day after first fast day and feel terrible! Is this normal?

[Gilbertus]

Did my first 500cal day yesterday and had trouble getting off to sleep but otherwise it was fine. This morning I didn't eat until 9 (had been up since 7) but I still feel crappy - headaches, really tired, no energy. Is this normal and does it pass?

I had my first fast yesterday and oddly I feel fine . I've not eaten yet today maybe it will hit me then.

Drink plenty of water! Your body may have burned fat as an alternative source of energy to food - this is not as efficient (think burning coal instead of gas) and leaves waste products behind that must be excreted by the kidneys.

Water helps this process.

Hiya, I had my first FD on Wed and doing another one today. Have been to the gym mon-Thursday and did 2 hours each morning. Yesterday morning - after FD - felt so tired and energyless, had to have a banana before my class but still felt lacking in energy. But it could either be down to the amount of exercise I've had or the FD. Will be interesting to see how I feel tomorrow after second FD but with no gym this morning.

Felt better by about 12. Don't think I could do a fast day, normal day, fast day just yet. Will try Thursday and Monday to give more of a rest in between.

Yes it is normal when you first start. After a couple of weeks your body will get used to it and you will be fine.