Guidance is mixed about what you should be eating before a big session, whether it’s a running session or a CrossFit session. As science dives deeper into this stuff more concrete guidance will come out over time, but for now we’ve got some pretty good guidelines that should help you feel better when you’re getting into a longer session.
If you think that your heart rate is likely to be significantly elevated for an extended period of time then it may be worth eating something pre-training to make sure your fuel stores are maximised.
If you’re doing 45-60 minutes of mixed training then it’s unlikely that you’ll need much pre-training as your food intake throughout the rest of the day should cover you.
When you start to extend the time frames out past 60 minutes, or anticipate going HARD for 30-40 minutes, it may be worth starting to look at the pre-training snack…
So, for shorter sessions a little snack of 0.5-1g of carbs per kg of bodyweight with 0.25-0.5g of protein per kg of bodyweight will be plenty about 30-60 minutes before. That could be as simple as mixing some protein powder into some fruit juice, having a few slices of cooked meat with a banana or two or a can of tuna with a sweet potato (remember you don’t want it coming back up so it has to settle quickly in your stomach). Avoid fatty foods, avoid foods high in fibre and unless you deal really well with spicy stuff leave it for another time – your guts will thank you!
If you’re going longer than that then you can start to think about 1-2g of carbs per kg of bodyweight with 0.25-0.5g of protein per kg of bodyweight. As the amount of carbs goes up it’s probably worth moving to liquid foods so that you’ve not got a belly full of food sloshing around as you get moving!