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. So what does the research (or dearth of it) say about us women who have small hips and “beer bellies”? We’re as feminine as other women, produce offspring, etc. “Estrogen dominance” is common among the women in my family, and all of the women are built this way, with big breasts, big stomachs (if we don’t exercise), and “chicken legs.” I can’t think of one female relative with an hour-glass figure or who might be referred to as “hippy.” I grew up in Iowa, and most of the women there are built that way, so perhaps it’s a German/Irish thing?

    Karla wrote on August 22nd, 2013
  2. interesting article, but as a woman I still have no idea whether my different fat metabolism calls for modified diet, specially in regards to fat consumption? As women should we eat less of it? Should our proportion of consumed carbs be higher and fat lower in comparison with male diet?
    I’m new to primal lifestyle and from very beginning I felt ovewhelmend by amount of fat I was advised to eat… I just find it slightly scary and in my case impossible to achieve. But as advised I have switched to full fat products (I eat diary) and I’m still questioning whether it’s a good move… And yes, I’m not a big fan of big healthy lower body on my body 😉 I like athletic look, not skinny supermodel (yuk!), but lean and healthy with low fat %. So I’m still scratching my head wondering what is the best diet to achieve that optimal look…

    Kasia wrote on August 23rd, 2013
  3. interesting article, but as a woman I still have no idea whether my different fat metabolism calls for modified diet, specially in regards to fat consumption? As women should we eat less of it? Should our proportion of consumed carbs be higher and fat lower in comparison with male diet?
    I’m new to primal lifestyle and from very beginning I felt overwhelm by amount of fat I was advised to eat… I just find it slightly scary and in my case impossible to achieve. But as advised I have switched to full fat products (I eat diary) and I’m still questioning whether it’s a good move… And yes, I’m not a big fan of big healthy lower body on my body 😉 I like athletic look, not skinny supermodel (yuk!), but lean and healthy with low fat %. So I’m still scratching my head wondering what is the best diet to achieve that optimal look…

    Kasia wrote on August 23rd, 2013
  4. Hi Mark. I don’t have time to read the comments right now, so this may have been mentioned. I’d love for you to write something to women who have the apple-shaped body. We aren’t the ones with the nice rears and heavy thighs that are healthy. How should we eat? How should we exercise? Our body type is working against us! Also can we build muscle mass to become less insulin resistant? Thanks!

    Lynn123 wrote on August 23rd, 2013
  5. For the peri-menopausal gals contending with visceral fat, I’m wondering if it’s simply the body’s reaction to the natural reduction in estrogen that occurs at that time, trying to bring it back up to its previous set-point (since visceral fat produces estrogen). It’s known that estradiol deficiency causes abdominal weight gain.

    If this paradigm is correct, then supplementing with bioidentical estrogen (cream) might help reduce the visceral fat, since the body would no longer need it in order to bring the estrogen level back into line.

    Are there any peri-menopausal or post-meno-pausal women here who have used bioidentical estrogen cream? Was there any effect on visceral fat?

    Ann wrote on October 19th, 2013
  6. and the fatty cells are different in both gender

    omar essam wrote on October 19th, 2013
  7. Great Article and is the closest explanation to my pregnancies. I was overweight before pregnancy and have lost 18lbs and 25 lbs respectively within two weeks after delivery with respect to the pre-pregnancy weight. My second one i was diagnosed with gestational so my diet was stricter (i also had a one carb per meal rule and seemed to keep my on track) but I do know i lost appetites while pregnant, ate less than normal just due to being less hungry and never had any cravings. I’m sure which explains the loss in weight. Now that I am only 3 months postpartum and 25 lbs lighter I would like to keep my current weight and possibly lose more. I have noticed since the day I delivered I am very hungry and can’t seem to keep my hunger satisfied. Right after delivery i also noticed how thin my limbs and hips were very thin which no I know why through your articles explanation the fat stored there before was used by the baby. I haven’t gained any weight back but i am noticing my limbs are not as thin looking as they were when i got home from the hospital. Is there anything I can do to keep this thinness? Or should i just chalk this up to my body is preparing for another life? It did feel amazing being thinner than it does now because i feel more bloated and less agile. Or could it be that I can be the thinner look if I go to a primal diet because maybe my bloated look is intolerance to gluten, grains and sugar? I still consider myself slightly overweight and can still lose some more fat to be at a optimal health range. I don’t know…. frustrated and confused. Trying to find the answers and ways to acquire the thin and agile feeling!

    Jennifer wrote on April 24th, 2014
  8. hi Mark,
    I’m a woman in her mid-twenties. i’m 5’7 and weigh 120 lbs. i have about (19-)20% bf. but i still have a protruding fat belly and very bad love handles. once i lost to around 115 lbs, it got somewhat better. my abdominal circumference is 70 cm, when i lost the 5 lbs it was about 67. i am very desperate. i don’t know how much more to lose to look normal in tighter dresses and clothes.
    i would say i’m skinny fat, however, i do high intensity workouts regularly, little bit of weight lifting, i surely have built some muscle tissue, and have a body fat percentage around 19-20%. how is that skinny fat?
    have you ever encountered someone with this issue? thank you if you have any suggestions for me. i guess i just need to lose 10-15 pounds and then i will be ok. but wont my bf% be too low? thanks!

    Lea wrote on April 18th, 2015
  9. It’s difficult to lose weight and I think it’s determined by gene!

    David Andrews wrote on January 30th, 2016
  10. I am at a low -ish body fat, for woman, 22-24 but how come the fat that I do have is not in the “sexy” places, but rather it is how men store their fat, like lower back and midsection???

    Andrea wrote on June 5th, 2016

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