The More You Weigh, the More You Pay

Premiums also varied significantly among insurers for a person with the same weight, ranging from $395 to $520 per year for someone weighing 180 pounds to $1,030 to $1,685 per year for someone weighing 270 pounds.

Insurance companies use what is known as a height-to-weight ratio to determine what they'll charge you, and different companies use different ones. So it can pay to shop around.

The good news is that if you purchase a level-premium policy, like the 20-year term I used in my example, your rate is locked in. So if you gain weight as you age, the insurance company can't charge you more.

The flip side is that if you lose weight -- and keep it off -- you can shop around for a new policy at a lower rate and cancel your current policy.

Nearly as important as your health is the health of the insurance company you rely on. You want to buy from a company that will be around in 20 or 30 years to pay your claim. There are about 150 companies that sell life insurance to individuals in the U.S. You can find out the financial strength of your company or any that you may be considering here.

There are many regional companies that are financially sound, but the strongest companies that offer life insurance nationwide are listed here.