@Miroslav Havel, welcome and brilliant question. This is one I love digging into. Your instinct around 3,000 kcal is actually really close to what the research shows. A 2021 study looking at male academy soccer players from English Premier League academies found that U12/13 players had a total energy expenditure of around 2,859 kcal per day on average. With the range going up to 3,903 kcal per day for some individuals. So yes, 3,000 kcal is very much in the right ballpark for an active boy at that age, and for some it's actually conservative. What's also worth noting. This was elite academy level. Your child's needs will depend on their individual size, weight, growth stage, playing position, time of the season, position they play, playing style and training load, so it's not one number fits all. But the key takeaway is that active kids at this age genuinely need a lot more than most parents expect. Underfuelling is far more common than overfuelling at this age. I use an energy calculator to work this out individually, which gives a much more accurate picture than a general estimate. Happy to walk you through it and show you how I'd calculate your child's specific needs if you'd like 🙌