Wow 4,000 to 5,000 calories. That's a lot. We eat half of that. In the past I had issues with eating everything too since I can't throw food away... but then I learned to keep small leftovers in the fridge as a snack or use it the day after in another dish. Good luck with the fast! I'm sure you can do it. We did a 3-day coconut water fast not so long ago. Though I never felt really hungry, on day 2-3 mornings were so clear, energized, and I got a lot of work done, but afternoons brain capacity went down a lot. Luckily we work from home and could take afternoons off.