I’ll start with a question: Do you think that sumo wrestlers are insulin resistant, or insulin sensitive?
Now keep in mind that sumo wrestlers are some of the fattest people on the planet, and that insulin resistance is one of the greatest determining factors of diabetes, metabolic syndrome, and a host of other degenerative diseases. Based on common perception that fat people are unhealthy, sumo wrestlers and their high body fat percentages should weigh in as highly insulin resistant, right?
Some exciting research has been presented over the past few years that might make you think twice about judging a person’s health based on their looks. Have you heard the terms, or ever been called “skinny-fat” or “big-boned?” These two terms refer to two relatively common states of health that are extremely deceptive. “Skinny-fat” is what scientists like to call “lean, metabolically obese”, while “big-boned” could be used to describe people that are “obese, metabolically lean.” Essentially, these terms refer to people that appear to be in one state of health on the outside, but inside are on the complete opposite side of the spectrum. You may appear lean (or skinny) on the outside, but be a complete mess on the inside (fat), or you may appear to be really obese on the outside but have incredibly efficient metabolic systems on the inside and be the epitome of health despite your big body composition (big-boned). There are plenty of people out there on both sides of the equation who don’t understand why it is, but some are able to eat whatever they want without seemingly gaining a pound, while others can exercise ‘til the cows come home and have a strict diet, but still carry around a hefty chunk of extra weight. Let’s take a deeper look at what’s going on and see if we can explain this paradox.
You may be asking yourself how it can be possible to look extremely obese but be perfectly metabolically fit on the inside. Mark Shigenaga, PhD and an expert on inflammation from Children’s Hospital Oakland Research Institute, says the key lies in the interaction between a person’s insulin sensitivity/resistance, and how that impacts the ratios of the types of fats they store in their body. The two types of fats that you want to pay attention to in this case are subcutaneous fat, which is stored below the skin, and visceral fat, which is stored amongst and around the various internal organs of the body. Subcutaneous fat, while not lending to a flattering appearance, is relatively harmless and even provides some benefits such as insulation and energy storage. Visceral fat on the other hand, is the type of fat that you want to avoid since it is not only hard to get rid of and multiplies itself quickly, but it is associated with almost every major health risk that we see too much of these days. As I’m sure you can see, a high ratio of visceral fat to subcutaneous fat wouldn’t be a good thing. In fact, usually this is a marker of some serious health problems that are already occurring or are about to if nothing changes. What determines which type of fat you store?
Fat is typically stored when you ingest more calories than your body can burn for energy or expend as waste. Whether you create that fat under your skin and between your muscles in a healthy manner, or start storing adipose fat deposits around your internal organs depends on many factors--but it is usually due to sources of inflammation and inefficient metabolic systems. Your cortisol receptors in your midsection could be responding to high amounts of external stress and store fat as a survival mechanism, or you could be really insulin resistant and store fat because of insufficient hormonal reactions to food. Shigenaga presents another source of inflammation: endotoxin. We ingest endotoxins with many of the foods we eat, particularly processed foods. Our gut bacteria mitigate much of this before it can cause problems, but if you have a particularly poor diet that is high in processed carbohydrates and bad fats, you could see large amounts of endotoxin flooding across the membranes of your intestinal walls. Your body reacts to this by creating large deposits of mesenteric (around your intestines) fat, which acts like a vacuum to suck up the endotoxin before it enters the bloodstream. If you put your body through these types of stress factors, it can lead to the storage of high amounts of adipose fat which you might not be able to see on the outside, which results in the “skinny-fat” look, or the “lean, metabolically obese” state.
On the flip side, Shigenaga points out that big-boned people display tendencies to create fat extremely quickly regardless of the amount of calories, and that this is metabolically effective and should be considered a good thing as long as your insulin sensitivity remains intact. Fast rising blood glucose (a response that is regulated by insulin) is a very bad thing and leads to storage of adipose fat. But many studies have shown that insulin sensitivity is negatively correlated with abdominal adiposity regardless of BMI scores. Basically this means that the more insulin sensitive you are, and the better your body can regulate your blood sugars, the less belly fat you will have. The more insulin resistant you are, the higher percentage of belly fat you will have.
Let’s reexamine the question I posed at the beginning of the article: do you think that sumo wrestlers are more insulin resistant (bad), or insulin sensitive (good)?
It turns out that sumo wrestlers display incredible insulin sensitivity, scoring much better than the average American despite their obese appearance. Their exercise and activity levels keep them extremely insulin sensitive, and while they eat massive amounts of calories to bulk up, they have extremely low ratios of adipose vs. subcutaneous fat because the visceral fat is burned while most of their fat is stored below their skin. They may not look healthy, but in fact they are far better metabolically than seems logical; you could say they are the model “big-boned” person. The same could be said of many athletes such as linemen in the NFL, or super heavyweight Olympic lifters.
Whether or not you have ever experienced being skinny-fat/big-boned or not, you should always remember that you can’t always judge a book by its cover.
Peter Bauman – Peter is a chef first and personal trainer second. With a background in the biological sciences and degree in psychology, Peter knows how to make food that tastes great and keeps you lean and healthy.