This doesn’t happen often, but sometimes my eating window is throw off because of scheduling conflicts, or an outing. For example on a 18:6 fast, I may eat earlier in the day, but then also have a late dinner, so then my eating window is 8-10 hours instead of the usual 6 hours. But I still fast the 18 hours overnight until the next day.
So I’m just wondering if I need to strictly stick to the 6 hour eating window? And will this affect my fast/results?
It will be fine.
A big part of the fasting lifestyle is making it work for you in the real world. When I had something unusual come up and my fasting window got reduced, I’d try to extend my fasts in the following day or days to make up for it. Not that it’s necessary, but it kept me from slipping into old habits. That’s the bigger issue.
The 18 consecutive hours of fasting is the more important part. If you lengthen one eating period by 2 hours, and therefore shift the start of your fast 2 hours later, and therefore shift the start of your next eating period 2 hours later, then you’re fine — you still fasted 18 hours. You might shorten that next eating period to get back on your regular schedule.
But even if you have to shorten one fast to get back on schedule — like you can’t shift the start of your next eating period, so you end up fasting only 16 hours instead of 18 — it’s not a huge deal as long as it’s not happening very often.