Maybe a v small plate then, so you can only fit so much food on it, a saucer or a coaster 
You could do a week of skinny soups to give you a kickstart, or drop all refined carbs, it sounds awful but even if you just do it for a week or two I bet it will give you a boost.
But try a fast day, I often come in under 500 cal because I am lazy and in the week I only eat dinner, with the occasional small lunch. when it is warmer I have greek yog and berries but it is miserable this time of year and I want warm things so I swapped to broth which is only 4 cals a cup so essentially pointless, but it makes me feel all warm and satisfied!
I have no idea what we are having for dinner, my tummy says tacos but my brain says no!