Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
21 Aug

Gender Differences in Fat Metabolism

A few months ago, I addressed the role gender plays in how we respond to intermittent fasting. That post sparked a great discussion, and I’ve since received a fair number of emails from readers eager to learn other ways in which gender plays a role in our health and nutrition. One email in particular set me off on a round of research. So, a hat tip to you, Winifred, for giving me something to think, learn, and write about. I hope everyone finds it to be helpful.

As you may know, women and men store and metabolize fat differently from each other, and a 2008 paper (PDF) reviewed the evolutionary reasons for these differences. Here’s a summary of their findings and few other noteworthy factoids:

Women carry more fat than men. They are better at storing fat than men. Moreover, when women store fat, they do so in different places than men. They’ll preferentially store fat in in the hips, butt, and legs, whereas when men gain weight, it usually goes to the upper body (hence why you see massive beer bellies atop stick legs). Furthermore, when both men and women store upper body fat, men are more likely to develop visceral fat – the abdominal fat associated with metabolic syndrome – while women are more likely to develop subcutaneous fat.

On women, body fat seems to be healthier and less problematic. The characteristically female lower body “gluteofemoral fat” is actually a strong sign of metabolic health, whereas abdominal fat is not. In men, high body fat levels correlate strongly with insulin resistance, while this relationship is much weaker in women (probably because of their lower tendency to store visceral fat).

Women burn fat differently than men. Upper body fat goes first, while lower body fat tends to stay put. Except during pregnancy and lactation, when the lower body begins to give up lower fat stores far more readily. Interestingly (and not by coincidence), women tend to preferentially store the long chain omega-3 fatty acid DHA – the one that’s so important to the baby’s development during and pregnancy – in their thighs.

Women make more triglycerides than men do, but their serum levels are similar. This indicates that the fat is being taken back up into adipose tissue at a higher rate in women than in men.

Women are better at burning fat in response to exercise. During endurance exercise, they exhibit lower respiratory exchange ratios than men, which indicates more fat burning and less carb burning.

Women are better at converting ALA into DHA, and they also tend to have more DHA and AA circulating throughout their serum than men, who have more saturated and monounsaturated fat.

These differences in fat metabolism aren’t seen in isolated muscle cells of men and women, which isn’t really surprising. We’re made with the same basic building blocks; we just run on different software. The differences are systemic and hormonal.

Why does this sexual dimorphism in fat metabolism exist?

Well, the name of the game in evolution is reproduction, and reproduction is far more nutritionally expensive for women than it is for men. I don’t think I have to spell out why – for a man, the reproductive process is a brief moment in time, a half tablespoon’s worth of effort; for a woman, the reproductive process lasts the better part of a year and represents a significant drain on nutrient stores. As such, women are “designed” to hold onto said nutrients because, as far as evolutionary fitness is concerned, her primary purpose is to feed, nurture, and cultivate an entire other human being inside her body for nine months. Think about that for a second: women have to create and support another life inside their bodies. They have to provide the food, the water, and the shelter. If something goes terribly wrong in the “outside world,” that nutrient flow to the fetus could be interrupted, thus putting her evolutionary purpose at risk.

Now, imagine if the body didn’t know best. Imagine if the expectant mother had to know precisely what the fetus needed at any given moment – what precise nutrients were needed, which foods to eat and when to eat them in order to provide said nutrients, what to drink and how much of it, what not to eat nor drink – and then make a conscious decision to provide those things right on schedule? It wouldn’t work. We wouldn’t be here. Luckily, the body “knows.” The body will draw on what’s stored and what’s provided to make a health baby. And if it’s not all there, it’ll even convert other stuff into the stuff that it actually needs. Sure, a good diet will absolutely improve fetal health, but we’ve all known parents with less-than-ideal diets who have healthy kids. The body knows.

Which is why women store and burn fat differently than men. In order to be able to provide those nutrients to the growing child, female bodies store certain types of fat in certain places on the body. Female bodies “hoard” certain types of fat and are loathe to relinquish them “just cause you had a simple caloric deficit.” Whereas a man could go low carb Primal and lose weight pretty easily because all he “has” to be able to do is provide a bit of sperm, a woman’s body has more important things in mind, like having enough body fat on hand to produce enough leptin for optimal fertility, or enough DHA stored in lower body fat to build a robust baby brain.

How does this affect my recommendations or your diet, if at all?

Women – don’t be concerned about a little (or more than a little) subcutaneous body fat, especially on your lower body. If you’ve been trying in vain to lose that stubborn jiggle on your thigh, consider that maybe, just maybe it’s there for a reason. Even if you’re not interested in having a child, it’s likely that the presence of lower body fat indicates good health. You don’t have to get pregnant, but the ability to do so is probably a marker of good health, and the research outlined above suggests that classically feminine patterns of fat deposition are healthier than classically male patterns. And even if you don’t like your glutofemoral fat, rest assured that the males in your life (even ones as far away as Papua New Guinea – PDF) likely do!

Men – most of the fitness and health literature is geared toward you, so I’ll just suggest that you take this information on gender differences in fat metabolism into consideration.

I’ve always stressed the relativity of a person’s ideal body composition. I’ve discussed my own failings at trying to eat big and lift big to get big. I managed to put on five pounds of muscle by eating and working out way more than was comfortable or natural, but it made me lethargic, and as soon as I skipped a meal or workout, muscle would just peel off. That’s my comfortable body composition. Your ideal body composition might look very different, and, if you’re a woman, it might look very different from a man’s. That’s fine. That’s natural. That’s attractive. That’s how it’s supposed to be, and by trying to fight it – in either direction – your health may suffer.

What do you folks think about all this? Does this take a load off your mind, or does it open up new avenues of inquiry? Let me know in the comment section!

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. I’m with many of the women on here. I lost 3 stone eating primal but my belly is huge. i have lost 9 ” off my middle but its still huge. I’m apple shaped and as heart disease and diabetes is in my family I’m obviously concerned. I have Fibromyalgia and cant exercise, my sleep is erratic because of the Fibro so dont tell me to get a good nights sleep and relax! it doesnt happen! I would love to have a flat , fairly fat free stomach. I’d also like to know mark, if I stick to my primal way of eating but still carry the belly fat what are my risks of developing diabetes and heart diease in the future?

    cinders wrote on August 23rd, 2012
  2. I’ve always had the proverbial “childbearing hips” and “thunder thighs” no matter how slim I was and had actually resigned myself to the idea that I’d probably have to resort to plastic surgery to get the visual results I wanted. A few months ago I read Nina Planck’s Real Food for Mother and Baby since I’ve been searching for paleo/primal-friendly resources for conception and pregnancy. Her book also discusses that DHA is preferentially stored in the gluteofemoral fat and was a HUGE AH HA! moment in coming to terms with my body. That bit of jiggle is going to be major brain-food (literally!) for whatever podlings I eventually have. It gave me a whole new appreciation for human physiology and all the things that we’re capable of. Not to mention giving me even more reasons to love my curves.

    Laney wrote on August 23rd, 2012
  3. My question is it okay to not have a period for awhile while being on the primal diet/lifestyle? I train hard 4-6 days per week and am very low carb. I am about 10-15lbs from my vanity weight, at about 21% body fat and would like to get leaner. I’m not having a period , should I be concerned or will it come back once my body adjust to this lifestyle?

    Grace wrote on August 24th, 2012
  4. For those of us who have “Wonder Thighs” what brand of jeans do you wear? It’s very difficult for me to find jeans that will accommodate my Wonder Thighs and still fit around the hips and waist. I’ve had luck with American Eagle Boyfriend pants cause they’re larger in the thigh and have a low rise.

    What else do you wear?

    christina wrote on August 24th, 2012
    • Start with a relaxed or curvy fit, then find yourself a great alterations person and plan to have the waist taken in. That’s what I finally had to resign myself to as the ‘perfect’ jean is a MYTH. So look for something that really flatters your butt and thighs and just have the waist altered.

      K.C. wrote on August 25th, 2012
  5. Thanks Mark for that article. I am fairly new to PB, my first miracle being the stabilization of my blood sugar (no more crashes for me!), but I have struggled with fluxuating weight, bouts of fatigue, loss of libido, lost desire to workout, etc, your leptin article really helped with that issue, I figured out I’m one of those that need a certain amount of carbs or my leptin levels go all wonky. This article about the differences in men and women’s fat metabolism makes me feel much better, my husband who has been mentoring me in primal seems to lose the fat so easily when he eats clean true primal where I will bounce back and forth seeming to lose and regain the same pound every other day. I have also lamented the fact that the fat loss seems so slow. I will now have more patience with myself and concentrate on reducing my stress and getting enough sleep. :)

    K.C. wrote on August 24th, 2012
  6. Women burn fat differently than men. Upper body fat goes first, while lower body fat tends to stay put. Except during pregnancy and lactation, when the lower body begins to give up lower fat stores far more readily. Interestingly (and not by coincidence), women tend to preferentially store the long chain omega-3 fatty acid DHA – the one that’s so important to the baby’s development during and pregnancy – in their thighs.

    THIS makes me feel SO much better! I’ve always had an easier time losing weight in my stomach area. After my face and chest, its the first to go…and usually within a month of exercising on a regular basis.

    So when its been my thighs and hips lately that have been getting slimmer while my tummy stays relatively the same, I’ve been wondering what’s gone wrong? Is it that I have no abdominal strength? Or did my body chemistry change?

    OH! That was it! I’m currently nursing a 7 month old and have been exercising for the better part of 3 months now (5 days/week ~30 min of cardio/day + 45 min of weights 1-2x/wk). This makes me feel so much better. I’ll just keep up what I’m doing and look for the results in February – March!

    Christina wrote on August 24th, 2012
  7. Hello,

    This post has revealed a stunning piece of information which most of us never knew. Of course, we are not trained in medicine to get to study these facts. So, the bodies of men and women are designed differently to store fat. This article should surprise both men and women.

    Thanks a lot for posting such a valuable post with so much of information useful for all of us.

    Regards,
    Andy

    Andy wrote on August 25th, 2012
  8. Pancreas releases insulin. Insulin tells cells to take up fat.

    Eat a lot of glucose molecules and a lot of Insulin works hard to store it safely. High blood glucose damages cells.

    Excess alcohol and fructose are turned to fat by liver.

    Good fats and proteins reduce insulin needs to a minimum.

    Insuring replacement of all 60 essential minerals allows the other hormones to put the fat where it belongs or burn it up.

    Paul_S wrote on August 25th, 2012
  9. I’m not sure about this whole “fat thighs are healthy” thing. I thought it was a sign of estrogen dominance. Then there’s cellulite – surely not a sign of vibrant health. Are there paintings of hunter-gatherer women with big thunder thighs?

    Elisa wrote on August 25th, 2012
  10. The .pdf download of the research paper is not working, could you fix it?

    cfh wrote on August 26th, 2012
  11. 2 tips for the women posting here.

    1. For your thighs: foam rollers. Google it. Cellulite is formed by connective tissue; rollering it helps smooth it out. Worked for me — didn’t get rid of cellulite altogether but turned the clock back 10-15 years.

    2. For your belly: add an exercise to your routine that contracts the transverse abdominis — an ab muscle that gets weakened and stretched during pregnancy. Getting the trans abdominis toned will help pull that pad of abdominal fat up and in. Not a cure for the fat itself but makes it more presentable 😉

    Kirsten wrote on August 26th, 2012
    • Thanks Kirsten. I’ll try the foam rollers.

      Elisa wrote on September 2nd, 2012
  12. I too enjoyed the article except he kid of left out that there are different body shapes period. Apple versus pear for one. Apple shapes DO NOT GAIN weight in their legs, harder to build muscle even besides basic. I mean mine are shapely but not athletic like my tube or pear shaped friends.

    I struggle with losing weight in my specific apple shape problem areas. It is like i have a rubber band just below my thighs and up. Apple shapes abdomen is at about four inches shorter than everyone else’s and yet we still have to fit the same amount of organs and such missing that space.

    We gain most of our fat in the upper region and it is the last to come off if you can get it off :). Before children when i was slender i still looked bigger because of this. I would like to lose about 25 more pounds and even eating a low carb Nourishing Traditions diet for yrs and it is not really working. I tried carb increase for a while do not think it is working. It is like my body is just stuck here. We have been gluten free for a while. I usually only have fermented dairy and have been with out as well and did not notice any difference. I have to kill myself with exercise to budge weight and even then it leaves the other areas not my apple section!

    MDA do you have an suggestions??

    GrokMom wrote on August 29th, 2012
  13. What about the female who is past production age, who is just now, at 77 yrs, acquiring a wider girth? The primary change has been less exercise during the past 3 yrs due to surgeries, cataract (2010); hernia repair (2011) and the extreme heat/mosquito virus that prevents prolonged outdoor activities here in 2012. I never had a real weight problem and want to lose 10-15 lbs now to combat high blood pressure. I have gone up from 116 lbs. to 126.5-129 lbs. I am flummoxed!

    Goldie H. Summage wrote on September 9th, 2012
  14. Ok, this has always frustrated me, because I gain weight like a dude! *insert angry face*. I am 5″3, 116 lbs, and while the rest of me is fit and healthy, ALL of my fat is in ONE, SINGULAR spot. My stomach. I literally look pregnant. I cut out wheat in july and instantly noticed a difference. But I am wondering if replacing the wheat with more ice cream and chips is catching up to me. I cut out sugar this week, and other than that I eat eggs, bacon, fruits, veggies, meat, fish etc. But this belly. It’s so annoying.

    becca! wrote on September 26th, 2012
  15. Great article.
    Everyones body is different and not everyone thrives on the same foods. When you move your body , eat healthy and dont restrict, and you still carry some extra weight on for example your ass, then dont judge it. Then it may be just natural for you:)

    Ann wrote on January 17th, 2013
  16. change gender to sex…
    gender is socialized brah

    steffo wrote on February 21st, 2013
  17. Hm… male and female fat distribution and why it is the way it is really is interesting.

    For transgender women on hormone treatment out fat distribution becomes like any other female but it works best for trans kids that start before or as puberty kicks in. Hormone treatment later in life is not as effective.

    Could or would having or promoting certain types of body fat, perhaps in a diet regime along with hormone treatment bring better bodily feminization (curves, shape) in trans bodies that started late in life with hormone treatment?

    Hormones only do so much. Are there certain treatments or medication that can promote certain useful types of body fat that could help combined with hormone treatment?

    This is interesting.

    Louise wrote on February 23rd, 2013

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