A couple of decades ago, obesity in America reached a level that experts labeled “epidemic.” Then it got worse. Americans went on a 20 year binge, and now 60% of us over 18 are overweight or obese. So if you’ve been trying to shed a few pounds lately, join the club.

Often some policymaker or other proposes a tax on junk food or fast food, and it can seem like an invasion of our lifestyle choices. But the truth is, we are already being penalized at the wallet for what we eat – more than many of us realize. Health insurance is a perfect example.

The increasing relationship between obesity and a large number of medical problems has health insurers reluctant to issue policies to heavier applicants. Obesity has proven ties to a wide array of medical conditions, from migraines, arthritis and menstrual woes to breast cancer, cardiovascular disease and diabetes. Obese policyholders can cost insurers possibly six to ten times as much in claims as a policyholder of average weight. Raising the premium of that obese policyholder six-to-ten fold is not an option. Instead, the obese are often refused coverage altogether. Meanwhile, the “merely overweight” policyholder is seeing dramatic increases in health insurance premiums.

When does our weight become an insurance issue? Probably sooner than you think. The industry has begun using the Body Mass Index (BMI) to determine how to categorize us by our weight. BMI is a mathematical computation that applies equally to men and women. Go here for an online BMI calculator. Otherwise, grab a pencil and we’ll walk you through it.

• Convert your height into inches. (cheat sheet: 4’=48”, 5’=60”, 6’=72”)
• Multiply those inches by .0254 to get your height in meters.
• Round the answer to an easily workable number.
• Multiply it by itself. For example if you got 1.72 you would multiply 1.72 x 1.72 to get 2.9584, which you’d then round to something like 2.96. This is now you Number A.
• Multiply your weight in pounds by .45359237 to determine what you weigh in kilograms.
• Again, round it to an easily-workable figure. This is now your Number B.
• Now divide Number B by Number A and you will get a number somewhere in the teens, twenties or thirties.

The results break out as follows:

BMI of 18.5 or under = Underweight
BMI of 18.5 – 24.9 = Normal
BMI of 25.0 to 29.9 = Overweight
BMI of 30 or above = Obese

If you need to lose weight, these results probably aren’t going to tell you something you don’t already know. But for those of you at the lower border of either the overweight or obese BMI categories, do yourself a favor: Lose enough weight to drop down a BMI category before applying for health insurance. The difference it will make can be crucial.

Health insurance consultant Kathy Thomas notes, “The sickest one percent of policyholders can comprise between 40 to 50 percent of all claims.” For this reason, if your BMI is outside the normal range, you may have some trouble getting health insurance. There are things you can do to fight back. For example, if you’re turned down because of your weight but you are otherwise in good health, ask your doctor to write a letter requesting you be reconsidered. Using an online health insurance agent like InsureMeOnline.com gives you the greatest access to the most health insurance policies at one time, which increases your likelihood of finding an affordable one that will take you on. Tend to your peripheral health issues, like smoking, high cholesterol or blood pressure. But the best thing you can do is join the millions of Americans that are successfully fighting the battle of the bulge.