meal period.
Confounds in timing studies (total protein differences between conditions) likely account for most of the purported timing effects.

The Schoenfeld et al. (2017) meta-analysis. In a higher-quality test of the question, Schoenfeld, Aragon, and colleagues published a meta-analysis (23 studies, n=525) in PeerJ specifically designed to control for total protein and energy intake when comparing pre- versus post-exercise protein consumption. The result: no statistically significant difference in hypertrophy outcomes (standardised mean difference 0.12, 95% CI −0.06 to 0.29) between pre- and post-workout protein groups when total protein was equated. Timing had a small positive trend, but it was not significant and was attributed largely to residual total-protein differences in individual studies.

Implication for practice. For a patient eating adequate total protein across 4+ meals per day, a post-workout shake or meal within 2–3 hours of training is fine — it does not need to be immediate, and the absence of it will not meaningfully compromise muscle gains. For a patient training fasted (e.g. early morning before breakfast), having a protein source within an hour of training is sensible, as this is the scenario where timing does appear to matter.

Creatine evidence summary. The Kreider et al. (2017) ISSN position stand on creatine (the most comprehensive review in the field, reviewed by 12 international experts) grades creatine monohydrate as the most effective legal ergogenic nutritional supplement currently available for enhancing high-intensity exercise capacity and lean body mass. Key evidence:

Intramuscular phosphocreatine (PCr) resynthesis between high-intensity bursts is the primary mechanism.
3–5 g/day over 28 days achieves muscle saturation without a loading phase.
Benefits accrue across both resistance training (hypertrophy, strength) and high-intensity interval work.
No credible evidence supports renal toxicity in healthy adults at standard doses.
No evidence for benefit from creatine ethyl ester, buffered creatine, or other proprietary forms over monohydrate.

C. Practical supplement and dietary framework

Priority hierarchy for post-workout nutrition. In approximate order of evidence strength and practical impact:

Priority	Element	Evidence grade	Practical target
1	Total daily protein	Level I (multiple meta-analyses)	1.6–2.2 g/kg/day; ≥1.2 g/kg for >65y
2	Protein distribution	Level II–III (RCTs and reviews)	≥0.4 g/kg per meal × 4 meals
3	Leucine content per meal	Level II (mechanistic + clinical)	≥2.5–3 g leucine/meal
4	Creatine monohydrate	Level I (multiple RCTs)	3–5 g/day continuous
5	Post-workout protein timing (fasted only)	Level II (observational + small RCTs)	Within 60 min if 4+ hours since last protein
6	Carbohydrate timing (endurance only)	Level I for endurance; not significant for resistance	0.8–1.2 g/kg/h for 4 h post-session if >90 min cardio
7	Hydration replacement	Level II	150% of sweat loss over 4–6 h

Protein source comparison (per 30 g serving):

Source	Total protein (g)	Leucine (g)	Practical notes
Whey protein isolate	27–29	2.9–3.2	Fast-digesting; highest leucine density
Casein protein	24–26	2.3–2.6	Slow-digesting; useful for overnight MPS
Eggs (4 large)	24	2.1–2.3	Whole food; complete amino acid profile
Skinless chicken breast (120 g)	28–30	2.3–2.5	Versatile; practical post-training meal
Canned tuna (1 can, 185 g drained)	35	~2.8	Cost-effective; convenient
Pea + rice protein blend (40 g)	28–32	2.5–2.8	Best plant-based leucine profile
Soy protein isolate (35 g)	28–30	2.3–2.5	Complete EAA profile among plant proteins

Supplement quality in Australia. The Australian Institute of Sport (AIS) Supplement Framework classifies supplements into Groups A–D by strength of evidence and safety. Group A (strong evidence, safe, appropriate for use) includes: creatine monohydrate, whey protein, casein protein, caffeine, beta-alanine, bicarbonate, beetroot/nitrate. Group B (emerging evidence, use under practitioner guidance) includes: vitamin D, omega-3, collagen/gelatin. Group D (banned or contaminated) — always check products against the WADA 2026 Prohibited List. For 2026, this includes BAM15, flmodafinil, and fladrafinil (which appear in some “pre-workout” supplements). Use only AIS Group A–B products for athletes subject to testing; recommend TGA-registered products or those certified by Informed Sport or HASTA for any competing athlete.

Cost context (Australia, 2026):

Creatine monohydrate: AUD 20–40 per 300 g (approximately 60–100 daily doses at 3–5 g) — roughly AUD 0.20–0.35/day.
Whey protein: AUD 30–60 per 1 kg (approximately 33 servings) — roughly AUD 0.90–1.80/serve.
Both are available at major supermarkets, pharmacy chains, and health food stores without prescription.

D. Australian operations — how to access clinical support

GP-led pathway for muscle mass concerns:

Assess protein intake using a simple food frequency or 24-hour recall at the consultation. Many patients with sarcopenic concerns are eating less than 1.0 g/kg/day.
Check relevant bloods if muscle mass concern is the presenting issue: full blood count (anaemia), CMP (renal function, electrolytes), 25-OH-D (vitamin D), HbA1c (insulin resistance), and testosterone/IGF-1 in men if indicated.
Create a GP management plan (GPCCMP, MBS items 721/723) to enable allied health referrals if ≥2 chronic conditions are co-present.
Refer to an Accredited Practising Dietitian (APD) for complex nutritional assessment (MBS item 10954 — 5 combined allied health visits per calendar year). Find local APDs at dietitiansaustralia.org.au.
Refer to an Accredited Exercise Physiologist (AEP) for resistance training programme (MBS item 10953). An AEP can prescribe and supervise a resistance programme and provide practical nutrition timing advice alongside training.

Telehealth: Dietitian and AEP consultations are available via telehealth under Medicare. For uncomplicated supplementation questions, a GP telehealth consult (MBS item 91790) is appropriate.

E. Special populations

Older adults (≥65 years). Ageing produces “anabolic resistance” — a blunted MPS response to a given protein dose, requiring higher per-meal leucine content to achieve the same response as in younger adults. This means older adults benefit from aiming for the upper end of the 0.4 g/kg/meal target, and from leucine-enriched protein sources or leucine-fortified formulas (e.g. commercial nutritional supplements like Ensure Plus or Sustagen Sport). The PROT-AGE target of ≥1.2–1.6 g/kg/day applies; for frail older adults, a protein intake approaching 1.6 g/kg/day is appropriate. Creatine supplementation also shows benefits in older adults for both muscle and cognitive outcomes, with a strong safety record.

Plant-based athletes. A well-planned plant-based diet can meet protein targets for muscle building, but requires intentional planning. Leucine is the bottleneck — it requires higher serving sizes of plant proteins, careful food combining across the day, and potentially leucine-fortified plant-protein powders (pea + rice blend is the most evidence-supported option). Total protein targets should be set at the higher end (2.0–2.2 g/kg/day) to allow for lower digestibility-corrected amino acid scores (DIAAS) of most plant proteins.

Adolescents (under 18). Sports nutrition principles for adolescents differ from adults in that caloric adequacy and micronutrient density take priority; premature focus on protein optimisation in teens can displace energy-dense, nutrient-dense whole foods. Protein needs in competitive adolescent athletes are approximately 1.4–1.7 g/kg/day — achievable through whole foods without supplementation in most cases. Commercial pre-workout supplements, creatine, and high-dose caffeine are not recommended for under-18s; refer parents and teens to a sports dietitian for any complex query.

People with chronic kidney disease. The 1.6–2.2 g/kg/day target is appropriate for healthy adults with normal renal function. For people with CKD stage 3b or above, higher protein intakes are generally restricted to avoid accumulation of nitrogenous waste. A nephrologist or renal dietitian should guide protein targets in this group; this article does not apply to people with CKD stage 3b+.

When to escalate

Unexplained muscle loss despite adequate protein intake and resistance training — investigate secondary causes (malignancy, endocrine disorder, malabsorption, inflammatory condition).
BMI below 19 with low muscle mass — assess for disordered eating, malnutrition, or underlying catabolic disease.
Adolescent using stacked supplements (pre-workout + creatine + BCAAs + protein) purchased online without professional guidance — screen for WADA-prohibited substances, assess for supplement dependence or disordered eating patterns.
Protein supplement use alongside impaired renal function — refer to nephrology or renal dietetics.
Very-high-protein intake (>3 g/kg/day) without clinical indication — review for eating disorder presentations (orthorexia nervosa, muscle dysmorphia).

What this article is and is not

This article summarises the current evidence on post-exercise protein timing, total protein targets, creatine supplementation, and practical post-workout nutrition for muscle building and recovery in Australian adults. It is intended to support clinical conversations between patients and their GP or treating dietitian; it does not replace an individualised dietary assessment. Supplement recommendations are general; individual athletes subject to anti-doping testing should consult a sports dietitian and verify every product through the HASTA or Informed Sport certification databases before use.

Sources cited

Jäger R, et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20. doi:10.1186/s12970-017-0177-8
Kerksick CM, et al. International Society of Sports Nutrition Position Stand: nutrient timing. J Int Soc Sports Nutr. 2017;14:33. doi:10.1186/s12970-017-0189-4
Kreider RB, et al. International Society of Sports Nutrition Position Stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr. 2017;14:18. doi:10.1186/s12970-017-0173-z
Aragon AA, Schoenfeld BJ. Nutrient timing revisited: is there a post-exercise anabolic window? J Int Soc Sports Nutr. 2013;10(1):5. doi:10.1186/1550-2783-10-5
Schoenfeld BJ, Aragon A, Wilborn C, Urbina SL, Hayward SE, Krieger J. Pre- versus post-exercise protein intake has similar effects on muscular adaptations. PeerJ. 2017;5:e2825. doi:10.7717/peerj.2825
Morton RW, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376–384. doi:10.1136/bjsports-2017-097608
Bauer J, et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. J Am Med Dir Assoc. 2013;14(8):542–559. doi:10.1016/j.jamda.2013.05.021
Australian Institute of Sport. AIS Sports Supplement Framework. 2024. ais.gov.au
Sports Dietitians Australia. Protein for sports and exercise. 2023. sportsdietitians.com.au
HealthDirect. Protein and exercise. Australian Government, 2024. healthdirect.gov.au

Frequently asked questions

Do I need to eat immediately after training or the gains are lost?

No. The 'anabolic window' — the idea that muscles are uniquely receptive to protein only in the 30–60 minutes after a workout — was derived from studies comparing fed versus fasted training conditions, not well-nourished participants eating at different time points. Aragon and Schoenfeld (2013) reviewed the literature and concluded that the post-exercise window is far wider than popular belief suggests, and Schoenfeld's 2017 PeerJ meta-analysis confirmed that when total protein is equated, training proximity adds no significant advantage. If you trained without eating for 4+ hours beforehand, eating within an hour post-session makes sense. If you had a protein-containing meal 1–2 hours before training, total daily intake matters far more than the post-workout clock.
How much protein do I need per day for muscle building?

For most resistance-training adults, 1.6–2.2 g per kilogram of bodyweight per day represents the evidence-supported range for maximising muscle protein synthesis responses (Morton 2018 BJSM meta-analysis; ISSN 2017 Jäger position stand). Going above 2.2 g/kg provides no additional benefit for muscle gain but is not harmful in healthy adults with normal kidney function. For a 75 kg person, this is approximately 120–165 g per day. Distributing this across 4 meals of 30–40 g each, rather than consuming most in one sitting, is supported by evidence on leucine thresholds and MPS stimulation. Higher-quality proteins (whey, casein, eggs, chicken) generally provide a higher leucine content per gram of protein, which matters for MPS activation.
What is the leucine threshold and why does it matter?

Leucine is the amino acid that acts as the primary trigger for mTOR/mTORC1 activation — the anabolic signalling pathway that drives muscle protein synthesis (MPS). Research suggests that approximately 2.5–3 g of leucine per serving is required to maximally activate MPS. A standard 25 g serving of whey protein provides roughly 2.7–3 g of leucine, which is why 25–30 g of high-quality protein per meal is the commonly cited threshold. Plant-based proteins typically have lower leucine concentrations per gram of total protein (e.g. soy ~8% leucine vs whey ~10–11%), which is why plant-protein servings often need to be 30–40 g to achieve the same leucine dose. Combining complementary plant proteins (rice + pea, soy + wheat) addresses both leucine and methionine/lysine balancing.
Should I take creatine and when?

Creatine monohydrate is the most extensively researched ergogenic supplement and is classified as a Group A (performance-enhancing with strong evidence) supplement by the Australian Institute of Sport. The standard approach is 3–5 g per day continuously — no loading phase is needed. A loading phase (20 g/day in 4 divided doses for 5–7 days) reaches saturation about 3 weeks earlier than gradual loading but adds no long-term benefit. Creatine timing (pre vs post workout) does not appear to matter meaningfully; the key is daily consistency. In 2026, creatine monohydrate powder costs approximately AUD 20–40 for 300 g in Australia — roughly AUD 0.20–0.35 per daily dose, making it among the most cost-effective supplements with strong supporting evidence.
Do carbohydrate timing rules apply to resistance training?

For most resistance-training adults doing 3–5 sessions per week, carbohydrate timing after exercise has minimal independent effect on muscle outcomes. What matters is meeting daily carbohydrate targets for energy and glycogen replenishment overall. The exception is endurance athletes or those training twice daily: in these athletes, rapid glycogen resynthesis (0.8–1.2 g/kg/hour of carbohydrate for the first 4 hours post-exercise, ideally combined with protein) is clinically relevant because inadequate glycogen before the next session impairs performance. For a person doing a standard 60-minute resistance session, eating a carbohydrate-containing meal within a few hours post-training (not necessarily immediately) is entirely adequate.

Source quality

Sources grouped by evidence tier. AU primary tier first; international where AU is silent or lagging; named-author reconstruction where guidelines have not yet caught up. How tiers work.