Triathlon diet: sugar intake

Dietician and sports nutritionist Renee McGregor discusses the right amount of sugar for a triathlete in training


The current guidelines suggest that simple (or ‘extrinsic’) sugars should make up no more than 5% of total energy intake, with a maximum of 30g a day. This includes white table sugar (sucrose), brown sugar, honey and high fructose corn syrup.


If, for example, you’re consuming 3,000Kcals a day then your total amount of extrinsic sugar should be no more than 150Kcals. This excludes sugar naturally found in fruit or milk, (lactose), known as intrinsic sugar.

It’s worth bearing in mind these guidelines have been produced with the general population in mind – and specifically those who may be overweight, living pretty sedentary lifestyles and consuming large quantities of extrinsic sugar.

For an active triathlete, while I’d still encourage you to keep extrinsic sugar intake minimal, it’s more important to think about your overall fuelling considering you’re putting your body under considerably more stress than the general population. If you’re doing a training session of 90mins or more, you may find that you’ll benefit from taking on some simple sugar. Examples would be a gel or a handful of jelly babies to maintain your pace and keep your carbohydrate stores topped up for the duration of the session – around 30-60g of carbs per hour.

Similarly after high-intensity training, it’s important to replace glycogen stores quickly, especially if you have another training session within eight hours. A quick way to do this is to consume some readily available carbohydrate, in the form of simple sugars; a good example is chocolate milk, which contains milk sugar but also additional sugar.


So while we should be wary of sugar, it shouldn’t be demonised – it may contribute to higher energy intake, but it doesn’t actually cause obesity per se. It’s likely that with a moderate to high training load you’ll achieve energy balance, and lucky for you that means you don’t have to be as vigilant over your sugar intake as the official guidelines recommend.