What should I eat while training for a half Ironman?

Training for a half Ironman – 1.9km swim, 90km bike and half-marathon run – is not a simple undertaking. But how do you get in enough calories to sustain the extra training and optimise your performance? Laura Tilt has this advice for a reader…

Close-up of athlete eating pasta dish

I’m 26 and training for a 70.3 race, but I’m really struggling with being hungry and what feels like all the time. I just never feel satiated now I’ve started my first 70.3 training plan. It must be inevitable at this rate that I will gain race fat instead of losing it. Can you help? Natasha Pearce


Although a certain amount of hunger can be expected at the start of a fat-loss journey, the fact that you’re hungry all the time suggests to me that you’re significantly under-fuelling for the amount of training you’ve started doing, and your body is simply sending out strong signals that it needs more energy.

How much food do I need to consume to train for a 70.3? 

It’s easy to underestimate how much fuel (particularly carbohydrate) you’ll need for a 70.3 training plan. Sports nutrition guidelines recommend 7-10g of carbohydrate per kilo of body weight when engaging in 1-3 hours of moderate to high-intensity exercise a day, or 5-7g/kg body weight for a moderate-intensity programme of up to an hour a day.

So, for example, if you weighed 70kg this would be somewhere between 350-490g a day for 1-2 hours, equivalent to 1,400-1,960kcal, and from this you’ll need to add protein and fat to meet your daily energy needs. It’s worth keeping a food diary for a few days and seeing how your carbohydrate and energy intake stacks up.

What happens if I under-fuel? 

Over time, under-fueling is going to compromise your training and performance and risk the loss of lean mass (being lighter but with less muscle isn’t typically a good thing), as well as hormonal imbalance, so I’d recommend evaluating your goals and thinking about whether fat loss is achievable/necessary during your training phase.

What’s the safest way to lose body fat?

Ideally, you’d lose weight in the off-season before a training block begins or in the base phase before it ramps up. If fat loss is something you want to pursue, it should be done very slowly, in order to preserve lean mass and performance, so cutting no more than 250 calories a day, or aiming to lose no more than around 0.5lb per week.

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