Well...in my case, I lost over a quarter of my body weight (about 40 lbs.) last year from some as-yet undiagnosed medical condition. Just couldn't eat more than a few bites without feeling too full to eat anymore.

But the body needs food, whether or not it wants to admit it. I've developed a technique of eating a lot of soup or smoothies, since I can eat more at once (and sometimes even a milkshake to get more calories), and also of eating tiny four-bite meals every hour or so to get enough nutrition. So at least I'm not losing weight at the rate I was.

In my case, I exercise a lot and need the energy from food to do that even if my body wants to reject the food. It sounds like you may have initially lost your appetite because of something else, but you've now trained your body not to want food. But it does need it.