Why the Kind of Body Fat You Carry Matters

Why the Kind of Body Fat You Carry Matters FinalAll fats are not created equal. We know this because we’re constantly correcting people who get it wrong. There are good fats and bad fats and really really bad fats and fats that are conditionally good or bad. Butter isn’t corn oil isn’t fish oil isn’t monounsaturated fat isn’t palmitoleic fat isn’t linoleic acid. Sometimes trans fat isn’t even trans fat. The same thing applies to the fat on your body. Depending on its location and composition, healthfulness isn’t distributed equally among adipose tissue. Some types of body fat are worse than others.

Fat is an endocrine organ. Like any other organ, it secretes hormones and other bioactive compounds that affect our physiology and determine our health.

Subcutaneous fat sits just below your skin. It’s the most conspicuous and least aesthetically-pleasing fat, comprising love handles and big droopy bellies, saggy arms and flabby necks, but it’s less actively harmful than many other types of body fat. Subcutaneous fat is the primary secretor of leptin, a strong regulator of appetite and metabolism, and of adiponectin, a marker for metabolic health with potentially anti-atherosclerotic effects.

Gluteofemoral fat is lower body fat, specifically the stuff that sits on your butt, hips, and thighs. In women, its presence indicates (and may even determine) good metabolic health. And it may not just be a signal for health, but an actor. Fat depots on the butt and hips actively secrete greater amounts of palmitoleic acid (PDF), a fatty acid with insulin-sensitizing effects. Gluteofemoral fat contains a greater proportion of omega-3 fatty acids, which are used to construct baby brains.

Visceral fat lies inside the abdominal cavity. It surrounds and envelops the organs. Contrasted with subcutaneous fat, visceral fat releases far less leptin and adiponectin. Instead, it secretes large amounts of IL-6, an inflammatory cytokine strongly correlated with systemic inflammation.

Intrahepatic fat is fat inside the liver. More than any other type of fat, intrahepatic fat is strongly associated with the metabolic complications of obesity.

Epicardial fat is visceral fat that surrounds the heart. If you’ve ever gotten a cow heart wrapped in hard yellowish fat, that’s epicardial fat. Large amounts of epicardial fat are associated with obesity, diabetes, and hypertension. And while epicardial fat appears to be primarily a signal of metabolic disturbances, it also exerts direct effects on heart function and releases inflammatory molecules that affect surrounding tissues.

Intermuscular fat lies between muscles. The less you use a muscle, the more it atrophies and the more fat will replace it. You may have seen the MRI of two thigh cross sections—one from a lifelong athlete and one from an age-matched couch potato. The athlete’s leg is a dense circle of bone surrounded by several inches of lean muscle in each direction followed by a small layer of fat. The sedentary leg is smaller circle of bone surrounded by a mishmash of marbled meat with several inches of thick white fat. Delicious and tender when seared, I’d imagine, but terrible for the person’s health and ability to function.

Intramuscular fat lies inside the muscles. Kobe beef steaks have lots of intramuscular fat. It’s the marbling, the presence of fat between muscle fibers. If you actually utilize it, intramuscular fat provides a nice source of energy for the muscles. Then again, if you were using your muscles in the first place it’d be tough to accumulate much intramuscular fat. The quickest way to get rid of intramuscular fat is with low-level aerobic activity. Staying under 75% of max heart rate will keep you burning predominately fat, and exercising while on a ketogenic diet is an even better way to do it; nutritional ketosis increases exercise-induced intramuscular fat oxidation 20-fold.

Brown fat isn’t really fat. It is, but it isn’t. Like muscle, it’s highly metabolically active. We use it to generate heat (thus burning energy) in response to cold exposure. Babies have a ton of brown fat, since they can’t shiver to stay warm, and until recently researchers assumed adults didn’t have much at all. Now we know that’s wrong. Cold plunges, swimming in cool water, and even going outside in short sleeves and shorts in cold weather can all stimulate the formation of brown fat in adults (I wouldn’t advise dunking your newborn in an ice bath for the health benefits). Those jerk babies aren’t the only ones enjoying that sweet, sweet brown fat after all.

Best of all, “training” for brown fat—in one study, exposing yourself to cool weather (60°F) for just 2 hours a day for six weeks while wearing light clothing—can increase energy expenditure and reduce overall body fatness. That’s not even a big dose of cold. Forgetting your jacket at home is probably enough.

Different populations have different body fat distribution patterns. Let’s look at a few:

South Asians (Indians, Pakistanis, Bangladeshis) have smaller subcutaneous “reservoirs” than whites, so a larger proportion of weight gain in this population diverts to visceral—and more dangerous—fat stores. Dr. Ron Sinha wrote about this (and still does on his blog) in the fantastic South Asian Health Solution.

Compared to Australian whites, Japanese men have more body fat for a given BMI.

Black Americans have less visceral fat and more subcutaneous fat for a given BMI than white Americans (PDF). Oddly, this doesn’t translate to a lower risk of diabetes.

Australian Aborigines have more trunk fat and less limb fat for a given BMI than Australians of European descent. Aborigine women have higher waist circumferences and waist:hip ratios than Aussie European women for a given BMI.

Men and women carry fat differently. I mentioned that briefly above in the section on gluteofemoral fat, and I covered the differences extensively in a previous post. Go read that now. In short, men are more likely to store fat on the trunk and around the waist, leading to the fat-guy-with-stick-legs syndrome. Women tend to store fat in the butt, thighs, and hips. Upon reaching menopause, women stop producing as much estrogen and begin storing more fat in the waist and abdomen.

The eternal question persists: is it cause or signal? Risk factor or actor? For most of these types of fat, the answer is probably “both.” Fatty liver indicates metabolic dysfunction, but it can also impair the liver’s functions and lead to insulin resistance and eventually diabetes. People with lots of brown fat may be lean and healthy because they spend a lot of time being active in cold weather, but the brown fat also increases caloric expenditure. Large amounts of intramuscular and epicardial fat indicate a sedentary lifestyle, which is damaging in its own right, but the fat secretes inflammatory compounds with real biological effects.

Teasing apart which link along the chain of causality is to blame is probably impossible. That doesn’t mean we can’t make a few safe recommendations.

Women shouldn’t stress out about a little butt, hip, and thigh fat. It’s likely a good sign.

Belly fat is bad. Fat around your heart is bad. Fat in your liver is bad. Subcutaneous fat looks bad and is hardest to burn but might not be too unhealthy. Losing weight will reduce all of it.

To target belly fat, intense training works best. The resultant spike in catecholamines will preferentially target visceral fat. Just be sure to get enough sleep, rest, and recovery, as chronic stress and under-recovery tends to chronically elevate the catecholamines and make belly fat more stubborn.

To target liver fat, limit sugar, eat lots of choline (from yolks and liver), and practice high intensity interval training. When you drink alcohol, make sure you protect your liver with saturated fat (beef, cocoa, coconut fat all protect against alcohol-induced fatty liver).

To target intramuscular fat, exercise in a low-carb or ketogenic state. Nothing too intense is required. A long, reasonably intense hike (lots of hills) on an empty stomach twice a week might do the trick.

To target epicardial fat, exercise. Both intense and moderate-intensity training seem to work.

To get more brown fat, forget your jacket. Heck, burn it. Just don’t stand too close to the fire.

If it sounds confusing, it shouldn’t. The basics apply. Recommendations haven’t changed. I just find all the different types of fat incredibly interesting. Don’t you?

Thanks for reading, everyone. Take care and be sure to let me know what you think about all this.

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TAGS:  body fat

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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43 thoughts on “Why the Kind of Body Fat You Carry Matters”

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  1. Love the ending…if this sounds confusing, it isn’t. The basics still apply. I find that true with so many things. And yes, Mark, I found this very interesting. Thinking of fat as an organ makes me look at it completely differently.

  2. Fascinating! I love the breakdown of the different kinds of fats, since obviously many of us here have learned that not all fat is created equal.

  3. I’d like to think that I’m not boasting a ton of epicardial fat, since the concept of fat giving my heart the squeeze is kind of a gnarly visual.

  4. I think I’m going to start forgetting my jacket on occasion. Let the brown fat do some work! 😉

    1. I always lean out in the winter (even leaner than I am already). Just the opposite of most people. In the winter the water is colder, denser and the waves and currents are stronger. You burn a ton of energy just keeping warm when the water is 50 degrees and the air is 38 degrees….never mind the power of the waves. However, I wonder if the brown fat activation doesn’t play a big role in my winter metabolism. In the winter we often come in because we cannot fight the cold any longer. When you’re shivering uncontrollably and grinding your teeth for a half an hour it’s a good signal to go in. My sessions are generally and hour and half to two hours. I’m probably a brown fat factory in January.

  5. It’s strange to think that when we lose body fat, that includes all the nooks and crannies you’ve described above. “My, Martha, what a slim epicardial, intramuscular, and intrahepatic figure you hold. How do you do it?”

    1. Oh Katherine, I store it all in my Gluteofemoral area and cover it with a glorious hoop skirt of course!

  6. “nutritional ketosis increases exercise-induced intramuscular fat oxidation 20-fold.”

    Woah. Better buy a pack of ketone strips so I can make those muscles shine!

  7. I’m really curious about the section on brown fat as it relates to babies — how much is healthy versus what’s too low or too high.

    While I’m sure genetics and environment are determining factor, I’m starting to witness an alarming number of people feeding babies carefully measured portions down to the molecule on a stringent schedule based shooting for the bare minimum level suggested by the pediatrician in the name of fighting obesity.

    These babies are very trim, and by all means otherwise healthy, but in a constant state of crying to be fed.

    My primal mind naturally thinks if their bodies produce this stuff so easy in a specific type, then nature must have a specific plan for it.

    Any ideas of what’s indeed healthy? Anyone else seeing this tend and alarmed by it?

    1. Oh dear, I agree with you that this sounds awful! I’ve noticed that babies exclusively breastfed on demand can carry lots of fat or seemingly hardly any. As you say, genetics and other factors (including stress levels) will count. Scheduled feeding plays havoc with the child’s own appetite control and confidence in their ability to communicate effectively. Crying to be fed sounds like a pretty big clue that the child is hungry – no amount of measuring and charts can tell you when your particular baby is preparing for a growth spurt. A risky strategy, I’d have thought.

      1. Yes, it breaks my heart when I hear little ones crying and their mothers ignoring them so they can continue to shop or whatever. They are either hungry, or cold, or hot, or uncomfortable from sitting or lying in the same position on a wrinkled blanket. Pick up your darned baby!!

  8. Love this one! I DO find all kinds of fat very interesting. Thanks.

  9. “Delicious and tender when seared, I’d imagine… Very funny Mark 😉

  10. Another five months or so and I’ll be back to growing more brown fat again. I like to think that’s the reason I never get really cold even working outside in the middle of a South Dakota blizzard. Just cover my skin enough to prevent frostbite and I’m good all day.

  11. Hmmmm, this is very interesting. I have a ways to go, about 60 lbs. So I’ll revisit this when I hit my goal weight and see where the fat settles and what I need to target. 🙂

  12. Do these various fats have different weights? If different types of exercise target different deposits of fat, what would be the best “value” for weight loss?

    1. A pound of fat weighs the same as a pound of lead. I think you mean best value for volume loss as perhaps different fats occupy volume per pound of weight.

      I would guess fat that sits on the outside of our muscles and body cavity would have less volume per ounce because it would be pretty easy for your body to just to slather it on loosey-goosey rather than carefully tuck in between muscle cells and organs.

      That’s just wild speculation though. I have nothing to back it up.

  13. LOVE IT! Always been a pear…large gluteofemoral region and tend to keep a flat abdomen haha but it’s good to know that it’s a decent thing…not a horrible thing! And yes, all the different types of fat really interest me as well 🙂 Thanks for the post!

  14. I Love all the different types of fat… bacon, eggs, butter, avocados, coconuts, lard…

  15. Hey Mark,

    Can you add some pointers on how to effectively target subcutaneous fat… Having trouble getting rid of the love handles and a little bit of belly overhang! Inspite of getting my body fat down to around 16% (from 28%).

    1. As someone who puts every once available body fat on my love handles and chest, I’m going to break the bad news to you. If that’s where your body likes to put it, you’re pretty much stuck with it. Meaning, it will take moving heaven and earth to melt those down to what you consider an acceptable level, and then constant vigilance to keep it away. I’m not saying it’s not a worthy goal, just be prepared that your version of “ripped” will be probably be much softer looking than the six pack crowd that never store any fat on their belly.

      1. Thanks for the reply Clay… Not what I wanted to hear but I know you are right as o just cannot seem to get rid of this bit of belly overhand and love handles!
        Am just going to have to be content with a keg (instead of a 6 pack) and continue to live primally!

        Btw love must of your comments!

        1. I’m in the same boat you are. I’ve had a belly overhang most of my life and I don’t think it’s going anywhere. But I will note that lip liposuction does nothing for skin – it’s like emptying a balloon that was overfilled. The balloon/skin is still about the same size, just with nothing filling it, So more than likely you would still have a hang, it would just be skin. Not meaning to be a pessimist, but a lot of people look at Lipo as a cure-all that it’s not.

        2. Try being 71 years old and beginning to lose lots of belly fat, love handles, and fat under the breasts! Yes, the skin hangs a bit, and it wrinkles and crinkles but you know, I’ll take that over a heart attack or stroke, or inflammation. I know that at my age this skin is never going to spring back!

          In my case I have been tortured by sciatica when sleeping for about a year, from a ‘bad back.’ Very little pain when I’m on my feet. But since I’ve been eating high fat, low carb, and intermittent fasting (20/4) my pain level has gone from a 9.5 to a 3.5 in three weeks. Oh, and I’ve lost 3 lbs from my already slim frame. The weight has been coming off from the top down (collar bones are showing more) but the mid-section is were I can SEE it most and it’s fantastic!!!!!! Watching youtube presentations by Dr. Jason Fung got me started intermittent fasting, but Mark’s Daily Apple is where I come to read about real life, and real people.

        3. Liposuction really ignores the endocrine function of the fat cells that are being removed. The cells are there no matter what, the difference between fat and thin is how much sugar is stored in those cells. So go ahead and remove those cells, but if you gain weight, it only goes to where the remaining fat cells are. To recap, get the lipo, get a tummy-tuck to remove the now-empty skin, and don’t gain any more weight.

  16. “I’ve got all the wrong fat in all the wrong places … been eatin’ my meals in all the wrong places … ”

    With apologies to Johnny Lee.

    Actually I’m pretty fit and trim mostly but need to do more HIIT to reduce that damn belly fat. Thanks for the reminder Mark.

  17. Do you have to actually feel cold to trigger brown fat? Wondering about running in 20F weather with appropriate clothing to feel comfortable – say a light long-sleeve shirt, running tights, glove liners and a wind vest – or should I be raising goosebumps and shivering to get the benefit?

    1. I think the experience of the cold is the trigger. If you are going to go out but bundle up, I think that would only be marginally better than staying inside the house which is really the same function as clothes, only less mobile.

  18. So what if you’re a woman who naturally does not have big hips, butt and thighs? Is that bad? I don’t have a lot of abdominal fat either, but I’m the opposite of this ideal pear shape, when I do gain it goes there and my breasts before ever hitting the “good” areas below the waist. My body has been this way my whole life, though I’m not overweight at all I definitely don’t have big hips.

    I’ve also been Primal for 6 years and had two healthy children rhay I’ve had great success breastfeeding, so I guess the fat is going somewhere beneficial. Always annoying to read something that is “good” that you don’t have and that you have no control over obtaining.

    1. Mark is referring to hip and butt fat for women being metabolically neutral and perhaps beneficial from an evolutionary perspective. Meaning, if you got some junk in the trunk don’t stress about it. It’s not hurting you. If you don’t have it, no problem as well. You’re not supposed to go and try to get some. Same with love handles for men. It’s pretty neutral. For men, It’s the pot belly that creates so many health problems.

      I don’t take any of this very seriously. It’s more of an intellectual curiosity, and a bit of cheer leading ra-ra validation for my choices.

      As much as I love MDA, if you don’t take it all with a grain of salt and keep some distance from all the articles and advice and studies, you are at risk of developing eating disorders and body issues. It’s not healthy to react to every new study or think about it too much.

      Mark has to because it’s his job. And I’m sure he’s developed a set of metal tools to deal with such an intense focus on diet and exercise without feeling like he’s a slacker and loser for not doing enough.

      Just work the basics and let the chips will fall where they will fall.

  19. Would love more info on fat as an endocrine organ. Oddly I get heart palpitations particularly during hormonal periods. I swear they seem to emulate from my viseral abdomen fat. They have improved as I have lost weight. But I think fat is not a static lump but a concerted actor on the body hormone functions. The human body is so complex and awesome!

  20. I am a 25 year old woman. I weigh 115 lbs, and I have always carried my fat around my stomach area instead of my hips. I have a thick waist for my size. Should I be worried about my thick waist, although my BMI, cholesterol, triglycerides, blood sugar, etc. are where they should be? Also, is there anything I can do about the fat around my waist? I don’t particularly like how it looks!

  21. Wow! Interesting resource. I never heard before about these huge number of different fats. I have belly fat and now trying to reduce it.

  22. Mark,

    Its 2016. There are no differences between men and women, or different races. Gender and race are both social constructs.

    I wish we woulds stop talking about people like this. Ugh.

  23. For anyone who has loose or saggy skin, wrinkles, you may see benefit from supplementing with copper, vitamin C, collagen, selenium. Dr. Peter Glidden says there is a point of no return, but we don’t know what/where it is.

    Other symptoms of copper deficiency are white/silver/gray hair, varicose/spider veins (hemorrhoids), and possibly at the extreme end – aneurysms in the brain, heart, abdomen, kidney.

  24. So, how do we get to reducing the visceral fat? I’m reducing everywhere with paleo and strength training etc but the tummy is melting at snail pace.

    Any tips?

    And yes, Thanks for the very informative article!

  25. Hi Mark
    I’ve been following a Keto diet (for the most part – Christmas!) for about 2 months.
    Really enjoying the food and have lost 6 kgs ?
    I’m a 66 year old female who used to be very active -Ironman in 1990
    A leg injury turned me into an outrigger
    A shoulder injury requiring surgery was what stacked the weight on a year ago
    Am back to yoga and water aerobics.
    Scary thing about a month ago whilst into the diet I had a heart scare.
    Am seeing a cardiologist in a few weeks but today had an InBody Scan at a local supplement store and it said my ‘visceral fat’ was 19…..
    He was an anti Keto guy and said I should not continue with that diet because of the risk to heart.
    Really I’d prefer to stay on the diet and get another test in a couple of weeks to see if anything’s changed.
    Would you please comment on Keto and its effect on visceral fat?
    Thank you! Sue