Pre- and post-workout nutrition: what actually matters

An evidence-based, deliberately de-hyped guide to eating around training. The supplement industry has built a mythology around "nutrient timing" — the pre-workout stack, the fasted-cardio hack, the frantic dash to a protein shake before the "anabolic window" slams shut. Most of it doesn't survive contact with the research. This covers what genuinely helps: carbohydrate before longer or harder sessions, whether to train fasted, when fuelling during a workout actually matters, how much protein afterwards, the real width of the anabolic window, and the one situation where racing to refuel truly counts.

Here's the honest version in a sentence: for most people, what and when you eat right around a workout matters far less than hitting enough total protein and carbohydrate across the whole day — a carbohydrate top-up before longer or harder sessions helps, the "anabolic window" is hours wide rather than minutes, and rushing to eat the moment you finish only genuinely matters when you have to refuel for another hard session the same day. Everything below is the detail behind that, with the numbers traced to published sports-nutrition consensus.

A framing note before the numbers. Sports nutrition is well studied, but people differ enormously — body size, training type and intensity, goals, schedule, gut tolerance and health status all shift what's right on the day. So this is written as can, tends to and around, never as a guarantee, and every specific figure is a population-level guide drawn from published consensus, not a personal prescription. It's general education, not medical or dietary advice, and it isn't a personalised plan.

The big picture: the day beats the window

Before any single meal, one idea should reframe the whole topic: your total daily intake of protein, carbohydrate and energy does far more for your results than the precise timing of any one feed around a workout. This isn't a fringe opinion — it's the explicit conclusion of the International Society of Sports Nutrition's position stands, which state that meeting your total daily protein, in evenly spaced feedings, "should be viewed as a primary area of emphasis," and that when researchers pool the studies, the timing of nutrients "does not necessarily trump other feeding strategies."

That's liberating, because it means you don't have to get the timing perfect to get results. If your total daily protein and carbohydrate are on point and reasonably spread out, you've already captured the large majority of the benefit. Timing is the fine-tuning on top — useful in specific situations (long endurance sessions, twice-a-day training, competition), and largely optional for the everyday gym-goer. Keep that hierarchy in mind as we go section by section: the "before", "during" and "after" details below are the icing, and the daily total is the cake.

Before you train — carbohydrate and the fasted question

Two things can help before a session: arriving with reasonably full glycogen (your muscles' stored carbohydrate), and not being so hungry that the session suffers. For an easy or short workout, neither is usually a problem, and you can often train on an empty stomach with no real downside. Before longer or harder sessions, a carbohydrate-focused top-up helps you perform.

The published guidance is specific. Position stands describe a pre-exercise meal or snack of roughly 1–4 g of carbohydrate per kilogram of body weight, eaten around one to four hours beforehand, with the larger amounts taken earlier (when there's time to digest) and smaller amounts closer to the start. The ISSN frames this as loading carbohydrate "for several hours before higher-intensity, longer-duration exercise." Favour familiar, lower-fibre, lower-fat carbohydrate you've tested before — porridge, toast, a banana, rice — because fibre and fat slow digestion and can sit heavily. A little protein alongside is fine and, before resistance training, can double as one of your daily protein doses.

What about training fasted? It's become a fitness identity, so it's worth being blunt: for body composition, fasted training is not a shortcut. A systematic review with meta-analysis found that fasted and fed resistance training produce similar changes in muscle mass, strength and body fat, and a randomised trial of twelve weeks of fasted lifting reported the same hypertrophy and strength gains as training fed. For "fasted cardio" specifically, a controlled comparison found no meaningful body-composition difference between fasted and fed aerobic exercise once total daily calories were matched. Fat loss is governed by your energy balance across days, not by whether one session happened before breakfast.

So the fasted question comes down to preference and performance, not fat-burning magic. If you like training first thing on an empty stomach and it feels fine, carry on. If you're doing a long or genuinely hard session, eating some carbohydrate beforehand tends to help you train better — and training better, session after session, is what actually drives results.

During — when mid-session fuelling matters

Here the honest answer disappoints the supplement aisle: for most workouts, you don't need to eat anything mid-session at all. Your stored glycogen comfortably covers efforts up to roughly 60–90 minutes, so intra-workout carbohydrate does little for a typical gym session or a short-to-moderate run. The ISSN notes that the benefit of carbohydrate during bouts shorter than about 70 minutes is "largely mixed" — a polite way of saying it usually isn't needed.

There is one neat exception at the short end. For hard efforts of roughly 30–75 minutes, simply rinsing your mouth with a carbohydrate drink and spitting it out can give a small performance boost — on the order of a few percent — not by fuelling the muscle but by signalling reward centres in the brain through receptors in the mouth. It's a curiosity worth knowing, not a daily necessity.

Once a session genuinely runs long, fuelling starts to earn its keep. The picture scales with duration:

Those upper numbers — 30–60 g per hour for multi-hour efforts, rising toward 90 g per hour for very long endurance events using a glucose–fructose blend — are the domain of distance runners, cyclists and triathletes, not the average lifter. If that's your world, the sport-specific fuelling guides go deep on it; see the running fuelling guide for the full during-exercise ladder and the gut-training that makes those intakes tolerable. For everyone doing a normal 45-to-90-minute workout, the practical takeaway is simpler: water is usually all you need to carry.

After — protein and the "anabolic window"

This is the part with the most mythology, so let's take it apart carefully. Resistance training temporarily raises your muscles' sensitivity to protein — feed them amino acids and they build. The old story was that this window slams shut about 30 minutes after your last rep, so you had to gulp a shake immediately or "waste" the session. That story is wrong.

The evidence is clear that the window is hours, not minutes. Muscle remains sensitised to protein for at least 24 hours after a resistance session, and muscle protein synthesis stays elevated for a day or more. The researchers who literally wrote the review titled "Is there a post-exercise anabolic window?" concluded the practical window is wide — on the order of four to six hours bracketing the workout, and plausibly longer, depending on when and what you last ate. And when the studies on protein timing are pooled, a meta-analysis found only a small apparent effect of timing — one that essentially vanished once you accounted for the fact that the "timing" groups simply ate more total protein. In other words, the benefit attributed to timing was mostly the benefit of eating enough protein.

So what should you actually do after training? Have a normal protein-containing meal within a few hours — which, for most people eating three or four times a day, happens without any effort at all. The useful number is the dose: roughly 0.25–0.40 g of protein per kilogram of body weight per meal (about 20–40 g for most people) maximally stimulates muscle protein synthesis in one sitting; piling much more into a single feed doesn't add proportionally more for muscle building. Across the whole day, position stands recommend around 1.4–2.0 g of protein per kilogram for people training to build or keep muscle, spread over three or four evenly spaced meals roughly every three to four hours. The post-workout meal is simply one of those doses — a good habit, but not a magic one.

One nuance for people who train fasted and haven't eaten for many hours: here the pre/post distinction matters a little more, because you want a protein feed reasonably close to the session on either side rather than leaving a very long gap around it. Even then, "reasonably close" means within a few hours, not sixty seconds. If you ate a protein-containing meal an hour or two before lifting, that food is still being digested and released during and after your workout, which further softens any urgency to eat the instant you finish.

After — refuelling glycogen (and when to rush)

Carbohydrate after training is where a genuine "window" does exist — but only for a specific person in a specific situation. The job here is refilling the glycogen you burned, and how fast you need to refill it depends entirely on when you'll train hard again.

• Fast turnaround (another hard session within a few hours, or twice-a-day training). Speed matters. Research on rapid recovery describes taking in carbohydrate at around 1.0–1.2 g per kilogram of body weight per hour in the first few hours after exercise — favouring higher-glycaemic sources — to restock glycogen as quickly as possible, because the muscle is most receptive soon after you stop. Adding some protein (roughly 0.25–0.3 g/kg) supports repair and appears to help glycogen refilling most when you can't get quite enough carbohydrate in. This is the scenario — an endurance athlete or a two-a-day trainee with only hours to recover — where "eat straight after" is real advice.
• Normal turnaround (a full day or more until the next hard session). There's no need to rush at all, and this covers most gym-goers. Simply hitting your usual daily carbohydrate across normal meals refills glycogen comfortably well before you need it. The urgency evaporates when the recovery window is long — which, for the typical three-or-four-times-a-week trainee, it almost always is.

So the "carb up immediately after" advice isn't wrong — it's just narrowly scoped. It was distilled from studies on athletes doing glycogen-depleting work with tight turnarounds, then over-generalised into a rule for everyone. If your next hard session is tomorrow, tonight's normal dinner does the job.

Putting it together

Strip away the hype and peri-workout nutrition collapses into a short, practical checklist:

• Get your daily totals first. Enough protein (about 1.4–2.0 g/kg/day if you're training to build or keep muscle), enough carbohydrate for your training load, and appropriate overall energy for your goal. This is 80 % of the game.
• Before longer or harder sessions, have a familiar carbohydrate-focused meal or snack (~1–4 g/kg, one to four hours ahead). For short or easy sessions, eat if you want to — fasted is fine, and it's no fat-loss shortcut.
• During, most workouts need nothing but water. Fuel only when the effort runs past ~60–90 minutes (~30–60 g carbs/hour, up to ~90 g/h for very long endurance events).
• After, have a normal meal with ~20–40 g (0.25–0.40 g/kg) of protein within a few hours — no dash required, because the window is hours wide. Only rush carbohydrate (~1.0–1.2 g/kg/h) if another hard session is coming the same day.

That's genuinely it. The rituals sold as essential — the precisely-timed pre-workout, the immediate post-workout shake, fasted cardio for fat loss — are mostly optional flourishes on top of the two things that carry the load: eat enough, and spread your protein across the day.

Common questions

Do I need to eat before I train?

Not always. For an easy or short session — under about an hour — you can often train fasted with no real downside: controlled trials find fasted and fed resistance training produce similar gains in muscle and strength, and fasted versus fed cardio shows no meaningful body-composition advantage either way. Before longer or harder sessions, though, a carbohydrate-focused meal or snack helps performance. Sports-nutrition position stands describe roughly 1–4 g of carbohydrate per kilogram of body weight, eaten around one to four hours beforehand — larger and earlier, or smaller and closer to the start, based on what your stomach tolerates. If you train first thing and dislike eating early, a small, familiar snack is usually enough.

Is the "anabolic window" real — do I have to eat protein within 30 minutes of training?

The narrow 30-minute window is largely a myth. Resistance exercise leaves muscle sensitised to protein for at least 24 hours afterwards, and muscle protein synthesis stays elevated for a day or more, so there is no need to sprint to a shaker. Reviews put the practical "window" at several hours around the session — roughly the four to six hours bracketing your workout — not minutes. What matters far more is hitting your total protein for the day, spread across meals. The one real exception is fast glycogen refuelling for endurance athletes who have another hard session only a few hours away.

How much protein should I have after a workout?

A per-meal dose of roughly 0.25–0.40 g of protein per kilogram of body weight — about 20–40 g for most people — is enough to maximally stimulate muscle protein synthesis in one sitting; much more in a single hit does little extra for muscle building. Across the whole day, position stands suggest around 1.4–2.0 g of protein per kilogram for people training to build or keep muscle, spread over three or four evenly spaced meals. The post-workout meal is simply one of those doses, not a magic one.

Do I need to fuel during my workout?

Usually only if it runs long. For sessions under about 60–90 minutes, your existing muscle glycogen covers the work and eating during it adds little; for very hard but shorter efforts, even a carbohydrate mouth rinse — swilled and spat — can give a small edge through the brain rather than the gut. Once you push past roughly 60–90 minutes of continuous effort, taking in around 30–60 g of carbohydrate per hour helps maintain blood glucose and delay fatigue, rising toward about 90 g per hour (using a glucose–fructose mix) for very long endurance events beyond about two-and-a-half to three hours.

Should I eat carbohydrate after training to refuel?

It depends how soon you will train hard again. If another tough session is only a few hours away, refuel aggressively: research on rapid recovery describes around 1.0–1.2 g of carbohydrate per kilogram of body weight per hour, from higher-glycaemic sources, in the first few hours to refill glycogen fast, with some protein alongside. If you have a full day or more before the next hard session — which covers most gym-goers — there is no need to rush; hitting your normal daily carbohydrate across regular meals refills stores comfortably in time.

Can I train fasted to burn more fat?

You can train fasted, but it is not a shortcut to fat loss. Fasted and fed cardio produce similar body-composition changes when total daily calories match, and fasted resistance training yields similar muscle and strength gains to training fed. Fat loss is driven by your overall energy balance across days, not by whether one session happened on an empty stomach. Fasted training is a personal-preference and convenience tool — fine if you like it, unnecessary if you don't — and for long or high-intensity sessions, eating beforehand tends to help you perform better.

Takeaways

• The day beats the window. Total daily protein, carbohydrate and energy matter far more than the precise timing of any one meal around training.
• Before: a familiar carb-focused meal (~1–4 g/kg, one to four hours ahead) helps longer or harder sessions; fasted is fine for short/easy ones and is no fat-loss hack.
• During: most workouts need only water. Fuel (~30–60 g carbs/hour) once past ~60–90 minutes; up to ~90 g/h for very long endurance events.
• The anabolic window is hours, not minutes. Muscle stays sensitised to protein for at least 24 hours; there's no need to race to a shaker.
• After (protein): ~0.25–0.40 g/kg (about 20–40 g) per meal, as part of ~1.4–2.0 g/kg/day spread over three or four feeds.
• After (carbs): only rush refuelling (~1.0–1.2 g/kg/h) if another hard session is the same day; otherwise normal meals refill glycogen in plenty of time.
• Ignore the rituals sold as essential. Eat enough and spread your protein across the day, and you've captured almost all of what nutrient timing can offer.

If you remember one thing, make it this: nutrient timing is real but second-order. Nail your daily protein, carbohydrate and energy, add a carb top-up before the long or hard stuff, and eat a normal protein-containing meal within a few hours afterwards — and you've done everything the evidence actually rewards. Strathlon's job is to keep those daily totals honest by adjusting your targets around the sessions you log, so the part that matters is one less thing to guess at.

This is general educational information, not medical, dietary or coaching advice. The sports-nutrition figures here are drawn from established consensus (including the International Society of Sports Nutrition position stands and the joint position of the Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine) and are framed as population-level guides — individual needs vary widely with body size, training, goals, gut tolerance and health, and are best personalised with a qualified professional. Anyone with a health condition, a history of disordered eating, or who is pregnant or postpartum should consult a physician or registered dietitian before making changes. See our Terms for more.

← All guides · How muscle actually grows · How much protein you need · Eating for results · Fuelling for running · Home