Carbohydrate Periodisation: How to Match Your Fuel to Your Training

Low-carb, high-carb, simple carb, complex carb and now carbohydrate periodisation!

I suspect it drives you a little crazy sometimes. You just want to eat the right nutrition and fuel training. You want to recover properly and perform at your best. And perhaps you’d also like to improve your body composition along the way.

You want it all, don’t you? Productive training, excellent recovery, steady progress towards your goals and a body that’s capable of doing what you ask of it.

So, let’s talk carbohydrate periodisation.

It’s a big topic, but let’s start with the basics: what it is, why it can be useful and how you might begin to apply it to your own training.

A little about carbohydrate and fat

Carbohydrate and fat are both important sources of energy. Your body can use either, or a combination of the two, to fuel training. The balance depends on several things, including exercise intensity, duration, training status and how much carbohydrate is available.

Here are a few things worth understanding before we get into the practical stuff.

• Carbohydrate is an important fuel for exercise, particularly as intensity increases. It can be used to produce energy rapidly when your muscles need to work hard.
• Your body stores carbohydrate as glycogen, mainly in your muscles and liver. These stores are limited, which is one reason fuelling becomes increasingly important during prolonged exercise.
• Fat is another valuable fuel source. We carry considerably more energy in our fat stores than we can store as glycogen, but the rate at which we can release and use that energy depends on the demands being placed on the body.
• Your body uses a mixture of carbohydrate and fat during exercise. The proportions change according to the work you’re doing and the fuel available.
• Carbohydrate availability matters. When you’re asking your body to produce energy quickly, having enough carbohydrate available can make a real difference to your ability to sustain the effort.

And here’s an important point: using a greater proportion of fat during exercise doesn’t automatically mean you’ll lose more body fat. 

Changes in body composition depend on the bigger picture, including overall energy intake and expenditure, training, recovery and individual circumstances.

This is where carbohydrate periodisation becomes interesting.

What is carbohydrate periodisation?

Put simply, carbohydrate periodisation means matching your carbohydrate intake to the demands and purpose of your training.

Think about your training week for a moment.

You might have a hard interval session designed to improve your ability to sustain high power. Another day might involve an easy recovery ride. At the weekend, you could be heading out for several hours of steady endurance work.

Would you approach all three sessions in exactly the same way?

Probably not.

Each session has a different purpose, places different demands on your body and creates different fuelling requirements.

Carbohydrate periodisation takes these differences into account. Rather than eating the same amount of carbohydrate regardless of what you’re doing, you adjust your intake to support the work that matters.

It doesn’t mean restricting carbohydrate for the sake of it. And it certainly doesn’t mean trying to complete every session with as little fuel as possible.

It’s about being more purposeful with your nutrition.

Why is it such a valuable tool?

Because your training has a purpose, and your nutrition should support it.

When you’re completing high-intensity intervals, sustained efforts at threshold or sessions that require repeated surges in power, carbohydrate availability becomes particularly important. These efforts place a high demand on your body’s ability to produce energy quickly.

If you deliberately restrict carbohydrate during these sessions in an attempt to burn more fat, you may find that you simply can’t produce the quality of work you’re aiming for. You might complete the session, but completing it isn’t necessarily the same as getting the intended training benefit.

Over time, repeatedly underfuelling demanding sessions can also compromise recovery and adaptation.

So, what about those easier rides?

During lower-intensity exercise, your body can generally derive a greater proportion of its energy from fat. Depending on the duration and purpose of the session, you may not need as much carbohydrate during exercise as you would for a hard interval workout.

This is where a more targeted approach can be useful.

You might choose to consume less carbohydrate during a short, easy ride while ensuring that your overall nutrition still supports your energy needs, health and recovery.

But there’s an important distinction here.

Lower carbohydrate intake during a session is not the same as deliberately underfuelling your training.

Nor does a longer, lower-intensity ride automatically mean you should take in very little carbohydrate. Duration matters, too. A four-hour endurance ride still places substantial demands on your body, even when your heart rate stays relatively low.

The goal is to find the right balance for the session, the athlete and the wider training plan.

How do you get started?

This is where it can become a little more individual.

There isn’t one universal carbohydrate intake that works for every athlete or every session. Your requirements will depend on the type and duration of exercise, your training goals, your current fuelling habits, your overall energy intake and how well you’re recovering.

That said, you have to start somewhere. Here’s how I’d approach it.

1. Understand the purpose of each session

Before you think about carbohydrate grams, ask yourself what you’re trying to achieve.

Are you developing aerobic endurance? Working on sustained power? Completing high-intensity intervals? Recovering between demanding sessions?

Your answer helps determine how you should approach fuelling.

2. Start with appropriate fuelling

Make sure you’re supporting the work you’re asking your body to do. Harder and longer sessions generally require more attention to carbohydrate availability, while shorter, easier sessions may offer more flexibility.

If you’re training for several hours, remember that your fuelling needs are influenced by duration as well as intensity.

3. Pay attention to what happens during the session

How do you feel? Can you sustain the intended effort? Are you finishing strongly, or fading towards the end? Are you experiencing unusual hunger, fatigue or difficulty maintaining your power?

These observations can help you identify whether your current strategy is working.

4. Look beyond the bike

How you eat before and after training matters, too.

Are you starting sessions adequately fuelled? Are you replacing enough energy and carbohydrate after demanding exercise? Are you eating enough overall to support your training and recovery?

There’s little value in carefully adjusting carbohydrate intake on the bike if your overall nutrition leaves you consistently underfuelled.

5. Experiment thoughtfully

Once you understand your baseline, you can begin making small, purposeful adjustments.

For an appropriate, shorter, easy session, you might explore whether you need the same amount of carbohydrate during exercise as you do for a harder workout. You could then observe how you feel, how well you recover and whether the change fits your wider training goals.

Avoid changing everything at once. Give yourself enough time to recognise patterns, and don’t judge the success of a strategy by body weight or body fat alone.

The aim is to improve the relationship between your nutrition and your training, not to win a competition to see how little you can eat.

Connect your dots

This is the part I particularly enjoy when working one-to-one with athletes.

You begin to connect the dots between the purpose of each session, the carbohydrate you’re consuming, the quality of your training, how you feel afterwards and how well you’re recovering.

Over time, those observations help you understand what works for you.

And remember, what works during one phase of training may need to change when your workload increases, you’re preparing for an event or you’re completing several demanding sessions close together.

Carbohydrate periodisation isn’t a fixed formula that you work out once and follow forever. It’s a strategy that can evolve alongside your training.

For some athletes, it’s useful to consider the whole day rather than the session in isolation. Your pre-training meal, fuelling during exercise, post-training recovery and the rest of your day’s nutrition all contribute to the bigger picture.

That’s where the real value lies: in understanding how the different pieces fit together.

Make your nutrition work for you

The key to getting this right is learning to balance the demands of your training with your body’s need for energy, recovery and adaptation.

You don’t need to get everything perfect from day one. You need to understand what you’re trying to achieve, start with a sensible strategy and pay attention to how your body responds.

When I work with athletes, we look at their training, lifestyle, current nutrition and goals before deciding where adjustments might make a difference. We then review, learn and refine the approach as we go.

Because your nutrition should work for you, not become another complicated thing to manage.

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If you’d like help understanding how to fuel your training, improve recovery and make your nutrition work towards your performance goals, I’d love to hear from you.

At Nutrition with Jill, we build personalised nutrition strategies around you, your training and your life.