How do you know that you are a "healthy" weight?

I use healthy loosly because it has no coratlation to your weight. I found out today that I weight 248 pounds. I stand 6'1 but I am toatlly healthy. I am trying to lose weight to be thin again because of vanity. Is that healthy? So how would you know when you got to a healthy weight?

bmi of 20 is as low as you should go x

It's possible to be 248lbs, 6'1" tall and healthy.  It's also possible to smoke 20 cigarettes a day, drink a lot of wine, sit on your backside & eat fatty food all day.... and be healthy.  For the time being....   If you're under 40 and you do all these things your vital signs will be OK & you'll feel fine but eventually, they will catch up with you..

That's why a BMI of 20 to 25 is recommended.  Not for short-term health or reasons of vanity but for long-term health.  There are some people with a high BMI who are professional athletes and stacked with muscles.... but they're generally in the minority.  The average person with a BMI over 30 (the cut-off for 'obese') is significantly more likely to experience health problems such as heart-disease, cancer, high blood pressure & Type II Diabetes in mid to later life. 

So there is a correlation between 'weight' and 'health'.

Hm...I'm pretty sure that weight IS correlated to health...at least, risks for cardiovascular and metabolic disease, and obesity is a risk factor for cancer as well.