Sleep

[Yatzydog]

Simple question: how does fasting (specifically 5:2) affect your sleep?

I fancy the idea of fasting for health reasons. But have always been apprehensive because lack of food really affects my sleep. Basically I can't sleep if I have a less than full stomach. (In fact, this has become a whole issue in itself, but that is another story.)

Last night I clearly did not eat enough during the day. Thought I will see if I can ignore it and get through to the morning. God it destroyed my sleep and hence has destroyed me today.

I got used to it. I think I read somewhere that your body gets better sleep when you are not digesting food. At first I napped to avoid the hunger but now I’m used to only eating between 12 and 8

I don’t think it’s good to go to bed with a full stomach even if you’re not fasting. But as previous OP says you get used to it and your body should start to adapt. I never feel hungry after my main meal anymore whereas before fasting I was always after little snacks after eating dinner.

Fasting can increase your cortisol levels, particularly in the early stages, which in turn can impact sleep. I used to fast a lot, but with the advent of perimenopause had to stop as, together, it was impacting my sleep too much.

I have done 36 hour fasts a few times, and going to sleep / staying asleep having fasted for 24+ hours was tricky because although at that point I didn't feel hungry (that comes and goes earlier but is not really an issue at 24 hours plus) I felt quite "wired" and full of energy and not tired - I often did my 36 hour fasts when the last 12 hours were an overnight on site on call at work because I couldn't sleep well there anyway and had to get up in the night, so it wasn't totally unhelpful to be full of energy, but I always crashed hard and had to sleep the next day during the day or go to bed early and sleep for 10+ hours the next night instead of my usual 7.5 ish.

Since changing working pattern to days I slipped to only fasting 14-16 hours (which isn't enough for me) and I've just recently got back to mostly 18-20 hours, which is best for me. I feel much better when I do 20:4 and my sleep is excellent compared to 14:10. I think ypu have to find what works for you, but I fall asleep quickly and sleep through solidly when doing 20:4, which is quite something at my age (menopause messed up my sleep, getting back to fasting and HRT fixed it).

Sorry, I see you were asking about 5:2 not about timed eating really, so my answer isn't that relevant.

As you say you need a full stomach to sleep and want to do 5:2 you could do the 500 calorie meal on your fast days (I believe the original 5:2 includes that). Instead of spreading the 500 calories through the day (which will make you hungrier) research some very filling 50 calorie my eals to eat before bed. The classic mums net joke about the "massive salad" comes to mind 😂 But you could genuinely have a massive salad - make a huge family sized salad serving bowl full of lettuce, tomato, cucumber, radishes etc. with a bit of olive oil, balsamic, salt and pepper and eat the entire thing with a big piece of salmon or a skinless chicken breast or a family sized portion of cottage cheese - that'd still be within 500 calories and you wouldn't be hungry going to bed. You could alternate the garden salad with steamed vegetables - literally as much as you can eat as long as you don't add lashings of butter or sauces, and again eat with fish or a chicken breast.0

500 calories not 50!