OK so here's the thing with eating healthy.
You should actually be eating 4-5 times a day. Its like your body is a stove and your energy is the fire. The food you eat is the fuel. If you just stoke the fire once a night with a big portion of wood, your fire will burn big for a short period then dwindle and die out before you stoke it big again.
If you continually throw a little wood on your fire throughout the day, you will keep your fire burning at a steady pace all day.
On the metabolism side of things, you are shoving all this food into your body once.. then starving it for 24 hours. Your body will remember this and it will start holding onto what food you give it so that it will have nutrients for the next 24 hours, since it knows it won't get anymore. Thus, your body will store more fat.
If you eat smaller portions throughout the whole day, your body will burn off more calories since it will know that it will be replenished soon. Thus, your body won't store all that fat and you will be more trim, more healthy, have more energy, etc.
This may be the missing key to your current program ;)