you don't need a special diet for martial arts, what called a balanced diet will do just fine. So somewhere in the region of 60% carbs,bread potatoes rice etc, 20 % protein meat dairy nuts etc, and 20% fruit and veg, % vary from place to place, but some thing in that order. You also need a lot of the things your told to avoid, like fat salt sugar etc. It's not having to much that's the trick, but that's true for all the food groups
Avoid heavily processed foods, avoid fad nonsense. Learn the body mechanics behind the kick (which varies widly - I can tell you how to do it in our system, but it might not match yours) and practice. Lots.
For kicking I think it is more about training your legs to do what you want them to.