Carbohydrates for performance

How much carbohydrate do you need?

Sports nutrition guidelines scale carbohydrate to how much and how hard you train. These figures were developed for athletes, so treat them as a ceiling that rises with training volume rather than a target everyone must hit.

• Light training or skill work: around 3 to 5 g per kg per day
• About an hour of moderate to hard training most days: around 5 to 7 g per kg per day
• One to three hours of hard training a day: around 6 to 10 g per kg per day

For someone doing four or five hour-long sessions a week, 3 to 5 g per kg is a practical range. A 70 kg person would eat around 210 to 350 g a day. If you are in a heavy HYROX block with running on top of classes, you will likely need more, particularly on your biggest days.

If fat loss is the goal, carbs are usually where some of the calorie reduction comes from, but not all of it. Cutting them to the bone tends to wreck training quality, which is covered in our guide to low-carb versus low-fat diets.

Choosing the right carbs

The NHS Eatwell Guide suggests starchy carbohydrates make up just over a third of what you eat, choosing wholegrain or higher fibre versions where you can. For most meals, that advice suits training well.

• Everyday base: oats, wholemeal bread, brown rice, wholewheat pasta, potatoes with skins, beans, lentils and fruit. These bring fibre, vitamins and steadier energy.
• Close to training: white rice, bagels, white bread, bananas, rice cakes and dried fruit. Lower fibre means they digest faster and are less likely to cause stomach trouble.
• During long sessions or races: sports drinks, gels, jelly sweets or diluted juice. Simple sugars are exactly what you want here.

Sugar gets a bad name, and for everyday eating that is mostly deserved. During a 90 minute session, though, it is fuel doing its job. Our guide to sugar explains where the line sits.

Portion size is the lever that matters most. A fist-sized portion of rice, pasta or potatoes at each meal suits most people on training days, with a little less on rest days.

Timing carbs around your week

You do not need the same amount of carbohydrate every day. A simple approach is to eat more on your hardest days and around your hardest sessions, and a bit less on rest days and light days.

For example, someone who does Full Body at Lycan Strength on a Monday, Engine on Wednesday and Lower on Thursday might have larger portions of rice or potatoes at the meals before and after those sessions, and smaller portions on Tuesday, Friday and at the weekend. Protein stays the same every day. Only the carb portion moves.

During sessions lasting over an hour, taking in 30 to 60 g of carbohydrate per hour can help maintain output. That is about 500 ml of a standard sports drink or a gel plus water. Very long efforts of two and a half hours or more may call for more, but that is beyond what most gym athletes need.

Does low-carb hurt performance?

Low-carb and ketogenic diets can work for weight loss and some people enjoy them. For training performance, especially high-intensity work, the picture is less positive. Research on trained athletes consistently finds that very low carbohydrate diets reduce the ability to sustain hard efforts, even after weeks of adaptation.

For strength training, the effect is smaller but still noticeable in high-rep, high-volume sessions. For HYROX, which mixes running with repeated hard stations, low glycogen is a real handicap. If you want to try low-carb, do it in a period where performance is not your priority, and expect your conditioning to suffer at first.

Anyone with type 1 or type 2 diabetes should plan carbohydrate around training with their GP or diabetes team, because medication and blood sugar management change the rules.

Carb-loading for a race

Carb-loading means eating much more carbohydrate than usual, often 8 to 10 g per kg a day, for one to two days before an endurance event while training lightly. It fills glycogen stores to the top and helps in events lasting roughly 90 minutes or longer.

Many HYROX finishers take somewhere between one and two hours, so a full load is not essential for everyone. A sensible middle ground is to eat a bit more carbohydrate than usual the day before, keep fibre and fat moderate so your stomach is settled, and have a familiar carb-based breakfast. The HYROX taper guide covers how to fit this into race week, and our nutrition for HYROX training guide covers the weeks before.