"First of, HIIT training is hard. Its super intense and during those sessions you're not likely to get in a lot of water, so the first thing to mention would be to make sure you're well hydrated before you start your workout.
But the worst part, I find, is that you always feel hungry and exhausted straight afterwards and even the morning after! Once those post workout endorphins (you know - the things that make you feel good) have worn off and the high has gone, it's really tempting to reach for something sugary as a pick me up to keep the energy levels high, or even as treat for your hard work. We've all been there - but it can actually do more harm than good!
Whatever you are training for, whether it's for an event or just because it's your New Years Resolution (congrats on making it this far!), it's so important your diet is right. Whatever you are putting into your body, you need to output the right energy to perform at your best - and this doesn't just go for athletes! If it's going to take you a while home and you cant resist the urge to snack, why not have a quick protein shake before you get home and can fix yourself up a proper dinner.
Personally, I think the best thing to have after a HIIT workout is a protein shake. Whenever you do a HIIT workout you get small tears in your muscles (don't worry these micro-tears are a good thing!). As these tears recover, the muscle fibers rebuild stronger. Protein is perfect for recovery as it is easily absorbed and it helps to replenish your muscles. Even the next morning, if you're aching like hell, an easily digested protein shake will do wonders!
As mentioned before, your diet is key and it is best to stick to lean protein powders rather than meal replacement shakes. Post workout, you are going to be hungry, and so more than anything, it's a great excuse to fill your plate with a lot of greens and some lean protein. But greens should be the most prominent thing you see on your plate.
Remember though, every single body is different, and you should always listen to your own body and tailor to your own needs. But it's what you put in that helps how you perform!"