Technically, they think they know what those numbers mean. They know that people at risk for Diabetes and Heart Disease often have high cholesterol, etc...
My wife works in medicine and will agree with the numbers...the insurance companies follow suit because they are trying to minimize their risk of a payout.
Truthfully, everyone's body chemistry is different and depending on diet and exercise, and chemical action in your gut, you're going to get a totally different result. (Example, You can exercise a lot and your triglycerides will increase because more fat ends up in your bloodstream) Generally speaking though, diet and exercise commitments are the way to go. If you want to try taking a pill, consider fish oil supplements....take 2, 1200mg pills per day. If you don't buy the purified stuff, throw a bottle in the freezer and take them at night before bed. That will limit fishy burps, etc.