Why have my friend and I gained weight - we used to be so skinny?

So I have been close friends with one girl since we were 13. We both have always been very slim. When she hit about 18/19 she was no longer slim and had definitely gained weight. For me everyone thought it was impossible that I would ever gain weight. When I hit about 20 (amount of food I ate had not changed) my hips widened and I became very full in the arms and my breasts and butt became more full. (And I was a STICK! Old school friends almost fell over when they realised it was me).I'm just wondering how this happened. I have always ate a lot of food so it's not because I ate more junk or consumed more calories. Why? (And fyi I don't mind the weight gain :p)

How to Lose Weight Fast at Home

Recommended Answer:

Your metabolism slows down as you reach adulthood. Adults generally are not able to eat as much food as teenagers without gaining weight. Change your eating habits in order to prevent weight gain. When I was in my early teens, I was always eating. Everyone marveled at me, since I looked like I was in great shape yet ate worse than anybody! But once I hit college and didn't change my eating habits, I ballooned out! It sucked, but I cut down on the amount I ate and adapted a healthier lifestyle. I'm now back to my old size, but this time I actually AM in great shape instead of just looking like it.

Other Answers:

• Well you have to take care of yourself when you're younger. All of this weight gain is the calories catching up to you. You can't always count on genetics to keep yourself skinny; hope this doesn't come across as rude. (: