1.3kg (3.1 lbs) weight gain overnight... why?
I am doing a complete fast on alternate days and just having one big dinner on feast day as I find it easier to drop fat that way. I have been recording my progress in my journal and usually drop about a pound a day.
Anyhow, look at this weight fluctuation:
118.7kg (261.7 lbs) Fast day
120.1kg (264.8 lbs) Big salad, Thai green curry (no rice) ... had stomach ache so didn't have much of an appetite
119.2kg (262.8 lbs) Fast Day
LOL Be assured it's not fat gain
ADF way of eating is known to induce fluctuations of that kind (I believe you can see a nice graph on leangains.com One of the articles is comparing different intermittent fasting protocols and ADF had a funny looking - but not surprising - weight fluctuation).
What you gotta do if you monitor your weight, is to take data points every week (or every day if you like) in the same conditions (say every morning, after emptying your bladder and gut). After say 2-3 months, try to "make a fit", i.e. a smooth curve that will fit the trend the best (not the daily fluctuations, but the overall trend: flat line ? slow decrease ? slow increase ?). This will tell you whether you are truly losing weight.