Weight

Eat more than you used to. But dont eat fatty foods. Just cause you're not putting weight on, fatty foods will still be bad for you. Eat healthily.

Anorexia is a mental illness, being skinny doesn't mean your anorexic.

BMI CALCULATOR

That should give you an idea on whether your at a healthy weight or not.

I would like to know as well because I have got quite alot of muscle but extra weight always helps.

You can put on weight by eating more high protein foods. I used to be "skinny-ish" even though I ate loads of chocolate/cakes & have a huge appetite. I've changed my diet & started going to the gym & doing weights. 1 tin of tuna has 25grams of protein in, and I eat 2 of these daily. Chicken is also extremely high in protein, something like 26.1 grams of protein per chicken breast / 100 grams of chicken. Although it isn't nice to do, eating 1tbsp of peanut butter contains roughly 4.6grams of protein. I've cut out most of the chocolate/cake but have read that it's alright to treat yourself every now & then. Other meats like Ham, Steak & Beef have high protein content so make sure you eat plenty of meat. You can also get protein shakes, some of which have upto 50grams of protein per shake. Mine contains 43.6grams of protein & I used to drink it with milk after a workout, but read that it's better to drink with water as it gets in your system quicker. Milk is also extremely good protein wise & I have anywhere upto 4 pints of it a day.