How to use the Nutrition Planner
Nutrition Planner plans fuelling and hydration for races and long sessions: carbohydrate, sodium and fluid targets, which gels, chews and drink mixes to carry, and how to mix each bottle.
How to use it
- Targets: set the duration (or calculate it from distance and pace, or from a planned Intervals.icu workout) and your carbs, sodium and fluid per hour. The Carb Calculator suggests sport-specific carb rates and glucose:fructose ratios, and the Sweat Loss Calculator estimates sodium needs from sweat rate and sweat sodium.
- Ingredients: add products from the search or browse list. Mark each as Auto (the planner works out how much) or Fixed, and as a Drink or Other.
- Outputs: check totals, per-hour and per-bottle values, and any flags.
- Recipe: the final quantities to mix and pack, ready to print.
- Log: optionally send what you planned or ate to custom fields in Intervals.icu.
Segmented mode gives each leg of a race its own targets and ingredients, for example between ultra aid stations, or for the swim, bike and run of a triathlon. Quick Log skips the planning: you log a couple of gels after a training run in a few taps.
How it works: carbohydrate
The carb presets follow the multiple transportable carbohydrate model. Glucose and maltodextrin are absorbed from the gut by the SGLT1 transporter, and fructose by a different transporter, GLUT5. The glucose route saturates at roughly 60 g per hour, so taking glucose and fructose together lets more carbohydrate be absorbed and used than glucose alone (Jentjens & Jeukendrup, 2005), and improved endurance performance compared with glucose alone (Currell & Jeukendrup, 2008).
- Up to about 90 g/h the exact ratio matters less, and close blends such as 1:0.8 work well.
- At 120 g/h, a 1:0.8 fructose:maltodextrin blend raised the amount of ingested carbohydrate used compared with 90 g/h in a 1:2 ratio (Podlogar et al., 2022). At 120 g/h, drinks, gels, chews and combinations of them were used about equally well (Hearris et al., 2022).
- Ingested carbohydrate is used about as well during running as during cycling (Pfeiffer et al., 2011). Gut symptoms, though, were more common during running than during cycling in a controlled comparison: 44% of athletes against 25%, although they were no more severe (Costa et al., 2022). So the running presets are more conservative and top out at 120 g/h. Cycling also has 150 g/h (advanced) and 180 g/h (experimental) tiers, meant for athletes who have trained their gut to tolerate them (Jeukendrup, 2017).
How it works: hydration and flags
The planner flags values outside general guideline ranges so you can fine-tune them. These are reference points, not rules, and plenty of athletes deliberately plan outside them:
| Flag | Shown when |
|---|---|
| Carbs, sodium | Totals differ from duration × your hourly target |
| Ratio | Actual glucose:fructose differs from your target |
| Hydration | Total fluid outside 500–1000 mL per hour |
| Carb concentration | Drink above 8% (8 g per 100 mL) |
| Sodium concentration | Drink outside 400–1100 mg per litre |
| Osmolarity | Drink below 270 or above 330 mOsm/L, roughly the range of blood. Above 450 mOsm/L the drink is likely to cause gut trouble unless diluted. |
Calories use the 4/4/9 rule (4 kcal per gram of carbohydrate and protein, 9 per gram of fat). Caffeine is also shown in mg per kg of body weight.
Related
References
- Currell K, Jeukendrup AE. Superior endurance performance with ingestion of multiple transportable carbohydrates. Med Sci Sports Exerc. 2008. PubMed
- Jentjens RL, Jeukendrup AE. High rates of exogenous carbohydrate oxidation from a mixture of glucose and fructose ingested during prolonged cycling exercise. Br J Nutr. 2005. PubMed
- Podlogar T, Bokal Š, Cirnski S, Wallis GA. Increased exogenous but unaltered endogenous carbohydrate oxidation with combined fructose-maltodextrin ingested at 120 g/h versus 90 g/h at different ratios. Eur J Appl Physiol. 2022. PubMed
- Hearris MA, et al. 13C-glucose-fructose labeling reveals comparable exogenous CHO oxidation during exercise when consuming 120 g/h in fluid, gel, jelly chew, or coingestion. J Appl Physiol. 2022. PubMed
- Pfeiffer B, et al. Carbohydrate oxidation from a drink during running compared with cycling exercise. Med Sci Sports Exerc. 2011. PubMed
- Jeukendrup AE. Training the gut for athletes. Sports Med. 2017. PubMed
- Fuchs CJ, et al. Fructose co-ingestion to increase carbohydrate availability in athletes. J Physiol. 2019. PubMed
- Costa RJS, et al. The impact of exercise modality on exercise-induced gastrointestinal syndrome and associated gastrointestinal symptoms. J Sci Med Sport. 2022. PubMed
RunTK's tools are for planning and education. They aren't medical advice, and the right numbers for you depend on your health, experience and goals.
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