The up day down day diet was a popular IF method a few years ago. I like the principle but hate fasting so thought I'd try modifying it to a gentler version. I can lose 1lb a week on 1500 calories a day so I decided on alternating days of 1000 and 2000. The 1000 calorie days are ok, I feel hungry but not ravenous. And I happily cope with them if I know that tomorrow I can have a big carby breakfast, a few biscuits, wine with dinner etc. Only been 2 weeks but have lost 3lb. Early days but first impression is that it's more sustainable than anything I've tried before.