Switch from Processed Foods to Unprocessed, Whole Foods

Replacing processed foods with homemade meals made from scratch using whole ingredients is an ideal and important way to ensure optimal nutrition. This will automatically cut out the vast majority of refined sugars, processed fructose, preservatives, dyes, other nasty chemicals, and many addictive ingredients from your diet. This will allow your body to depend less on sugar and more on fat as its primary fuel—provided you eat enough healthy fat, that is. As a result, you will no longer crave sugar to keep you going.
Please keep in mind that proper nutrition becomes even more important when you're fasting and/or cutting calories, so you really want to address your food choices before you try any form of fasting. The key elements for a healthy diet that can help kick your junk food cravings to the curb are the following. For a comprehensive guide, please see my free optimized nutrition plan:

• Avoiding refined sugar, processed fructose, grains, and processed foods
• Eating a healthful diet of whole foods, ideally organic, and replacing the carbs you eliminate with:
• As much high-quality healthful fat as you want (saturated and monounsaturated). Many would benefit from getting as much as 50-85 percent of their daily calories from healthy fats. While this may sound like a lot, consider that, in terms of volume, the largest portion of your plate would be vegetables, since they contain so few calories. Fat, on the other hand, tends to be very high in calories. For example, just one tablespoon of coconut oil is about 130 calories—all of it from healthful fat. Good sources include coconut and coconut oil, avocados, butter, nuts, and animal fats. Also take a high-quality source of animal-based omega-3 fat, such as krill oil
• Large amounts of high-quality organic locally grown vegetables and ideally sprouts grown at your home
• Low-to-moderate amount of high-quality protein (think organically raised, pastured animals or eggs)