How Can Birth Control Pills Can Affect Weight Loss?

The first time I went on the pill I was 16, starting 6th form at school. Suddenly we were allowed out into town at lunchtime and I would go buy massive pork pies, a couple of bags of crisps, coke and chocolate. I blamed the pill.
I went on the same pill 3 years later and then went through a breakup which resulted in me losing my appetite and loads of weight.
Now I'm on Yasmin and the only difference I've seen has been my boobs growing a size, which probably adds a little on the scale but I also started eating boyfriend portions for a while.

The way i see it, if you go on the pill its often because of a new boyfriend, which means going out to eateries more and eating bigger portions, perhaps more often too. Coincidence.

Personally, I never gained any weight while starting the pill however I gained 10 pounds as soon as I went off the pill (however I'm pretty sure that's more due to the fact I have PCOS...)

I think that it's not necessarily the pill causing weight gain in some women but how our bodies react. Some people may get a bigger appetite or more cravings which will cause them to eat more while they're on the pill which makes them gain weight.