You may be having difficulty reading his body language because you may be dealing with a man who is at a crossroads.
In constantly staring at you from a distance when he sees you and consequently smiling, he is showing signs of romantic interest.
The same can be said whenever he shares his food with you as his entire face smiles to the point where it wrinkles up.
Sharing food is often a telltale sign that a person is trying to bond with you and create a more relaxed atmosphere.
This is often a precursor that leads to more physical proximity and touching.
Again, these are all strong signs of romantic interest.
However, you may be having a difficult time trying to unravel his behavior because he is actually not sure about whether he wants to pursue anything romantic with you or anyone else at this time.
When he told you that he is not ready to date during a conversation that you had with him about relationships, he was trying to save himself from any expectations that his confusing body language may have embedded in you.
In essence, he volunteered that information without any prompting from you because he may be trying to keep himself under control and avoid the possibility of emotional complications that may arise between the both of you.
It is almost as though he is trying to tell himself to slow down.
He may still feel that he has yet to completely get over an ex.
However, he is at a crossroads with this sentiment.
There are times when he feels that he may have actually gotten over that ex.
Those are the times when you have noticed his body language become a lot more receptive to you.
This is also when he has felt more confident in asking you about what your plans were for the weekend.
However, those moments may soon be followed up by doubt and anxiety based on the emotions that he may still be experiencing from a previous relationship.
As a result, he chooses not to approach you or ask you out.
As long as his emotions remain at a crossroads, you may keep experiencing this kind of confusing body language from him.