Well to me its pretty clear its your diet thats stopping you achieving
A margin of 300 calorie on lunch and potential for more variance on the evening meal add probably a few other variations in the day and we are talking 500 calorie differential a day. That added up over a week then you are talking a lb of potential fat loss a week may have been lost.
The difference between wanting and achieving is knowing the variables are right and how to manipulate them, your skinny frame is as a result of that variance. The body is literaly stripping the excess away fom the extremities but the last place it goes from in most guys is the very place we want it to go from our bellies and our love handles or as I prefer to call them our turbo packs :-).
I personaly go to the degrees of dietary manipulation when I cut, for want of a better word as I dont profess to be a body builder. I dont do static diets I adjust weekly up and down so that I always have a refeed in sight, for you the equivelant would be less activity one week and upping it a subsequent week. Many body building sites champion the daily calorie cycling approach personaly I find that way too cumbersome and complex to be of value.
Anyhow I digress.
Two things I would say: breakfast up that Mr to roughly 500 calories as you have been a long while without food. Go for an unprocessed cereal like oatmeal.
Try and go for a week of keeping that food intake consistent. Humans being creatures of habit mean we dont actualy eat that varied a diet so my best advice would be: for the next two weeks keep an honest account of what you eat. Use a tool like fitday at the end of the week and crunch those numbers up.
I think you will be shocked at the results.
Add a diet variance to a training variance and the body will struggle to release body fat, follow that with a day of potential excess the next thing you know thats glycogen going from the muscles and this will only compound the issue.
I may have to revisit the post tomorrow ha ha as its late now OH my god is it late! and I am going boss eyed!