The very, very simple reason is that we eat too much. And/or don't exercise enough.
See? Simple. Very, very simple, even.
I will go into some of the rather complex science of weight gain and loss in a companion piece. The issue here is to discuss some of the not-so-obvious reasons why fat is bad. There are a lot. Enough for several posts, at least. We all know that being fat is the root cause of Type II Diabetes, complicates high blood pressure and high cholesterol and leads to heart attacks. But fat almost literally affects every system of the body and has profound impact on the practice of medicine apart from the health effects. Did you know about . . .
The Body Mass Index. More commonly known as the BMI. While not a perfect tool, the BMI is a surprisingly accurate predictor of weight related morbidity ("ill health"). We talk about folks with a BMI of 18-25 as normal, greater than 25 as being "overweight," over 30 as "obese" and over 40 as "morbidly obese." Some may be surprised to know that these numbers are not arbitrary.
If one plots all causes of morbidity against BMI one gets a rather "J" shaped curve. The broadest, flattest part of the base represents the least morbidity and corresponds to the 18-25 range. Below 18 the curve raises as we get into malnutrition and starvation territory. On the other side of the curve there is a series of inflection points at or around 25, 30 and 40, each steeper than the one before it. Not surprisingly the curve above 40 is the steepest on the graph. The higher your BMI the higher your chances of having serious health issues.
The moral of the story is that your BMI is directly related to your risk of all disease.
Ultrasound imaging. Ultrasound is a wonderful imaging modality. It requires a very low energy form with no known direct health consequences and is harmless to developing fetuses. It can take real-time moving images. It can easily show rates of blood flow in the vessels. And ultrasound devices are now about the size of a laptop computer, relatively cheap and don't require a lead-shielded room making them readily accessible to office providers or even traveling health care workers.
However, the problem with ultrasound is also that it is very low energy. Which means it has a limited ability to penetrate tissue. It can't see through bone at all, and even softer tissues attenuate it quickly. Tissues like fat. Ultrasound is of limited use on obese people. Two inches of adipose tissue and what's underneath it is essentially static.
So, what's the option? Either something more invasive, or relying on CT (a great tool, but involving exposure to radiation). I recently had a patient who weighed nearly 400 pounds and was suffering from heart failure (essentially caused by his weight). We needed to get an echocardiogram. But the TTE (TransThoracic Echocardiogram), where we "look" directly through the chest wall from the outside, which could give us the information we needed was not effective because of his size. The alternative? A TEE (TransEsophageal Echo), a procedure where the transducer is slid down the esophagus to look at the heart from behind. Obesity forced us to use a more invasive and dangerous procedure.
Palpation: One of the fundamentals of physical exam is actually feeling the patient. The doctor doesn't mash on your stomach for fun - she's trying to feel if there's something in there that there shouldn't be. A huge inflamed liver, maybe, or an aneurysm of the abdominal aorta. But on a obese person palpation is of limited use. Imagine feeling for your toes through a pillow versus a sock.
One of the least favorite aspect of the pelvic exam for women is the "bimanual exam" - one hand in the vagina, one on the abdomen. We feel for the dimensions of the uterus by pressing from side to center on the abdomen and feeling for motion on the cervix. This doesn't work well on obese women. We feel for the ovaries by stroking down the abdomen and trying to "catch" them between our two hands. It's tough even on thin women since a normal ovary is only about 2 cm in diameter. Nearly impossible on heavy women. What we hope to (never) find is a mass. I shudder to think how much larger an ovarian cancer would have to be for me to feel it in a 250 pound woman versus a 150 pound one. And care to take any guesses on the relationship between size of a tumor and the prognosis? It's not positive.
Childbirth: I recently completed ALSO - Advanced Lifesaving Skills for Obstetrics. We talked about shoulder dystocia, a potentially life threatening situation where the infants shoulders get stuck behind the pubic bone. One of the later maneuvers to try is to have the mother get on her hands and knees. (This has the potential to shift the infant and possibly dislodge it). But since shoulder dystocia occurs late in the labor process it is not unusual for a mother to be too physically exhausted to do this. So you have to find enough nurses or family members to hold her up. One of the instructors told a really scary story about what it took to get a 250 pound mother on her hands and knees. Four nurses. Nurses who had to be pulled away from their own laboring patients.
To make matters worse, obese women tend to gain more weight during pregnancy, which translates to larger babies. And big babies are the primary cause of shoulder dystocia.
I have also spoken with doctors and nurses who are convinced that obese women have more difficulty delivering. The best reason I've heard from this is that when obese women push there is too much tissue and it tend to dissipate the force of the push.
I've got more. And am collecting new ones all the time. I'll revisit this topic on a fairly regular basis to expand my list.
I have also spoken with doctors and nurses who are convinced that obese women have more difficulty delivering. The best reason I've heard from this is that when obese women push there is too much tissue and it tend to dissipate the force of the push.
I've got more. And am collecting new ones all the time. I'll revisit this topic on a fairly regular basis to expand my list.
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