I know everyone is advocated counting ever smidgeon of food that passes your lips, and yea, thats ideal...but it isn't always practical. Do it if you can, but don't let it discourage you if you just can't swing it.
Prepackaged food is awesome in terms of convenience, but often not so much for health. I too struggle with the 'easy meal' problem. Fruits, veggies, Go-gurt is great to freeze and take along for the day if you can get over the "I'm slurping yogurt from a plastic tube" aspect.