Stay on the perimeter of the supermarket (fruits/veggies/meats/milk/eggs) aside from going into the center for staples like bread, rice, oats, and spices.
Go to the gym and do Bill Starr's Linear/Madcow 5x5. (
http://forum.bodybuilding.com/showth...0023931&page=1 )
You really can't get any simpler than that and you'll have the body of a pro athlete in under 2 years.
e: the reason you are tired and moody is because you are starving yourself, and your body will panic and start storing everything you eat as soon as you get off because it's pretty sure you're trying to starve yourself too
e2: this works both ways, if you're fat and trying to get in shape, or if you're skinny and trying to put on muscle mass