Lots of water!!! Water helps you feel full, also black coffee doesn’t break your fast if you have low energy! Another thing that helps when I’m feeling fatigued is adding a 1/2 tsp or so of salt in your water, replenishes your electrolytes.
Also another thing- I’m really bad at tracking calories so I’ve kind of set new guidelines for my self that make it a bit easier. Instead, I just try to make most of my meals using raw ingredients! For example, making a dough instead of using an extremely processed pre-made one. Raw sugar or honey instead of pumps of syrup. I feel better knowing I’m eating less processed foods. I did this for a month or so and lost nearly 25 pounds. With the holidays I fell off a bit but am starting again now. I think 50 is attainable if you’re strict with your fasts! Good luck you got this!