Body Mass Index (BMI) and your surgery

Body Mass Index, or BMI, is a number that is calculated based on your height and your weight. It is a measure of obesity. There are dozens of free BMI calculators that you can easily find on the internet. When you plug in your height and your weight, you will get a number, and this number characterizes your degree of obesity:

  • Less than 18.5 = underweight
  • 5 – 24.9 = normal
  • 25 – 29.9 = overweight
  • 30 – 34.9 = obese
  • over 35 = extremely obese

Why Does Body Mass Index (BMI) Matter?

The importance of BMI is that is reflects your risk of obesity-related health problems such as diabetes, high blood pressure, and heart disease, among other conditions. This is why you should be aware of your own Body Mass Index and modify your diet and activity level if needed.

BMI is also very important in the surgical world since it also reflects surgical risk. It is extremely important when evaluating someone for an elective procedure like cosmetic surgery. This is because the level of obesity is related to the risk for complications during and after surgery, as well as predicting your body’s ability to heal from surgery. The data shows that people with a BMI above 30 are at increased risk for having a surgical complication.  These complications may include a negative reaction to anesthesia, breathing problems, heart attack, stroke, and blood clots. These can be serious and even fatal.  Additionally, we know that people with BMI over 30 are at increased risk for healing problems. This means that incisions may be slower to heal, there can be infections, and there can be an overall poorer cosmetic result. This is extremely important with procedures requiring long incisions such as tummy tucks and breast reductions.

What are the Body Mass Index (BMI) Recommendations for Surgery?

Based on this data, Board Certified Plastic Surgeons generally require that their patients have a BMI of 30 or below before proceeding with elective cosmetic surgery. This means that they are likely to decline to perform surgery on you if your Body Mass Index is above 30. This makes sense, since we certainly would never want to place you at risk, especially for an elective cosmetic procedure. Of course, if you needed life-saving surgery, the surgeon will perform the procedure no matter what your BMI is, and you would accept the added risk. But plastic surgery is different since it is not medically necessary and we try to minimize all risks as much as possible.

Criticism of Body Mass Index (BMI)

The criticism with Body Mass Index calculations is that it is imprecise and doesn’t always accurately reflect someone’s actual level of obesity. Critics argue that since it is so imprecise, it is not a good indicator for surgical risk level. This is definitely true.  A simple calculation using your height and weight does not take everything into consideration. BMI does not consider things like:

  • gender differences
  • bone mass
  • muscle mass
  • excess skin
  • fat distribution.

Men tend to have a higher BMI and this doesn’t necessarily mean that they are more obese. A muscular man may have minimal fat but a very high BMI. For example, NBA superstar Shaquille O’Neal stands 7’1” tall and 324 pounds. This makes his BMI 31.5 and in the obese range, but no one would consider this elite athlete to be too obese for surgery.  Also, patients who have lost a lot of weight will usually still carry significant excess skin. A person who has successfully lost 100 pounds and has no fat left on their body, may be carrying 20+ pounds of extra skin. Using a simple BMI calculator, they may have a BMI over 30 only because of the extra skin they are carrying around.  There is no Board Plastic Surgeon that would deny skin removal surgery in this case, even though the BMI is above the accepted limit of 30.

Also, the location of the excess fat is very important, and not considered in the BMI calculations. There is a difference between peripheral and central fat. Peripheral fat is excess fat in the extremities, like thighs and legs. Central fat is found in the abdomen, flanks, and back. Central fat is more dangerous since it has a higher correlation to obesity-related illnesses. Peripheral fat, however, is not as directly related to obesity risks. Basically, an apple shape is more dangerous than a pear shape. These are some of the things that must be considered when analyzing someone’s BMI and whether they are a safe surgical candidate.  A surgeon will probably be more willing to operate on someone with elevated BMI, if their excess fat is found in the legs.  However, if the excess fat is located in the core, such as the abdomen, the surgeon is likely to deny elective cosmetic surgery.

My Personal Philosophy

Body Mass Index is an important metric but it is not the end-all, be-all.  BMI is a guide and needs to be used together with other things like a surgeon’s experience and physical evaluation of the patient.  In my practice, I absolutely use Body Mass Index to help me decide if I am going to operate on a patient. When someone calls to schedule a consultation, we always ask for a current height and weight, allowing us to calculate their BMI.  Since I recognize that BMI is not totally accurate, I will allow people to be seen in consultation if their BMI is below 32. I will then evaluate them in person and decide if it is safe to perform elective cosmetic surgery the way they are. This involves evaluating things like bone structure, excess skin, fat distribution, and the desired procedure. I may tell the person that they need to lose a few more pounds, in order to get their BMI below 30, before I will agree to operate on them. I also find that I can offer a better cosmetic result when the BMI is closer to normal.

So, BMI is definitely something you should be aware of, since Board Certified Plastic Surgeons care about it.  You should google a BMI calculator and plug in your numbers to see what your specific BMI is.  This will help you be most prepared for your consultation and give you an idea whether or not you will be required to lose weight prior to your surgery. Your goal should be to have your BMI below 30 and as close to normal as you can. This will minimize your risk of surgical complications and also help to optimize your cosmetic result.

Schedule your Consultation

If you would like to see if you are right for the procedure you want, you can set up a consultation with Matthew Schulman M.D., New York City Board Certified Plastic Surgeon.