Just wanted some opinions really.

At the moment if I calculate my BMI I come up as underweight (it's 17.5). I am pretty skinny but eat what I think is a healthy diet and my mum and sister are a similar size, and don't think I look unhealthy. However, the NHS website seems to think I need to worry about it and I was wondering whether anyone's got any advice. Should I be trying to gain the extra half a stone to hit a 'healthy' weight and if so...

  • What do I eat to gain weight healthily whilst also running 3 times a week (I guess I'm averaging about 20 miles a week at the moment)?
  • Will gaining weight make me slower? - I feel like being little means I've got less to lug uphill, and less to bang down through my knees coming down, but this is probably psychological.
  • Will not gaining weight make me injury prone? Have read that underweight female runners are specially prone to stress fractures.

I'd like to be able to run as far and fast as my body's able. It's also not impossible that I'll be thinking about kids in the not-too-distant future and I wonder whether pregnancy might take less out of me if I've a bit more meat on my bones.