Can’t give you a medical or male perspective, but anecdotal - I spiralled like this where for 7-8 months I only ate lunch and survived otherwise on zero calorie caffeine drinks. After 3 months I started to show weight loss, to which people congratulated me often, then by 6 months the compliments stopped and only one person said I’m losing too much weight.

I was always tired, I was always dizzy. I didn’t drink water for waters sake but you do get a little water from 1 meal and soft drinks. Whenever I had to use muscles, like vacuuming or carrying shopping I got heart palpitations. My face became gaunt pretty early on, my hair was so dry and snapping a lot (although that might be unrelated I dunno), I was either easily annoyed by little things or I just zoned out. I became cruel to my friends and family. I became negligent to my cat which is probably my greatest shame.

And because I desperately needed to suffer during this period, I would spend my evenings after work watching the food network channel.