In order to stick rigidly to the plan, you'll need to prepare all your food, which means packed lunches (and in some cases, breakfasts and dinners, too). You'll probably be bulk-cooking some meals too, so make sure your kitchen cupboards are well-stocked with Tupperware, sandwich boxes, and food containers. The most useful ones I've found are Systema Salad Boxes (£6), which have built-in compartments and tiny tubs for dressing, and Noodle Bowls (£6), which are great for anything saucy that needs reheating. A good quality reusable water bottle with measurements marked on the side is also a good investment, as you'll be drinking a lot of water, and this will help you keep track.