What is the Paleo diet, and is it suitable for a triathlete training for an Ironman?

Heard that the Paleo diet can help you lose weight, but unsure whether it's suitable to fuel your Ironman training? James Witts explains...

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 The Paleo diet reflects the eating habits of our pre-agricultural ancestors. That means goodbye potatoes, legumes and grains, and hello meat, fish, eggs, fruit and veg. As a result, it’s rich in omega-3 and protein to beat heart disease and repair muscle, respectively.


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How to fuel the Ironman

But the problem is a lack of carbs that, while arguably of more importance over shorter, faster triathlons, remain vital over long course to fuel high-intensity sessions. They’re also linked to a stronger immune system.

While there have been examples of successful long-course triathletes adhering to all things Paleo, including former Ultraman champion Jonas Colting, we’d still recommend returning to carbs.

It’s difficult to be specific about quantity without knowing your weekly training volume and intensity but we presume you’re training upwards of 8-10hrs.

Average carb intake sits around the 5g/kg bodyweight mark. This could easily rise to 8g/kg bodyweight, especially when training twice a day. As an example, a 75kg triathlete would see their daily carb intake grow from 375g to 600g per day. “And I’d suggest consuming several smaller meals and snacks throughout the day rather than one or two really large meals,” says Kevin Currell, head of performance nutrition at the English Institute of Sport. “This’ll deliver a more consistent flow of slow-release energy.”

These carbohydrates should be of good quality – wholemeal rice over white, for instance – and certainly shouldn’t mean chowing down on five or six energy bars. In fact, you should reserve energy bars for long bike rides or even make your own.

That said, don’t drown in carbs; they’re just one of the three macro-nutrients that’ll fuel your Ironman best. Aim for around 1.4g/kg protein to rebuild muscles and don’t neglect the good fats that feature on the Paleo diet, which should account for around 20-30% of your calories. Omega-3, in particular, is beneficial for health and performance, with studies showing it protects the heart, controls blood pressure and maintains a lean bodyweight. Oily fish is ideal, but nuts, chia seeds and flaxseed oil are also good sources.

Antioxidant intake is also even more important than normal when training for an Ironman as your immune system’s stretched to breaking point. So include a variety of different-coloured foods in your diet, like blueberries, spinach, sweet potato and tomatoes. These’ll fill your body with vitamin C and phytochemicals to sweep up free radicals and keep you healthy.

Finally, hydration. The extra training and sweat loss means 12 to 16 glasses of water daily isn’t uncommon. Electrolytes add taste and nutrients.


James Witts specialises in sport science and endurance sport. He’s also the author of The Science of The Tour de France

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