The headaches are from detoxing after few days they go away and I feel great, but I suffer headaches on a daily basis, but last time I did this diet after a few days while on this plan never had headaches again, as soon as I stopped headaches came back. Another reason I can't wait to restart, I love this diet, I've done slimming world, weight watchers but didn't lose much weight. We have to find a diet that we can follow and enjoy, I don't do the extreme version of this diet I do eat an evening meal. I couldn't live on just shakes, soups or a bar. I really love my eggs, chicken, fish, salad and veggies. I also eat oily fish and nuts. My losses are just has good as those on only 4 replacement meals. I also exercise 4 times per week. I only want to lose to stone so nothing to drastic for me.