Ok so it seems like whenever I see someone complaining of sudden weight gain, they also just started fasting after coming from multiple meals per day. I think this might be at least partially explained by the actual time of day that you’re weighing yourself. The typical suggestion on the best time to weigh is in the morning after using the bathroom. This makes sense for someone who eats 2-3 meals per day because they just slept through their longest fast of the day. Theoretically that should be when their weight is the most stable.
When you add intentional fasting into the mix I think that changes for a lot of people. I generally fast through the day and eat one big meal in the evening, along with a few snacks a little later. It works out to something like an 18:6 or maybe 20:4 IF schedule. I’m by far my heaviest in the morning. That’s because I’m relatively close to my big meal still, even after sleeping through the night. I’m still carrying around a lot of the food I just ate, plus any water weight I might have put on due to sodium content. It’s just not a good time to get an accurate reading because it will vary a lot depending on what or how much I ate the night before. I find my best weigh in time is actually right before I break my fast in the evening. I will see a 6-7 lb difference in my weight from morning to evening, and it will be far more stable from one day to the next.
I would suggest that whenever it is that you break your fast, weigh right before that, and then do that consistently on future fasts to get an accurate picture of where your weight is going.
