Yes. I had theatre training and show by those two days during two day fast, managed to give myself a muscle fever. Lost a lot though. Now I'm going to bed with kids and sleep like a brick for 9 hours easy. It should change, but three weeks in keto/carnivore and I'm alert, but need my sleep. 

 The tiredness only lasts for a couple/few days, as your body switches from burning sugar (from crap processed food) to fat (from natural healthy steak, eggs, etc). Basically eat nothing that isn't in its original natural form.  

 I didn't eat processed foods before😀 Luckily my husband set a trend years ago, we eat only eggs and bacon for breakfast and such, so if something, I buried my snout into baked goods or a pot of soup.