Cravings: The first, most noticeable thing that happens to you is you start craving sugar since it's so addictive and your body isn't used to not have it. It's so bad to eat that even when you stop eating it, it gives you side effects. Like not eating it is a medication and has side effects. Headache, lethargy, nausea, a foggy mental state, and more. It's just a challenge to overcome, after the initial stage, you get used to it.