What should I eat before a long run?

One to two grams of carbohydrate per kilogram of bodyweight, two to three hours before, with fat and fibre kept low so it clears. For a 180 lb athlete that is roughly 80 to 160 grams. Under 60 minutes of work glycogen is not the limiter and you can train fasted at no cost.

Do I need to eat during a long session?

Over about 90 minutes, yes. Thirty to sixty grams of carbohydrate per hour is the well-supported range, rising toward 90 grams for efforts over two and a half hours if you use a glucose-fructose mix and have trained your gut for it. Under 90 minutes, water is usually enough.

Does fasted cardio burn more fat?

It oxidises more fat during the session and produces no advantage in fat loss over 24 hours, because total energy balance decides that and it does not care when the fat was oxidised. What fasted training does reliably do is lower the quality of the session and raise its recovery cost.

Why is my lifting bad after a long run?

Usually glycogen rather than fatigue. A depleted long session takes 24 to 48 hours to refill muscle glycogen even with adequate carbohydrate, and a heavy session on partly refilled glycogen feels like weakness. Under-fuelling the run is the most common cause and the least often diagnosed.

How much carbohydrate after a long session?

About 1 to 1.2 grams per kilogram per hour for the first four hours if you are training again within 24 hours. If the next session is more than a day away, total daily intake matters far more than the timing and you can simply eat normally.

Fuelling Long Sessions Without Wrecking Your Lifting

The threshold that matters

Session length	Glycogen the limiter?	Fuelling needed
Under 60 min	No	None. Fasted is fine
60–90 min	Marginally	Pre-session carbohydrate helps at the top end
90–150 min	Yes	Pre-session plus 30–60 g/hour during
Over 150 min	Emphatically	Pre-session plus 60–90 g/hour, glucose-fructose mix

Muscle glycogen stores hold roughly 400 to 500 grams for a trained athlete, which is about 1,600 to 2,000 kcal. At a moderate endurance intensity you are drawing several hundred grams per hour of work from a mix of glycogen and fat, so the tank is genuinely finite and the arithmetic is not close at three hours.

Before

1 to 2 g/kg of carbohydrate, two to three hours out. For a 180 lb (81.6 kg) athlete: 80 to 160 grams.

Keep fat and fibre low. Both slow gastric emptying, and a meal that has not cleared by the time you start is a meal that becomes a problem at mile four rather than an advantage.

If the session is early and a three-hour lead time is not available, a smaller carbohydrate-only feed 30 to 60 minutes before is better than nothing — 30 to 50 grams of something simple.

During

Over ninety minutes: 30 to 60 g of carbohydrate per hour.

Over two and a half hours, and if you have trained your gut for it, up to 90 g/hour is achievable with a glucose–fructose mix. The reason for the mix is mechanical: glucose absorption saturates at roughly 60 g/hour because it depends on one transporter, and fructose uses a different one. Combining them raises the ceiling that a single sugar cannot pass.

"Trained your gut for it" is not a figure of speech. Tolerance for high carbohydrate intake during exercise is itself trainable and takes weeks. Attempting 90 g/hour for the first time on race day is a well-documented way to have a bad race.

After

If you are training again within 24 hours: 1 to 1.2 g/kg per hour for the first four hours.

If the next session is more than a day away, timing stops mattering much and total daily intake takes over. The "anabolic window" for carbohydrate is real but narrow in application — it matters when the refill has to happen fast, and not otherwise.

Protein alongside it, 30 to 40 g. Not because it accelerates glycogen resynthesis meaningfully when carbohydrate is adequate, but because you were going to eat it anyway and this is a convenient time.

Why the bill arrives on Monday

This is the part specific to hybrid athletes and the reason this page exists.

A depleted Saturday long run leaves muscle glycogen low. With adequate carbohydrate intake, full resynthesis takes 24 to 48 hours. With inadequate intake — which is what happens when the long run was not counted in the calorie target — it takes longer.

Monday's heavy lower-body session then happens on a substrate deficit. What that feels like from the inside:

The warm-up weights feel heavier than they should
Reps that should be RIR 2 come out at RIR 0
The last set is a grind at a load you handled comfortably last week
You conclude your recovery is poor, or the block is too aggressive, or interference is real

The actual cause is a Saturday nutrition decision. Nothing about Monday was wrong.

This is also why a fixed daily calorie target fails hybrid athletes so specifically. Saturday costs 1,500 more calories than Wednesday. A target that cannot see the difference under-feeds Saturday, and the cost surfaces on Monday where nobody is looking for it. How the daily target moves with the day.

Fasted training, honestly

Fasted endurance work oxidises more fat during the session. It produces no advantage in fat loss over 24 hours, because total energy balance decides that and it does not care when in the day the fat was oxidised.

What fasted work does reliably do:

Lower the quality of the session, at any intensity above easy
Raise its recovery cost
For a hybrid athlete, extend the glycogen deficit into the next lifting session

There is a legitimate case for occasional low-carbohydrate-availability training in endurance-primary athletes, aimed at specific metabolic adaptations. It is a targeted tool used in specific blocks, and it is a poor default. For an athlete also trying to build or hold muscle it is a poor tool full stop, because the cost lands on the half you were trying to protect.

Under sixty minutes and easy, none of this applies. Train fasted if you prefer to.

Practical numbers for a 180 lb athlete

Session	Before	During	After
45 min easy run	Nothing needed	Water	Normal meals
75 min tempo	60–80 g carbohydrate, 2 h out	Water	Normal meals
2 h long run	100–160 g, 2–3 h out	40–60 g/hour	80–100 g/hour for 4 h if training tomorrow
3 h ride	130–160 g, 3 h out	60–90 g/hour, glucose–fructose	80–100 g/hour for 4 h
Two-a-day	Full meal before the first	Per session above	1–1.5 g/kg between sessions

Common mistakes

Fasting a long run by default. Fine under an hour; expensive over ninety minutes.
Attempting 90 g/hour untrained. Gut tolerance takes weeks to build.
High fat or high fibre in the pre-session meal. It will not clear.
Not eating between two sessions on the same day. Turns the second into a depleted session.
Blaming Monday's lift on Monday. Look at Saturday.
Treating the post-session window as urgent when the next session is two days away. It is not.

What to do next

Take your longest session of the week and check what you ate in the three hours before it and during it against the table above. If the answer is "not much", you have probably found the reason your first lifting session after it has been going badly.