satisfying lunch for only 300 cals...really?

So i know some things are definetly better for you than others, but today I got home for lunch and planned on eating the left over spaghetti from dinner last night only to find it all gone:(. so I decided to make myself an omlette, it came out scrambled eggs but it was intended to be an omlette. about 2 ounces of ham, 0.5 ounce chopped onion, 1 ounce chopped mushroom, 1 ounce shredded cheddar, and 1/2 cup egg beatters. came out to just under 300 cals and still not really that hungry 3 hours later. wow, didn't expect that.