You can find various tools on the internet where you can type in different foods you eat during the day, and ultimately see how many calories that is, etc.
A personal trainer can make such a plan for you, but that is quite expensive imo, especially considering how much of a job that is.
I think it's best if you try it out yourself, see what works for you.
On that note, boxing training, for that matter would require of you to eat more, because of the amount of cardio.
You can calculate the amount of calories you need per day to maintain weight, when you find that number you subtract 300-1000 calories depending on your fat percentage. obviously the fatter you are, the more you want to subtract. Remember adjusting your calorie intake every time you lose 5-10lbs or so. these calculators can be found online.