I've believed I was "in tune with my body" at various times when I was eating far too little to maintain a healthy adult weight. If you consistently undereat then your appetite cues go all wonky.
Tbh I'm going to stop commenting on this thread because it's not good for me (because it makes me think, why bother maintaining a few pounds into the healthy weight range - why not be as thin as I like? Maybe I didn't look so ill after all? Maybe I didn't need to gain weight in the first place because we've lost sight of a healthy weight!)
But l will say the language around food and eating on this site can be utterly disordered, e.g. the thread from a couple of years ago about what BMI people feel slim at. And I know this from sad experience.