How to prioritise your nutrition to your triathlon training

Matching your nutritional intake to the training you’re doing (nutritional periodisation) can really help you get the best out of your sessions, says Nigel Mitchell

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So what do we mean when we talk about nutritional periodisation? Well, put simply, it means you alter your nutrition to fit the goals of your training. And it’s something that people often get wrong, yet it’s so easy to get right.


Fuel and training 

You’ll often find that we under-eat on hard sessions and overeat on easy sessions. But one of the current trends is to train in a low carbohydrate state. Training fasted will increase fat oxidation and may improve your aerobic capacity – in other words, endurance. However, if this is all an athlete does, they just become a diesel engine – they keep going all day but with no real oomph. 

Most of you will also do a combination of training sessions – some long and steady, and some with more intensity. The idea of the higher-intensity training is that it prepares the body to perform at higher intensities, in effect functioning in a more anaerobic and carbohydrate-burning way. During these sessions, especially on the bike, the body burns a great deal of carbohydrate. If the athlete doesn’t have the carbohydrate in the body, it simply can’t do the work. 

One tool to check that you’re getting this right is to measure lactate levels after intensive exercise. Many athletes think that lactate is a bad thing, that it’s the cause of sore muscles. This is a complete myth. Without lactate we could not do any high-intensity exercise. If you’re trying to train hard but have low lactate levels, this suggests insufficient muscle glycogen stores, which will compromise training, because after hard exercise lactate is used as fuel for muscles, such
as the heart.

So how do we get it right?

Fuel for the work that you’re doing. If you’re heading into a steady session aimed at promoting endurance, go for a low-carbohydrate breakfast – for example, an omelette and an avocado. I don’t advise athletes undertake long training sessions fully fasted, because it can compromise the immune system and can also be difficult mentally.

If the pros are doing a session lasting three hours or more, we’ll give them a bottle of protein. The contents don’t need to be carb-free, but should be low-carb and should supply about 20g of protein. This won’t flood the system with carbohydrate; however, some of the protein will be converted to carbohydrate, helping to maintain blood-sugar levels. When trying these sessions for the first time, it’s a good idea to start to eat after about 90 minutes – begin with something like a small banana, then continue to eat about every 20 minutes. 

On the flipside, if you’re planning a harder training session then eating carbohydrate beforehand is beneficial; good old porridge oats is a fine choice. Oats are the breakfast of choice for most pro cyclists, providing slow-release energy over several hours. Sprinkle some milled seeds on top of your porridge for extra-slow energy and healthy fats.

Train smarter

Training intensities are so important. On the bike, the best way to monitor intensity of effort is to use a power meter such as the Garmin Vector, or one of those by Stages or Pioneer. Combining monitoring your power with improving your nutrition planning is one of the most effective ways to maximise training and racing. 

The same principles can be applied to swimming and running – but you need to work more on heart rate and effort. If you’re doing a steady swim or run, then you don’t need to take on fuel during the session. However, if you’re doing really hard sets and speedwork, taking on carbohydrate can really benefit the session. Gels and energy drinks are probably the easiest to use; I normally suggest taking about 20-60g during a 60-90min high-intensity training session. If you’re doing repeats of long intervals such as 4 x 10mins, taking a gel after the second set can really help.

The one thing that all triathletes have in common is that there’s never enough time to do all the training you want. So the one takeaway tip from this month’s page is to think about what you’re doing, and maximise it by planning your nutrition carefully.

5 sports nutrition takeaway tips


When doing lower-intensity training, reduce the amount of food you eat before and during sessions. The important thing is to make sure that you keep within the desired work zone.


Don’t train completely fasted – an omelette is a great low-carb breakfast and very easy to prepare before training, or cook one the night before and eat it cold.


When you need to work hard, make sure you give your body the fuel it needs. Porridge makes a great breakfast and again is very easy to prepare.


Consider using a power meter to better monitor your work and maximise your nutrition, plus a HRM to keep intensity right when running or swimming.


Make sure you take on carbs doing high-intensity sessions. This will reduce the demand for fuel later on and help you to avoid a blowout.