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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 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.
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.
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.
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.
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.
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.
| Product | Size | Price (source, date) | Servings | R per serving | Sweeteners |
|---|---|---|---|---|---|
| 32Gi Race High Intensity Sports Drink (900 g) | 900 g | R470 (Dis-Chem Living Fit, 2026-10) | 12 | R39.17 | None listed |
| Biogen Elite Carb Energy Gel, unflavoured (60 g) | 60 g sachet | R44.99 (Dis-Chem Living Fit, 2026-10) | 1 | R44.99 | None listed |
| Science in Sport (SiS) GO Isotonic Energy Gel (60 ml) | 60 ml sachet | R45–R49 (Sportsmans Warehouse via PriceCheck, 2026-10) | 1 | R44.90 | None listed |
| Maurten Gel 100 CAF 100 (40 g sachet) | 40 g sachet | R80–R85 (biket / goneoutdoor via PriceCheck, 2026-10) | 1 | R85.00 | None listed |
| Biogen Electrolyte (3 x 10 sachets, citrus) | 3 x 10 sachets | R139–R155 (Dis-Chem (electrolytes group), 2026-10) | 30 | R5.17 | Not published |
Educational information, 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. Prices were observed in October 2026 and are not offers.