Of course, always best to see the Dr. and work with a trainer. My mom is constantly on my case saying that I work out too much and am too skinny. My main reason for working out is that I get stressed and it burns off my stress. I literally just run it off so my head doesn't explode. It also helps me sleep a lot better so even when I am stressed it doesn't upset my sleep. I have osteoarthritis in my foot and nothing I've tried with multiple doctors has eased the pain as much as simply losing weight. I was in a cast from my toes to my knee for months and it did not help at all, but since I've been losing weight and keeping myself skinnier I only have problems with bad shoes and walking on sand, I no longer limp with every step. It's not just about how I look, but how I feel overall. For me it's a tradeoff. I don't mind literally working my ass off because it helps my foot (I run on an elliptical so there's no pounding on the bad joint) and for me, being skinny has proven to be a lot healthier overall. My blood work is as good as it can be and when I got those results back I was far, far more thrilled with my progress than any number on the scale or BMI chart. I'm not really caught up in all the emotional stuff about weight and apperance and whatnot. It is what it is and if I don't like something, I change it. Too many health problems on both sides of my family to think that if I just accept what I am without any work, I'll be OK later on. My mom thinks I'm crazy but my Dr. and my wellness director don't have any problems with how I work out or what I eat (and I still could eat better than I do).
No extreme is good, but I think in this country we often make a lot of excuses and have a jaded view of what is really healthy, what is overweight, what is underweight.