You are referring to your HDL cholesterol, or "good" cholesterol level. You want it to be high, like 40-60 mg, or even higher than 60 is better.
The doc wants you to raise this number. Even losing 5 lb or 10 lbs would probably help, plus eating a healthy diet, that includes some meat.
You can google "raise HDL cholesterol" and find some tips to help.
http://heartdisease.about.com/cs/cholesterol/a/raiseHDL.htm
But what is wrong with me I don
Sometimes it's nothing you did; sometimes you're genetically prone to it. It's good that you caught it now.
If you can't get it to increase on your own, then I think there's meds you can take (can't think of the names right now).
It's not unheard of - my DH is only 27 and has the same problem. He's been losing a lot of weight and has changed his diet. He goes back in shortly for another blood test to see how much his numbers have changed.