Note: the following applies to only weights workouts, there are so many factors in cardio workouts (HIIT or steady state, goals, time of day, blah blah blah) that it's impossible to have one cookie-cuttered answer to post-cardio nutrition. After resistance training (weights), your body is in a glycogen-depleted and catabolic state. It hungers for nutrients, and bodybuilders can take advantage of the two times when the body is most receptive of food after the workout, these windows of opportunity called post-workout (pwo) and post-post-workout (ppwo, also confusingly called pwo in some circles). PWO Post-workout is up to 15-20 minutes after your workout, and this is where the body wants protein to repair your broken-down muscles and some simple carbs (sugars) to kickstart the repairing with a timely insulin spike. Hence, the pwo drink is usually some form of liquid protein + sugar. Studies show that the most optimal pwo combination is whey protein + dextrose/glucose (2:1 dextrose to whey specifically but this is individual, some people prefer 1:1 - I'm not anal about this myself, I tend to put in more carbs than protein but I don't make sure it's twice as much). Just because whey+dextrose is the optimal combination, it doesn't mean that other combinations don't work - far from it, your body will make use any protein and carbs you give it pwo, but fast-digesting proteins are best (whey and egg protein) along with simple sugars so your body doesn't have to bother doing much digestion, and get on with making your muscles bigger. Other pwo formulas can be protein + fruit juice, protein + fruit, protein + lucozade/soda, your body isn't picky carbs-wise, as long as there's some sugar there it'll thank you for it. You can also intake simple carbs like white pasta or white bread here, but the insulin spike will be lower, and if you can stomach solid food after squatting then you're a better man than me. PPWO The other time when the body is most receptive is 1hr - 1.5hrs after the post-workout drink/meal. This is the post-post-workout (ppwo) meal, where your body fancies protein and some slower carbs (mid-low GI, although it won't hurt to put in simple carbs too). Beef and potatoes, chicken and rice, tuna and pasta .. any such combination is fine. It has been suggested that a liquid ppwo meal gives the body less work to do digestion-wise and so is better, but I believe that the benefits of solid food outweight the faster absorption and therefore wouldn't choose liquid pwo AND ppwo meals (all this liquid malarkey makes me hungry anyway). Fat and PWO/PPWO Fat slows down digestion, so for obvious reasons shouldn't be included in the pwo drink. Nutrionalists say that you need a balanced ppwo meal and should include some fat, I've never consciously done this and it hasn't done me any harm, and I don't believe it'd make a huge difference anyway. Slow Carbs and PWO Now, if your ppwo meal is going to be a long time after pwo (say 2 hours plus, without wanting to place an absolute value on the time) then you can to an extent counter-act this by including complex carbs in your pwo meal (wholemeal bread, wholewheat pasta, oats, etc). This means your body will have something to work with in the longer wait until ppwo. Recap Post-workout/PWO: up to 15-20 minutes after your weights workout, optimal combination whey + dextrose but any fast protein + simple sugars will do, NO FAT, include complex carbs if 2 hours or so away from ppwo. Post-post-workout/PPWO: 1-1.5hrs after pwo, should be any form of protein + complex carbs (low to mid GI), plus some simple carbs if you like (not recommended if bodyfat a serious issue), a little fat shouldn't hurt either but not critical to include.