I've just returned to 5:2 after falling off the wagon. I'm now on non fast days eating to my goal TDEE ( that's been difficult but I've got there) . I just tried my first fast day yesterday I had a 250 calorie omlette at 9.30 and went to work . I didn't feel hungry as such but I just couldn't concentrate had a major dip in energy so I ended up getting myself a sandwich which after I felt fine. I have decided to fast today but I think I'll eat lunch and dinner as not too fussed about breakfast any advice ?