"I would much rather have a little bit too much in my body than a little bit too less, because that’s when things start to go wrong." - Tom Evans
Speaking on his podcast, The Ultra Sound, ultra-endurance runner Tom Evans breaks down how he decides how much fuel to take on during long races - and why copying what the pros do without understanding your own body can be risky.
On the surface, Tom's numbers stand out - he aims for 115 to 120 grams of carbohydrates per hour. But the thinking behind them is far more important than the number itself.
"I think a lot of people look at the pros now and a lot of people are saying the more carbohydrate the better, and for me to a certain extent that is the case," says Tom.
"But there is definitely a sweet spot for everyone."
For Tom, that sweet spot isn’t based on trends or guesswork - it’s based on understanding cost.
"I think old sports science thinking was that around 60 to 80 grams an hour was plenty," he says.
"But I’ve been to the lab and been fortunate enough to get tested to see how much it costs my body to move. And that’s the most accurate way of doing it, because you wouldn’t know for sure otherwise."
That testing helped Tom frame fuelling in a way that’s easy to understand - and easy to get wrong.
"I guess it’s a little bit like driving a car," he says.
"If your foot is just constantly on the accelerator you’re going to burn through fuel much faster because you’re not being that economical.
"But if you’re cruising around driving really sensibly — like an ultra race would be — then you’re not burning as much."
Ultra racing, for Tom, isn’t about max effort. It’s about efficiency, restraint and staying ahead of the problem before it arrives.
"I would much rather have a little bit too much in my body than a little bit too less, because that’s when things start to go wrong."
The message isn’t just for ultra runners. Whether you’re training for an event or trying to stay consistent week to week, Tom’s logic holds:
Understand how hard you’re working. Match your fuel to the cost. And remember - running out is always more expensive than carrying a little extra.
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