3 years into PP, I intermittent fast on the daily. Grew up my whole life eating 3 square meals a day, switched over this past year. I have lost weight (fat) and feel better/more mentally alert. I was probably only 5-10lbs overweight, but that was a change for me. When I was younger I ate whatever and was always thin. Call it slowing metabolism/aging. I am a huge proponent of intermittent fasting and it just makes my PP day easier because I can work through until dinnertime without eating. I should also mention that I wake up before work and do 15-20 minutes of weight lifting in my garage before riding my bicycle 4 miles to the hospital. My point being that I was doing some exercise daily, but my nutritional discipline was seriously weak.
Now, I not only eat less, but I actually pay more attention to how different types of food are affecting me.
Sounds like your problem is more related to trying to figure out foods that you can munch on during/between cases? Some of my partners are into dried berries and nuts (not salted: you will get too thirsty), there are always some protein bar proponents. Chugging a protein shake is quick, but then you will have a full bladder during the case. Cheese sticks are another idea of something easy to throw in the bag, they can easily be eaten wherever/whenever.