Rule number 1. Don't buy processed food, sugary snacks, and crisps.
Rule number 2. Plan. Make sure you select a few healthy options from this post.
Rule number 3. Set aside a few hours on Sunday to get your weekly snacks ready.
Rule number 4. Calories don't matter as much as the quality of what you eat. And I don't necessarily mean organic. Make sure you eat whole foods as much as possible. Whole grains, legumes, fresh fruit and vegetables, nuts.