I’m afraid I don’t the scientific bit… I just know how my body responded at each stage of the diet! And I would never have relied on sugar or carbs for my energy levels… but good fats & proteins. Yes, right at the beginning my body needed to adjust with the lack of any carb, caffiene etc but at 4 weeks you should be well adjusted to that. So are you eating enough fat & protein? Coconut oil, olive oil, oily fish, avocado, organic eggs, organic chicken, greek yoghurt… are you having enough of each of these? Do uou
If you give us a run down of what you eat each day then maybe we’ll spot how you can adjust things to give you more energy?