How should you fuel for Ironman 70.3 South Africa?
For an Ironman 70.3 in South Africa, take most of your carbohydrate on the bike at 60 to 90 g an hour, with fluid to thirst and sodium if you sweat heavily, then 30 to 60 g an hour on the run. Eat a carbohydrate-rich breakfast two to three hours before and use caffeine late. Practise the whole plan in training.
- An Ironman 70.3 (1.9 km swim, 90 km bike, 21.1 km run) takes most finishers about four to eight and a half hours, so 60 to 90 g/h of carbohydrate on the bike is supported (Jeukendrup 2014).
- Aim for 30 to 60 g/h on the run, where the gut tolerates less.
- Fuelling 300 g of carbohydrate costs roughly R175 with 32Gi Race drink, R300 with Biogen Elite gels and R900 with Maurten Gel 100 (October 2026, our calculation).
- ISSN caffeine dose is 3 to 6 mg/kg; use a late top-up and test it in training.
What does a 70.3 demand?
An Ironman 70.3 is a 1.9 km swim, a 90 km bike and a 21.1 km run. Most finishers take roughly four to eight and a half hours, which puts the event in the "over 2.5 hours" fuelling zone. South African race days add heat, humidity on the coast and often wind.
What is the carbohydrate plan?
Jeukendrup's framework supports up to 90 g/h beyond 2.5 hours with glucose and fructose, and 60 g/h for 2 to 3 hours. The gut copes best on the bike (seated, steady), so load there and ease off on the run.
| Leg | Typical time | Carbohydrate | Fluid |
|---|---|---|---|
| Swim | 30 to 50 min | none; eat before | none |
| Bike | 2.5 to 4 h | 60 to 90 g/h | drink to thirst, add sodium if salty |
| Run | 1.75 to 3 h | 30 to 60 g/h | sips at aid stations |
For a 5.5-hour finisher: about 210 g on the bike (75 g/h for 2.8 h) and 90 g on the run, roughly 300 g in total. Cost at October 2026 prices, using our cost per gram: 32Gi Race drink about R175, Biogen Elite Carb Gel about R300, SiS GO about R610, Maurten Gel 100 about R900. A common pattern is a carb drink in bottles on the bike and gels on the run. See best carb drink for cycling.
How much should you drink?
Sweat rates of 0.5 to 2 L/h are common, so run a sweat test on long bricks. Drink to thirst; overdrinking is the main cause of hyponatraemia, and slower athletes beyond four hours are at highest risk. Weigh in on rides: gaining weight signals too much fluid. See what is hyponatraemia. Electrolyte sachets cost about R4.63 to R25 per serving (October 2026); read the sodium on the pack.
When should you use caffeine?
ISSN supports 3 to 6 mg/kg. A common approach is a smaller pre-race dose, then a top-up late on the bike or early in the run. Maurten Gel 100 CAF 100 has 100 mg and costs R80 to R85. Test before race day. See caffeine gels.
What about race morning?
Eat a familiar carbohydrate-rich breakfast two to three hours before the start, sip fluid, and carb load the day before (how to carb load). Avoid new foods, high-fibre meals and large amounts of caffeine.
Common mistakes
- Starting the bike too hard and running out of fuel on the run.
- Switching to gels you have never tried.
- Relying on salt tablets for cramps, which are not proven to prevent them.
- Skipping the swim-to-bike snack.
Who needs advice?
Diabetes, kidney or heart disease, pregnancy, and medication affecting fluid or blood pressure need individual plans from a doctor or dietitian; Ironman 70.3 is an adult event. Treat heat illness (confusion, collapse) as an emergency.
Products mentioned, with dated prices
| Product | Size | Price | Servings | R per serving | Sweeteners |
|---|---|---|---|---|---|
| 32Gi Race High Intensity Sports Drink (900 g) | 900 g | R470Dis-Chem Living Fit, Oct 2026 | 12 | R39.17 | None listed |
| Biogen Elite Carb Energy Gel, unflavoured (60 g) | 60 g sachet | R44.99Dis-Chem Living Fit, Oct 2026 | 1 | R44.99 | None listed |
| Science in Sport (SiS) GO Isotonic Energy Gel (60 ml) | 60 ml sachet | R45–R49Sportsmans Warehouse via PriceCheck, Oct 2026 | 1 | R44.90 | None listed |
| Maurten Gel 100 CAF 100 (40 g sachet) | 40 g sachet | R80–R85biket / goneoutdoor via PriceCheck, Oct 2026 | 1 | R85.00 | None listed |
| Biogen Electrolyte (3 x 10 sachets, citrus) | 3 x 10 sachets | R139–R155Dis-Chem (electrolytes group), Oct 2026 | 30 | R5.17 | Not published |
Related questions
- What is the best carb drink for cycling in South Africa?
- How many carbs per hour do you need for a marathon or ultra?
- Do caffeine gels improve endurance performance?
- How do you stay hydrated training in summer heat in South Africa?
- How should you fuel for the Cape Town Cycle Tour?
Sources
- Jeukendrup 2014, A step towards personalized sports nutrition: carbohydrate intake during exercise (Sports Med)
- Guest et al. 2021, ISSN position stand: caffeine and exercise performance (JISSN)
- Hew-Butler et al. 2015, Third International Exercise-Associated Hyponatremia Consensus Statement (BJSM 49:1432)
- Thomas, Erdman & Burke 2016, Position of the Academy of Nutrition and Dietetics, Dietitians of Canada and ACSM: Nutrition and Athletic Performance
Educational information only, not medical advice. Speak to a doctor, pharmacist or registered dietitian before using supplements if you are pregnant or breastfeeding, under 18, taking medication, or living with kidney, liver or heart disease.
Cite this page: Healthnews24, “How should you fuel for Ironman 70.3 South Africa?”, updated 27 October 2026, https://www.healthnews24.co.za/answers/ironman-south-africa-nutrition-plan/. Plain-text version: /answers/ironman-south-africa-nutrition-plan.md