whats helped me a lot is using the 1 ingredient rule. I try to stay clear of anything in the grocery store that contains more then one ingredient... I make everything at home myself from scratch and freeze extras if necessary. This keeps me from putting a lot of preservatives and extra sugars and salt. Saves me so much time not having to read every label as I go through and my meals turn out bright and colorful!!
I also put a lot of my seeds and nuts in my homemade whole wheat breads and take them with me in the morning with a piece of fruit and my water. Last me well until lunch!!