SYNTH-85 · Guide
Fuelling for tomorrow
When the next hard session is close (a same-day double, back-to-back hard days, a stage race or a camp): fuel the first session at the top of its rehearsed row, eat fast carbohydrate with some fructose as soon as it ends, and cover the day's load in g/kg; very high on-bike intakes are a recovery tool with thin evidence, not a way to refill tomorrow's muscles
Default (what to prescribe first)
1
Name the gap first (gap bands: practice). Under ~6 h, timing and type matter; around 24 h, the day's total matters; 48 h or more is an ordinary day (SYNTH-69). With 2 h of delay, glycogen was stored at a third of the rate of eating straight away (REF-056, B); the entry's own inference is that with 24 h and adequate intake it catches up.
2
3
Decision (gap → what changes)
| Next hard session | During the first session | Straight after | The rest of the day | Source and how sure |
|---|---|---|---|---|
| Same day, under ~6 h (4 h tested) | Its SYNTH-02 row; start it fed | 1-1.2 g/kg/h through the gap, fast carbohydrate, ~40% fructose-containing (fruit, juice, honey, sucrose); 0.3-0.4 g/kg protein | — | REF-748 A (dose); REF-056 B (now, not in 2 h: 7.7 vs 2.5 µmol/g/h); REF-734 B+ (fructose + maltodextrin at 90 g/h: second run 81.4 vs 61.4 min, n=8, treadmill running); REF-064 B (liver glycogen 8.1 vs 3.7 g/h); gap band is practice |
| Next day (~24 h) | Top of the rehearsed SYNTH-02 row; in elite trail runners only 120 g/h avoided a 24-h drop in jump and half-squat | Carbohydrate early; fast sources for the recovery meals | The day's load in g/kg — the total is the lever | REF-332 B+, REF-331 B+ (lower CK, LDH, GOT at 24 h with 120 g/h); REF-057 B (high- vs low-GI over 24 h: 106 vs 71.5 mmol/kg); REF-748 A |
| Consecutive hard days (stage race, camp) | 90-120 g/h if rehearsed (SYNTH-02 multi-day row, practice) | As above, every day | Professionals: >8 g/kg on days over 4 h, 10-25 g/kg in >6-h races and stage events, 7,000-9,000 kcal days — an amateur scales by hours (practice; the consensus calls amateur translation an open question) | REF-748 A (written for elite riders); REF-334 C+ (the plausible case for ≥100 g/h is recovery across days); daily monitoring: REF-755 C+ |
| 48 h or more | Its SYNTH-02 row | Normal meal | SYNTH-69 | — |
What extra on-bike carbohydrate does — and does not — do
But not more carbohydrate in total above 120 g/h: whole-body carbohydrate oxidation was 2.6 g/min at both 120 and 150 g/h (REF-1103). Arithmetic on those numbers: the extra 0.14 g/min from the drink replaced about 25 g of the athlete's own carbohydrate over 3 h — one recovery snack.
Which store is spared: the authors of the proposed 120 g/h ceiling frame the benefit as sparing liver "and potentially muscle" glycogen (REF-3490); 60 g/h held critical power over 2 h without a detectable change in muscle glycogen depletion (REF-145, B+); an argued review holds that carbohydrate during exercise reduces liver glycogen breakdown and may even speed muscle glycogen use (REF-476, B+, contested); pooled crossovers point the other way on muscle, a small sparing (SMD −0.16, ~24 mmol/kg dry weight over ~110 min) with ingestion rate not a significant moderator (REF-1123, B+).Maltodextrin + fructose rebuilt liver glycogen after exercise about twice as fast as maltodextrin + glucose (8.1 vs 3.7 g/h, REF-064).
So "eat more on the bike to refill tomorrow's muscles" is not shown. The next-day benefit of 120 g/h in REF-331 and REF-332 went with lower damage markers and internal load; that glycogen explains it is inference. Running damages muscle far more than cycling (3 days × 2.5 h: 133% more CK in runners, REF-235, B+), so a damage-mediated benefit may be smaller on the bike (inference).
Protein does not replace carbohydrate: added to adequate carbohydrate it brought no performance or glycogen benefit (REF-151); it serves the day's total.
Practical Application
Same-day double: recovery carbohydrate in the first 15-30 minutes (practice), fast and partly fructose — rice, bread, potatoes, ripe fruit, juice, honey, a sugared drink, milk. Real food counts (REF-734's own application).
Stage race or camp: the day's carbohydrate rises with the hours, and higher RPE at the same heart rate, or not reaching the usual top heart rate, marks overreaching (REF-755, C+, six professional women); reading it, or a weight drop, as under-fuelling is practice.
Alcohol: the recovery meal first and in full (REF-1013, B).
Caffeine with recovery carbohydrate raised resynthesis in one study at a very high dose, the only one tested (8 mg/kg; REF-059, B) — not a default.
Limitations
Recovery trials are small (5-12 trained participants, mostly men; sex not reported in REF-734, REF-059, REF-1013) and short (4-24 h); no data in women.
The next-day benefit of on-bike intake comes from two trials in elite trail runners; no cycling stage-race trial compares on-bike doses against next-day performance.
The professional daily bands describe Grand Tours; the amateur scaling and the gap bands are practice.
Liver versus muscle sparing during exercise is disputed between the cited reviews; pooled crossovers find only a small muscle sparing with no detected dose effect (REF-1123).
Revision 2026-10-13: folded REF-1123 (Rothschild 2026, full text).
How this entry was checked and changed
Why this level
(recovery doses on an A consensus written for professional cycling; timing, glycaemic index and fructose on B/B+ crossovers of 5-12 trained participants, mostly men; the next-day benefit of on-bike intake on two B+ trials in elite trail runners; the mechanism on B/B+ studies and reviews that disagree; the gap bands are practice)