In 30 seconds
- People who do CrossFit often fall short on carbohydrates: about 3.6 g per kilo a day, when the reference for an hour of training a day is 5-7 g.
- Protein, 1.4-2.0 g per kilo a day, spread across servings of 20-40 g every 3-4 hours.
- In a WOD lasting less than an hour, water to thirst is enough. In longer sessions or in the heat, a drink with carbohydrates and sodium.
- At 3 g a day: “Creatine increases physical performance in successive bursts of short-term, high intensity exercise.” And a bad night takes 6% off interval exercise.
A 15-minute WOD may seem short, but it is one of the most demanding efforts you can make. Nutrition for CrossFit and HIIT rests on four pillars: enough carbohydrates, protein spread through the day, sensible drinking and good sleep. This guide turns all that into figures and a plan for your week.
The essentials in 6 steps
- Eat enough carbohydrates: 5-7 g per kilo a day if you train for an hour a day. This is where people who do CrossFit most often fall short.
- Spread your protein: 1.4-2.0 g per kilo a day, in servings of 20-40 g every 3-4 hours.
- Arrive at your WOD fuelled: a meal 2-4 hours beforehand, or something small if it is less than an hour away.
- Drink to thirst: in short sessions water is enough; in long ones or in the heat, carbohydrates and sodium.
- Recover well: protein and carbohydrates in the following hours, especially if you train twice in a day.
- Sleep at least 7 hours: a bad night takes about 6% off interval performance, so good sleep is part of your training.
Carbohydrates per kilo a day
In CrossFit, the average falls short
Why high intensity needs fuel
In a WOD you alternate short, intense efforts, lifts and conditioning work with little rest. Sports nutrition guidelines adjust carbohydrates to how much you train, and an hour a day already calls for 5-7 g per kilo 2.
Even so, people who do CrossFit often fall short. A 2025 review pooled 49 studies: on average, participants eat about 3.6 g of carbohydrates per kilo a day, below what is recommended. And the figure has been falling in recent years 1. Protein, on the other hand, is well covered: about 1.7 g per kilo 1.
Carbohydrates: how much a day
The reference depends on how much you train 2:
| Your weight | Easy or technique days (3-5 g/kg) | Days with 1 hour of training (5-7 g/kg) |
|---|---|---|
| 60 kg | 180-300 g | 300-420 g |
| 70 kg | 210-350 g | 350-490 g |
| 80 kg | 240-400 g | 400-560 g |
| 90 kg | 270-450 g | 450-630 g |
Ranges from Burke et al., 2011, and Thomas et al., 2016. If you train for more than an hour a day at high intensity, the reference rises to 6-10 g/kg.
Does it show in your training? In three CrossFit studies, higher-carbohydrate diets were associated with better performance, with a moderate effect 1. In one of them, 18 people trained for 9 days. Those who increased to 6-8 g per kilo for the last 3 days did 15.2 more repetitions in a 12-minute WOD (+10.9%). Those who stayed below 6 g did 5.7 more (+4.2%) 3.
The difference between groups did not reach significance. The authors believe that eating slightly fewer carbohydrates may be enough for a few days, but that over longer training periods the effect could be more noticeable 3.
And the ketogenic diet? In the two studies that have tested it in CrossFit, it did not improve performance 1.
In practice:
- Include carbohydrates at every meal: rice, pasta, potatoes, bread, pulses, oats or fruit.
- More on hard days, less on easy ones: adjust the portion to your training, not the other way round.
Protein: how much and how to spread it
The International Society of Sports Nutrition (ISSN) recommends 1.4-2.0 g per kilo a day for most people who train 4:
| Your weight | Per day (1.4-2.0 g/kg) | Per serving (0.25 g/kg) |
|---|---|---|
| 60 kg | 85-120 g | 15 g (20 g is better) |
| 70 kg | 100-140 g | about 20 g |
| 80 kg | 110-160 g | about 20 g |
| 90 kg | 125-180 g | about 25 g |
Source: ISSN position stand (Jäger et al., 2017). The reference per serving is 0.25 g/kg or 20-40 g. Figures rounded.
More than the total, what counts is how you spread it 4:
- Servings of 20-40 g, or about 0.25 g per kilo, every 3-4 hours.
- With 700-3,000 mg of leucine per serving: choose complete proteins, with all the essential amino acids.
- Before bed: a serving of 30-40 g of casein increases muscle protein synthesis overnight.
If your breakfast or dinner falls short on protein, a shake is a practical way to top it up with few calories 4.
Before, during and after the WOD
| When | What to do |
|---|---|
| 2-4 hours before | A meal with carbohydrates (1-4 g/kg), some protein and little fat and fibre. Drink 5-10 ml of water per kilo. |
| Less than 1 hour before | If you feel like it, something small: 25-30 g of carbohydrates, low in fibre, fat and protein. |
| During (less than 1 hour) | Water to thirst. Carbohydrates are not needed. |
| During (more than 1 hour or in the heat) | A drink with carbohydrates and 400-1,100 mg of sodium per litre, in sips. |
| After | 20-40 g of protein within the next 2 hours, with carbohydrates. Replace the weight lost with fluid. |
| If you train twice the same day | Carbohydrates straight away: 1-1.2 g per kilo per hour for the first few hours. |
Sources: Burke et al., 2011, and Thomas et al., 2016, summarised by the GSSI; ISSN (Kerksick et al., 2017); German Nutrition Society (Mosler et al., 2020).
Before
Ideally, a meal with 1-4 g of carbohydrates per kilo between 1 and 4 hours beforehand. If it is less than an hour away, something small, with about 25-30 g of carbohydrates, low in fibre, fat and protein 2. And start well hydrated: 5-10 ml of water per kilo in the 2-4 hours beforehand 6.
Do you need a snack just before the class? In CrossFit, taking carbohydrates just before or during the session did not improve performance in three studies 1. What matters is having eaten well in the hours beforehand. You will find options and timings in what to have before training.
During
- Sessions of less than 30 minutes: you do not need carbohydrates 2.
- Strength training: you do not need them during the session either 2.
- One-hour classes: drink water when you are thirsty. Up to about 60 minutes, you do not need anything else 6.
- Sessions longer than an hour, competitions or heat: a drink with carbohydrates and 400-1,100 mg of sodium per litre 6.
After
Protein taken between straight after and 2 hours after training strongly stimulates muscle protein synthesis 5. Have it with carbohydrates to refuel.
If you do two sessions on the same day, recovery is urgent. Guidelines suggest 1-1.2 g of carbohydrates per kilo per hour for the first few hours 2. Or a mix of 0.8 g of carbohydrates and 0.2-0.4 g of protein per kilo per hour 5.
For fluid, if you have lost weight while training, replace around 1.5 litres for every kilo lost. If the loss is small and you are not training again within 24 hours, your meals and water are enough 6.
Staying hydrated in class
If you train in a poorly ventilated space, you will feel the heat in summer. Three simple ideas:
- Weigh yourself before and after a class one day: it is the most reliable guide to how much you sweat and how much to drink 6.
- Drink to thirst: drinking beyond it has no advantages 6.
- In the heat, sodium: in long sessions, a drink with 400-1,100 mg of sodium per litre helps you replace what you lose in sweat 6.
How it works
Energy for short, intense efforts
Creatine: short, intense efforts
It is one of the most used supplements in CrossFit: between 26 and 61% of participants take it, depending on the study 1. European regulations authorise this claim. Creatine increases physical performance in successive bursts of short-term, high intensity exercise. The beneficial effect is obtained with a daily intake of 3 g of creatine 7. A varied and balanced diet and a healthy lifestyle are important.
That is exactly what a WOD is: short, intense efforts, one after another.
- How much: 3 g a day, including rest days. AESAN, Spain's food safety agency, considers this amount safe and acceptable as a supplement for healthy adults 8.
- When: every day. Dissolved in your bottle, it is one less thing to remember.
- Who should not: if you have kidney disease, it should not be taken; if you are pregnant or breastfeeding, check with your doctor 8.
Our Creatine monohydrate is micronised to 200 mesh, unflavoured and with no other ingredients. One scoop is your 3 g a day, at €0.17 a day.
Caffeine and other supplements
- Caffeine: in CrossFit, four studies with 73 people showed a moderate but inconclusive effect 1. If you use it, watch the dose and the timing, especially if you train in the afternoon. We explain it in caffeine and performance.
- Beta-alanine: in the only CrossFit study, 6.4 g a day for 28 days did not change performance 1.
- Bicarbonate: three studies with mixed results 1.
Food, hydration and rest remain the foundation. With those in place, creatine is the supplement that fits this type of training most closely.
After a bad night
How much your performance drops with too little sleep
Sleep: the training no one sees
The American Academy of Sleep Medicine recommends 7 hours or more a night for adults 10. If you train regularly, it is part of the plan.
A meta-analysis of 77 studies measured what happens after a night of short sleep or no sleep 9:
- Overall performance: 7.6% lower.
- High-intensity interval exercise: 6.2% lower.
- Anaerobic power: 6.3% lower.
- Strength: 2.9% lower.
The effect was greater in afternoon tests, just when many people train 9. You will find all the data in sleep deprivation and performance.
A typical day
| Time | What to eat or drink |
|---|---|
| 8:00 | Breakfast with protein and carbohydrates: yoghurt or milk, eggs, bread or oats, and fruit. |
| 11:30 | A snack if you need one: fruit and a handful of nuts, or a dairy product. |
| 14:00 | A full lunch: rice, pasta or potatoes, chicken, fish or pulses, and vegetables. |
| 17:00 | A light afternoon snack: toast with ham and fruit. Keep sipping water. |
| 19:00 | WOD. Water to thirst, or your isotonic drink if the session lasts more than an hour or it is hot. Your 3 g of creatine, in your bottle. |
| 21:00 | Dinner with 20-40 g of protein, carbohydrates and vegetables. |
| 23:00 | Bedtime: at least 7 hours. No caffeine from mid-afternoon. |
An example for guidance. Adjust the amounts to your weight, your goal and the length of your session.
Common mistakes
- Running low on carbohydrates: the most frequent mistake in CrossFit, according to the studies 1.
- Concentrating protein at dinner: it is better spread across 3-5 servings.
- Doing an intense WOD fasted: if you feel low on energy, try eating something 1-2 hours beforehand.
- Recovering with protein alone: carbohydrates are also needed afterwards, especially if you train twice in a day.
- Sleeping 5-6 hours and expecting to progress: rest is training too.
Nitrus, creatine and the Strength Pack
Nitrus Isotonic is our electrolyte hydration drink for your training sessions. Each 25 g serving in 400-500 ml provides about 15 g of carbohydrates and five electrolytes, with 195 mg of sodium. It adds all 13 vitamins, 1 g of BCAAs, glutamine and 200 mg of taurine. Riboflavin (vitamin B2), vitamins B6, B12 and C, niacin, pantothenic acid and folate contribute to the reduction of tiredness and fatigue.
You can dissolve your 3 g of creatine in the same bottle. And if you want everything together, the Strength Pack brings together creatine, BCAAs and Nitrus for €55.90, with free delivery.
Frequently asked questions
How many carbs do I need if I do CrossFit?
The reference for an hour of training a day is 5-7 g per kilo of body weight a day, and 3-5 g on easy days. Studies find that people who do CrossFit tend to eat considerably less, about 3.6 g per kilo.
What should I eat before a WOD?
A meal with carbohydrates, some protein and little fat and fibre 2-4 hours beforehand. If you only have an hour, something small and easy to digest, such as a banana or toast with jam.
Should you drink during a WOD?
In sessions of less than an hour, drinking water when you are thirsty is enough. If the session lasts more than an hour, you sweat a lot or it is hot, a drink with carbohydrates and sodium helps you replace what you lose.
Is creatine useful for CrossFit?
European regulations authorise this claim: “Creatine increases physical performance in successive bursts of short-term, high intensity exercise.” The beneficial effect is obtained with a daily intake of 3 g of creatine. A WOD strings together short, intense efforts.
Is the keto diet good for CrossFit?
There is no evidence that it is. In the two studies that have tested it in CrossFit, it did not improve performance. In three studies, on the other hand, higher-carbohydrate diets were associated with better performance.
Sources
- Martinho DV, Rebelo A, Clemente FM, et al. Nutrition in CrossFit: scientific evidence and practical perspectives, a systematic scoping review. J Int Soc Sports Nutr. 2025;22(1):2509674. View publication
- Burke LM, Hawley JA, Wong SH, Jeukendrup AE. Carbohydrates for training and competition. J Sports Sci. 2011;29(Suppl 1):S17-S27. View publication
- Escobar KA, Morales J, VanDusseldorp TA. The effect of a moderately low and high carbohydrate intake on CrossFit performance. Int J Exerc Sci. 2016;9(4):460-470. View publication
- Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20. View publication
- Kerksick CM, Arent S, Schoenfeld BJ, et al. International society of sports nutrition position stand: nutrient timing. J Int Soc Sports Nutr. 2017;14:33. View publication
- Mosler S, Braun H, Carlsohn A, et al. Position of the working group sports nutrition of the German Nutrition Society (DGE): fluid replacement in sports. Dtsch Z Sportmed. 2020;71(7-9):178-184. View publication
- Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods. View publication
- AESAN Scientific Committee. Report on the risk associated with the consumption of food supplements containing creatine as an ingredient. Journal of the AESAN Scientific Committee. 2024;39:47-62. View publication
- Craven J, McCartney D, Desbrow B, Sabapathy S, Bellinger P, Roberts L, Irwin C. Effects of acute sleep loss on physical performance: a systematic and meta-analytical review. Sports Med. 2022;52(11):2669-2690. View publication
- Watson NF, Badr MS, Belenky G, et al. Recommended amount of sleep for a healthy adult: a joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep. 2015;38(6):843-844. View publication
Information based on published studies. It does not replace the advice of a doctor or registered dietitian. The results describe what was measured in each study, not the properties of any specific product.
