Nothing gets in the way of good intentions like poor planning. You may have all the determination in the world to make a fresh start and eat healthy foods this week, but if you don't plan ahead, you may find yourself too busy to make something suitable.
When that happens, you'll wind up hungry and grabbing for anything you can find, even if it's a candy bar and soda. So, set yourself up for success by prepping meals for the week, and portioning out snacks and drinks that you can take on the go.
Also, make sure that you include protein and healthy fats in each portion because protein and fats will keep you fuller for longer and will keep your energy sustained much better than carbs will.