It's not dangerous to go a few days without food, but extremely dangerous to go a few days without water. Water is everything. People lost in the desert spend days soaking their clothes in pee to not lose a lot of water. They don't die of hunger. They die of extreme thirst and dehydration. Hydration is key. As is replacing electrolytes if you do vigorous exercise and not being in places that cause the body to rapidly overheat. People who take MDxx (MDA, MDMA, MDEA, MDPR, MDPH, ect.) take MDxx once a month and usually spend a few days without eating afterward, but always properly hydrate and stay cool. Go for it, but don't dehydrate yourself. Don't overhydrate either. You could try drinking water and meditate blindfolded and eat only dandelions for a few days. Dandelions have most of the nutrition you need. Dandelions are everywhere. Also, lots of plant based food contains plenty of water, so drinking 8 literal glasses of water is unnesesary.
Dehydration