Desperately having problems with energy balance for training......

I’ve got a little over a month until my university’s track team tryouts (I’m trying to walk on), but I am having an unbelievably tough time balancing my eating trying to keep excess weight off while trying to get in shape for this tryout. I’m a triple jumper mainly, so I don’t need a ton of speed endurance, but a lot of explosiveness through short sprints and plyos I guess. But I feel like in order to maintain my current body composition (so as to not be jumping with excess fat that’ll weigh me down), the amount of calories I take in does not allow me to complete my workouts very well at all.

Any tips? Perhaps some foods to steer clear of, and some to make sure to include, besides the normal nutritional guidelines we all follow as strictly as we can?

Oh, I should add, last year before I knew anything about nutrition, I had no problem having the energy to do hardcore workouts. Granted I was carryinga round a little more fat than I would’ve liked, but at least I was getting the workouts in, and pretty good quality ones.

One thing I notice different is, I used to eat a lot late in the day or at night, which is obviously a big no-no for “proper nutrition”. I’d eat a lot of later-evening spaghetti dinners, which seem to have given me plenty of fuel for future workouts in the day or two afterwards.