Weight fluctuations

[guest2013]

I'm sure its been done to death but how much can does your weight fluctuate in a week.
For 3 weeks, I have been eating under 1000 cals 4 days a week including one day of complete fast (only water) and then eating what I like for 3 days over fri night to Sunday.
Every week, I have started at the top end of a stone and ended at the bottom end, with a fluctuation of 9lb!! But after every weekend I have been right back where I started
Surely I would lose weight doing this though?? I can't be eating enough on 2.5 days to compensate??
And what do I actually weigh with such a large fluctuation?!

It sounds like you are undoing all of your hard work through the week, by not tracking over the weekend. Have you calculated how many calories you are consuming Fri to Sun? You are probably losing water weight while dieting / fasting, which will then go back on as soon as you are eating again.

Is there a particular reason why you are eating less than 1000 calories 4 days a week plus a fast day? You are malnourishing yourself? This will cause your body to cling on to anything it can when you binge. This sounds like a super unhealthy diet.

I agree this is terribly unhealthy, to lose weight you'd be better off working out your total daily calories required (BMR +activity levels) and have a 500 cal deficit every day across the week, track every day and don't binge at the weekends, because if you're limiting yourself to less than 1000 during the week, then you are indeed bingeing at the weekend.

This calculator will tell you how many calories you need to maintain your current weight (TDEE). As Butternut says, just eat 500 cal a day less than that to lose weight in a realistic, sustainable way.

Sounds like utter misery to me. Why not try to balance out your daily calories at 1200 or 1300 then add a few more in at weekends and don't count your exercise. Don't count fruit or veg at all. That works for my weight maintenance. Every so often you can even add in a load of cake and the scales don't budge. For weight loss keep to 1200 daily with the odd break out

1200 is still really low, I think you'd be surprised how many calories you actually need, so you do any exercise at the moment? Are you active during the day? Do you have much weight to lose?