I didn't even know you could eat food during combat
As for clerics, as long as you can maintain concentration, then spirit guardians is great *and* you can upcast it to make it even better. I use it quite a bit in table top and my cleric can definitely hold his own in a fight - 5E seems about what I'd expect for a cleric (3.5E and PF they def became quite a bit more powerful). I hope they include many more 5E domains than the few that are in now. I was really hoping that EA would include level 5, just so we could see how more powerful class abilituies work, but we'll have to wait.