The Difference Between “Fat” and “Sick”
July 21, 2009, abcnews.com
“Critics Slam Overweight Surgeon General Pick,
Regina Benjamin” —By Susan Donaldson James
“Dr. Regina M. Benjamin, Obama’s pick for the next surgeon general, was hailed as a MacArthur Grant genius who had championed the poor at a medical clinic she set up in Katrina-ravaged Alabama. But the full-figured African-American nominee is also under fire for being overweight in a nation where 34 percent of all Americans aged 20 and over are obese.
Even some of the most reputable names in medicine chimed in. ‘I think it is an issue…’ said Dr. Marcia Angell, former editor of the New England Journal of Medicine…‘It tends to undermine her credibility…at a time when a lot of public health concern is about the national epidemic of obesity, having a surgeon general who is noticeably overweight raises questions in people’s minds.’”
Even Dr. Angell, an intelligent woman by any definition, doesn’t get it. Do you think Dr. Benjamin chose to be obese? Do you think she’s a glutton and a sloth given her talents, character, and track record? Is she overweight? Sure. Is she sick? Don’t bet on it.
Most people in the modern world do not want to be thought of as obese. Here’s a politically incorrect disclosure: my pediatric colleagues and I see Latino mothers who come to clinic with infants whose weights top the charts and tip the scales. And these women are worried, but in the opposite direction. “No come” (Spanish for “He doesn’t eat”), they moan. There is a racial/ethnic overlay to obesity. This is in part due to societal norms and what’s expected for your culture. For instance, some extremely poor countries have developed a set of cultural norms that equate obesity with affluence and desirability. Fatty foods, such as meat and dairy, were scarce in their native countries, and pitifully available only to the wealthy. Upon moving to America, immigrants from developing countries are suddenly immersed in a glut of rich energy-dense foods, and they overindulge as their insulin increases. Sometimes these cultural views persist throughout generations. The immigrants view their obese children as the epitome of health and an affirmation of their ability to provide for them. In their countries of origin, thin children were sickly and at risk of premature death. Unfortunately, they aren’t yet familiar with the fact that the opposite is true in America.
More political incorrectness: some teenage African American girls tip the scales at 300 pounds, but when you ask them if they think they’re obese, many will say, no, that they’re “thick” (which describes a girl who isn’t fat or skinny, but is well proportioned, and has meat on her bones and in all the right places). Many DJs still play Sir Mix A Lot’s song, “Baby Got Back,” “I like big butts and I cannot lie….” (Those of you with young children and not hip with modern tuneage may instead recognize this song as sung by the character Donkey in Shrek.) Then again, it’s long been known that, when polled, women consistently underestimate their weight. (Don’t worry ladies, you’re not alone in the exaggeration department; men consistently overestimate their height and other lengths as well.) Clearly obesity, like beauty, is in the eye of the beholder.
There seems to be a genetic component to this as well. Several studies have looked at how much fat must be present before signs of illness develop. And the results are striking, if not surprising. Caucasians start showing metabolic wear and tear at a BMI of around 30, which is why epidemiologists chose 30 as the obesity breakpoint. However, African Americans don’t show metabolic decompensation until a BMI of about 35, while Asians start to manifest disease at a BMI of around 25.1 On average, an African American woman can carry an extra 27 pounds over an Asian female (half of which is fat, half muscle), before she can expect some kind of negative impact from that extra weight.
Many of my patients will say to me, “As long as I feel all right, my weight’s not a problem.” They may very well be right. But for how long? Which brings us to an important precept about body weight. Whenever we step on the scale, we are measuring the sum of four different body compartments, only one of which is bad for us.
1. Bone. The more bone, the longer you live. When little old ladies fracture their hips, that’s their swan song. African Americans, to their benefit, have a greater bone density than do other races.
2. Muscle. More muscle is better for your health. Muscle takes up glucose. More exercise means more muscle, and more muscle means better insulin sensitivity. Arnold Schwarzenegger in his weightlifting days (anabolic steroids or not) had a BMI of 32, not because he was obese but because he was all muscle and had very little fat. When you’re building bone and muscle, you are providing a method for burning energy rather than storing it, which leads to improving your health regardless of your weight.
3. Subcutaneous (or “big butt”) fat. This makes up about 80 percent of our total body fat and is what gave Marilyn Monroe her hourglass figure. Believe it or not, more subcutaneous fat is better for your health. Several studies show that the size of the subcutaneous fat depot correlates with longevity. Little old ladies who don’t have much subcutaneous fat get sicker and die sooner, and not just from their hip fractures.
4. Visceral fat. The only compartment that is consistently bad for us is our visceral (aka abdominal, ectopic, or “big belly”) fat. This consists of fat in areas where it doesn’t belong, including fat inside your abdomen and inside your organs (e.g., liver and muscle). It makes up about 20 percent of our total body fat, or about 4–6 percent of our total body weight. Visceral fat is the fulcrum on which your health teeters.
The Scale Lies Even More Than You Do
Not all pounds are created equal. The scale lies—you were right all along!—at least in terms of your health and your lifespan. In fact, the majority of Americans now have a BMI of over 25, which puts them in the overweight category. Studies show that, on average, people with a BMI of 25–30 have the longest lifespan.2 So being overweight is good? Yes, all you Kate Moss wannabees—provided the weight is in the right place.
Do you ever wish that all the fat on your body would somehow miraculously disappear? That some talented plastic surgeon could painlessly remove every cubic centimeter of unwanted adipose? For free and with no lasting scars or cellulite? Come on, admit it. It’s a recurrent dream of virtually everyone on the planet. Even men.
Think again. What would life be like without any fat? Pretty damn miserable, and short to boot. Indeed, some unfortunate souls get to experience this firsthand. It’s called lipodystrophy and it’s one of the worst diseases known to humankind.3 It can be genetic or acquired as a complication of AIDS therapy. With it, you look weird, gaunt, and as if you’re circling the grave, which you are. When your body wants to store energy, there’s no place for it to go. So it goes to the only places it can—your liver, muscles, and blood vessels. The organs of people with lipodystrophy get filled with fat and they develop diabetes, hypertension (high blood pressure), and heart disease.
Bottom line, you need your fat. At least you need your subcutaneous or “big butt” fat, which provides a bucket for extra energy to keep you alive and healthy. With rare exceptions, your subcutaneous fat contributes very little to the development of chronic disease. Twenty percent of morbidly obese adults have completely normal metabolic status, no evidence of disease, and normal longevity. In fact, the smaller your subcutaneous fat compartment, the faster you die.
When it comes right down to it, it’s all about your middle. This whole obesity/health/longevity question centers on your abdominal, visceral, or “big belly” fat—at least statistically. All this hoopla about one body compartment, which constitutes only 4–6 percent of your total weight. But it translates into the difference of about fifteen years of life.4 Here, size really does matter; it means dying in your fifties of a heart attack or cancer versus living into your eighties or longer. Visceral fat depots are more metabolically active than subcutaneous fat depots, and they drive inflammation. Visceral fat causes insulin resistance, which in turn promotes diabetes, cancer, cardiovascular disease, dementia, and aging. While the populace is more worried about subcutaneous fat (because it’s unsightly), this fat is much less prone to being lost; in fact, it is rarely shed unless you go on a caloric restriction or starvation diet, which is rarely sustainable.
It’s the visceral fat that doctors care about, because it’s the visceral fat that kills you. When you lose weight on any diet, it’s the visceral fat that is lost first. It’s there for easy access for energy (see chapter 6), so it’s the first to go. And that’s good. But your body defends its subcutaneous fat, because that’s the fat that makes leptin, and your body (your brain) knows it’s good for you. And it’s even more specific than that. Your visceral fat is really just a proxy for your “ectopic,” or intra-organ, fat—the fat in your liver and muscles. This is the real killer. But it is too hard to measure without very specialized imaging techniques such as MRI or liver ultrasound. Chronic metabolic disease starts when fat deposits itself in organs such as muscles and especially the liver.
This fact is borne out in a recent study comparing BMI to percentage body fat by X-ray methods. It appears that many as 50 percent of women and 20 percent of men who are categorized as normal on the basis of their BMI are actually obese based on their carriage of visceral (bad) fat.5 The study’s author, Dr. Eric Braverman, called BMI the “Baloney-Mass Index,” because it gives a false sense of security to those who follow it. Indeed, Dr. Jimmy Bell of London, using MRI scans of the abdomen, realized that body size is irrelevant; it’s visceral fat that drives disease. He coined the expression “thin on the outside, fat on the inside,” or TOFI.6 Bottom line, it’s your visceral fat, in particular your liver fat, that counts.
How Do You Measure Visceral Fat?
Standing on a scale is great for determining your wrestling weight class, but it is woefully inadequate for just about any other purpose. It is particularly useless for discerning how healthy you are or whether you are at risk for metabolic disease and/or death. BMI is problematic because, as a measurement, it can’t distinguish between the four body compartments of bone, muscle, subcutaneous fat, and visceral fat. Doctors use BMI anyway because it works at a population level, but not necessarily for their individual patients. The reason is that, excluding African Americans (like Dr. Benjamin), who get five extra BMI points for free, and the 20 percent of obese subjects who are metabolically normal, if your BMI is over 30 you likely have a significant visceral fat component and some level of metabolic dysfunction.
Still, we need a better measure than BMI of where your body fat is located, how much, and what it means. The simplest and cheapest surrogate for determining your health status is your waist circumference, which correlates with morbidity and risk for death better than any other health parameter.7 This is arguably the most important piece of information in your entire health profile because it tells you about your visceral fat. A high waist circumference translates into the “apple” shape that tips physicians off to risk for diabetes, heart disease, stroke, and cancer. But physicians are loath to measure this in the office because you need a metal tape measure, the measurement is subject to error, different people do it differently (the two sanctioned methods use completely different body landmarks), it takes time and effort, and it means getting “up close and personal” with the patient. Furthermore, the doctor often doesn’t know what to do with the results except say, “You should really eat less and exercise more.”
A reasonable proxy is belt size. Greater than 40 inches for males and 35 inches for females is a likely indicator of visceral fat, which is correlated with insulin resistance and risk for metabolic disease in adults8 and in children.9 But you can imagine that people who wear their pants way below their beer belly might get the measurement wrong. As long as you have someone to help you, you might also try to measure your hip circumference. A waist-to-hip ratio of greater than 0.85 (in women) or 1.0 (in men) is another warning sign of insulin resistance, versus a waist-to-hip ratio of 0.8 or less, which suggests metabolic normalcy. Waist circumference is more complicated to measure and determine in children because it is dependent on sex, age, and race. While standards have been published, none of the childhood obesity guidelines from any of the medical societies currently advocate using waist circumference as a screen for metabolic disease.
Another simple method for determining your metabolic status is to look at the back of your neck, armpits, and knuckles. What you’re looking for is acanthosis nigricans, or a darkening, thickening, and ridging of the skin. Many people think this is dirt or, in the case of the neck, “ring around the collar,” but it’s actually excess insulin working on the skin (the epidermal growth factor receptor, to be exact). You might also see skin tags in these areas. Both of these are visible signs of insulin resistance and predict future risk for chronic metabolic disease. Every other method to find out your metabolic risk is expensive and requires blood drawing, specialized equipment, and professional data analysis.
Weight Loss Is the Wrong Approach and the Wrong Outcome
Any doctor will tell you that losing weight will improve your health, including me. And it’s a fact—except for two small problems: First, weight loss is next to impossible. Witness all the money wasted on weight-loss aids. And second, it’s only half-true. (See, even I lie!) When you go on a diet to lose weight, what are you losing? You lose some fat, but you’re actually losing more muscle, unless you exercise while you’re dieting in order to prevent the muscle loss. Remember, muscle is good for you. Even if you lost subcutaneous fat easily, it wouldn’t help your health. A group of obese women were studied before and after liposuction, which vacuums out subcutaneous fat only. Their metabolic status didn’t improve despite an average 20-pound weight loss.10 So aside from not being easy, losing weight is a bit of a crapshoot in terms of effectiveness.
And here’s the catch-22 of weight loss: thanks to the DEXA scan (an X-ray method of determining body composition), we know that when you lose subcutaneous fat (the fat underneath the skin) by dieting, you also lose an equal amount of muscle. Your percentage of fat stays the same. A decidedly good-news, bad-news deal.
So what should your doctor be telling you? No question, if you’re obese and you want to improve your health, you want to lose some fat. But the fat you want to lose is the visceral, or the ectopic (intra-organ, as in liver) fat. If you lose subcutaneous fat, too, that’s a bonus. Your doctor will tell you that losing even 5 percent of your body weight will be beneficial, which is true. Because that 5 percent is likely going to come from your visceral/ectopic/metabolically active fat. If you are obese, the National Institutes of Health recommends losing 7–10 percent of your body weight to reduce your risk of life-threatening illness.11 I agree; just make it your visceral fat—that’s the key to improving your individual health outcomes. Watch your waist circumference. If your pants fit better, then you are healthier. But if you think you’re going to be able to lose that big butt with any rational diet, think again. You might be able to do so—for a short time. But as you lose subcutaneous fat, and your leptin levels fall, your brain will sense starvation, and reduce the activity of your sympathetic nervous system (see chapter 4), reduce your energy expenditure, make you feel lousy, and activate your vagus nerve. Viva Las Vagus! That darn vagus will drive up your appetite, your insulin, and energy storage to replace what you lost. And you’re going to regain the visceral fat first. Screwed yet again.
So how can anyone do it? What’s rational? What’s effective? What strategy will improve your health? If I didn’t think this could be accomplished, I wouldn’t have bothered writing this book. The short answer is that it depends on how you got there in the first place. Because obesity isn’t one disease; it’s many. This isn’t a one-size-fits-all deal. Like anything in medicine, different problems require different approaches. As you saw in chapters 4–6, there are three reasons to eat—two insulin problems and one cortisol problem—and they all have different solutions. These solutions will be discussed in detail in chapters 17–19. The short answer is that to get your visceral fat down, you don’t necessarily need to lose weight. But you will have to do something different.