So you do running? or aerobic? or something else?
When you work out the right way, you burn alot of calories fast and you sweat ALOT so you lose alot of eletrolytes (which is like minerals). You need protein, carbs and fat. Healthy fat and beverages that contains what you can find in electrolytes.
You would need to gradually work it up. You don't work on the same area everyday. That part of the body needs to rest. and it gets sore if you don't.
You have to stay hydrated so much. ALOT of water. The easiest beverage people drink is sports drink like Power/Gatorade. They are high in sugar but I guess that's better than nothing. But, the better ones are purely fruit/veg drinks you can make (like the Naked brand beverage). Notice that Bananas are often given out after a race. Nuts and seeds. I would blend fruits/nuts/seeds/veg with almond milk or just water and drink it. Like a smoothie Maybe a glass before and a glass after a run. That's what I've been doing and it helps.
Don't skip meals. And don't eat right away after a workout. But, I noticed I have to increase my food amount cause I was just so hungry.