I would assume most men really care about
testosterone and fertility. This short on testosterone has become pretty popular. It's a
clip from this interview with Andrew Huberman on the "Mark Bell's Power Project Podcast."
[Andrew] "If you're not getting enough fat, forget having decent testosterone. If you went
on a low-fat diet, sub caloric low-fat diet, is, you know, it's a form of nutritional
castration, basically. Some people require more fat than others, but that is absolutely deadly to
the reproductive system. If you increase your fat, in particular saturated fats…the vegan community
is pretty angry with me right now because I said, sin of all sins, I said that I eat butter.
I like
grass-fed butter not I don't eat chunks of it, I eat a little bit of it. And there's a video on
the internet saying, you know, he's bad advice. My blood lipids are great, thank you. Dietary
cholesterol is, is vital for hormone production. Some amount of saturated fat is good. If you put
your saturated fat to zero, your testosterone will drop. There's no question about it." I assume he's
exaggerating there, but just in case he's not, who eats a zero saturated fat diet? Even a 2,000
calorie diet of just bananas has some amount of saturated fat, like, 2.5 grams.
Everybody eats
some amount of saturated fat, even people on a low-fat diet, even vegans. Vegans can eat a lot
of saturated fat, if they want to. But really, he has two claims here. So first, he's saying
that low-fat diets are bad for testosterone, they are nutritional castration. [Andrew]
"If you went on a low-fat diet, it's a form of nutritional castration, basically." That's
a fantastic phrase. And then the second claim, saturated fat is good for reproductive health
good, for testosterone levels. [Andrew] "Some amount of saturated fat is good. If you put your
saturated fat to zero, your testosterone will drop. Let's start with saturated fat. Is there
any evidence on saturated fat and testosterone? There is, and at first glance, it seems to support
Andrew's claim. This study found that both total and bound testosterone levels were higher for
those eating a high fat diet, with almost four times more saturated fat than the low-fat group.
This one, very similar, with the high fat group eating more than double the amount of saturated
fat.
One of my favorite sources for nutrition and supplement information is examine.com. They're
about as unbiased as you can get. No ads, no sponsorships. They don't sell supplements.
Highly recommend them. Anyway, as they point out about these studies, the differences found
are small, 10-15%. And more importantly, the low-fat groups, their testosterone levels
are still within the normal range. And the biologically-active, the free testosterone, the
testosterone that your body can actually use, was the same between groups. Probably why examine
makes no mention of saturated fat on their page about boosting testosterone. So it really does not
make sense to eat saturated fat for testosterone, but if for some reason you think you need it,
you don't have to harm animals to get it. The only things he mentioned, of course, is, like,
butter and beef and egg. [Andrew] "For me, butter, red meat from good sources, is wonderful. Eggs are
really good." Coconuts exist and they are full of saturated fat. So now on to Andrew's second claim,
that low fat is bad for reproductive health, for testosterone. [Andrew] "…absolutely deadly
to the reproductive system." It's important to note that the studies about saturated fat that
I mentioned earlier, they weren't really on saturated fat and testosterone.
They were on total
fat intake and testosterone. So not only were the low-fat groups eating low saturated fat, they
were eating low fat in general, very low fat, less than 15 percent in this study. On a 2,000
calorie diet, that's only 33 grams of fat. And luckily for us, there is a recent meta-analysis on
this exact topic. They analyzed 6 studies total, 206 participants total, with low-fat intakes
from 6.8% to 25%. 6.8? What is that, like, 2 grams of fat? 15 grams on a 2,000 calorie diet.
To give you some idea of what that looks like, one avocado has 21 grams. So yeah, kill me. They
did find a positive correlation between fat and testosterone, the low-fat groups had lower
levels.
But there were several limitations: lack of randomized controlled trials, only 6
studies, small sample size again 206 participants total. As per usual, more research is needed.
You really cannot draw firm conclusions from this review. So to be so confident that a low-fat
diet is absolutely deadly to testosterone levels? Why? What about vegans, specifically? You
might have heard of this recent study that found normal testosterone levels for plant-based
eaters, whether they ate a healthy plant-based diet or an unhealthy one. Another recent one had
similar results no difference between vegans and omnivores. There could be a couple reasons for
this.
First, again, fat intake. If we look at that second study, we can see that while the vegan
men were eating significantly less saturated fat, as we would expect, overall fat intake was almost
30 percent of total calories, or about 64 grams of fat per day. So they were not eating a low-fat
diet, they were not following recommendations from organizations like PCRM that promote 20
to 30 grams of fat per day.
[Neal Barnard] "In the course of a day, about 20 or 30 grams of
fat, if you're reading labels or whatever, that's all you're going to need. You don't need
more than that." They were eating more than double the high end. Second, BMI. Multiple studies have
found a negative correlation between obesity and testosterone, and when people lose weight,
their testosterone levels rise quickly.Even a small reduction, a 5% reduction in weight, can
significantly increase testosterone levels. As we know, and as the second study shows quite clearly,
vegans tend to have healthy BMIs. Whatever the reason, the evidence clearly does not support
this claim that saturated fat is needed for healthy testosterone levels, and that vegans are
therefore at risk for low testosterone. Even the link between total fat intake and testosterone
is pretty weak. That's not to say fat is not important. You guys know me, I eat a whole lot of
fat. And if I were a man, I definitely would not take PCRM's advice and eat 20 to 30 grams of fat
per day." [Neal] "About 20 or 30 grams of fat, you don't need more than that." That was Dr.
Neil Barnard, he's president of PCRM.
He even says that we really only need 3% of total
calories coming from fat. That would be 6.6 grams on a 2,000 calorie diet." [Neal] "Maybe
only maybe about 3% of your calories every day should come from those fats. That's it." Which, it
might be true. I have no doubt that many people, if not most people, could survive on a very low
fat diet for a long time. But I don't think most of us are interested in just surviving, right,
on the bare minimum.
Higher fat is correlated with benefits that maybe don't impact longevity,
but that we really care about. I would assume most men really care about testosterone and fertility.
So going by the minimal evidence we have on fat intake and testosterone, and the good amount of
evidence we have on fat intake and heart disease, it just does not make sense for men to eat
a low-fat diet, vegan or otherwise.
Eating a decent amount of unsaturated fat, it may help men
achieve and maintain healthy testosterone levels. And if it doesn't? These foods are still healthy
and delicious. It's a win-win. Just for fun, let's look at fertility, in general. For both men
and women, saturated fat is linked over and over and over again to worse fertility. Now, does that
mean saturated fat is bad for fertility? No, it's a correlation. Nutrition research is rife with
confounders that are really hard to control for. The average person eating lots of saturated fat is
also eating lots of refined carbs, minimal fruits and vegetables, is sedentary, is overweight.
All of these are linked to decreased fertility. Perhaps someone eating lots of saturated fat, but
also eating lots of fruits and vegetables, is fit, is active,.
Maybe they wouldn't have an increased
risk for fertility problems? It's possible. But the evidence definitely doesn't say saturated fat
is good for fertility. What about veganism and fertility? There really isn't a lot of research
on veganism, specifically. There are a couple of sperm quality and motility studies. One found
vegans had worse motility. The other found vegans had better motility and better quality overall,
so not super helpful.
And also, the total number of vegans, both studies, only 15. So yeah, I don't
think there's a lot we can learn from this, other than vegans can have healthy sperm or unhealthy
sperm. Shocking! But things that vegans tend to do, again, maintain a healthy weight, eat fruits
and vegetables, limit mercury, right, we don't eat fish, seem too positively influence fertility
in various ways. And the evidence definitely doesn't say veganism is bad for fertility. Back
to testosterone. What if you're vegan and you have low testosterone levels, or you're just
worried about your testosterone levels? Well, besides saturated fat, Andrew also recommends
a couple herbal supplements. [Andrew] "Now, for people that aren't getting prescribed
trt, but want the increase in testosterone, they're these plant compounds like Tonga Ali
and another one, which is very interesting, it's a Nigerian shrub called fadogia agrestis."
Unsurprisingly, there's very little evidence for these, either.
But there are a few things you
can do. They're things that you really should be doing anyway. They're important for everyone,
beyond testosterone. Adequate sleep and physical activity, particularly resistance training.
Maintaining a healthy weight,. Adequate nutrition, particularly zinc vitamin D and magnesium. It's
hard not to get enough magnesium on a vegan diet, but you can definitely be lacking in vitamin D and
zinc. So make sure you have a source for those, make sure you are eating legumes and other
foods, pumpkin seeds, that are high in zinc. And make sure you're taking a vitamin D supplement
or getting some amount of sun. And of course, talk to your doctor. Who is Andrew Huberman? I wanted
to put this at the end instead of starting the whole video with "this guy's a quack." I wanted
to just look at his claims on their own and see if they hold up, right. But it is interesting. He's a
neuroscientist. He has actually done his research, I mean, literally he's done his research.
Which
makes this whole interview, and other interviews he's done, even more confusing to me. I mean, he
knows better than to rely so much on anecdotes and his kind of clinical experience with athletes.
And he should know that guidelines are not based on anecdotes or even clinical observation. That's
what research is for, to see if there is really a connection between testosterone and saturated
fat, for instance. Also confusing, he really emphasizes his own experience. [Andrew] "My blood
lipids are great, thank you. And I'll be happy to share my blood lipid profiles, and show I've done
the experiment." Who gives a [ __ ], man? I mean, again, this is what research is for. One person's
experience tells us one thing: it tells us about one person's experience.
But since Dr. Huberman
loves anecdotes so much, my partner, my husband, has been vegan for more than 15 years. We have
3 beautiful children together. Gosh, sometimes, like, I want to plaster them all over my channel!
A six-year-old, three-year-old, and a six month old. And we had no trouble conceiving. The first
two took one month, and then six month old, it was four months until I got pregnant. And there are
lots of other vegan parents out there. So clearly, not being vegan is "nutritional castration" and
"absolutely deadly" for the reproductive system, right? Has this guy been interviewed by Joe Rogan?
Like, you know he has. Oh yep, he has. I shouldn't have called him a quack. He seems like a nice guy,
and I like that he said he's not promoting lots of saturated fat.
[Andrew] "I never said to consume
butter in large amounts." But it seems like he, again, is really interested in anecdotes, which is
just weird, and seems to base recommendations off of that. He really seemingly wants to come off as
an authority figure, which I get, he apparently is actually working with patients on improving their
testosterone. But again, you don't make confident claims based on that, recommending supplements
that have virtually no evidence for what he's claiming, that they improve testosterone. It
seems like he is very easily influenced by minimal data. So not a quack, but, you know,
just just be careful, right. Just be careful listening to people. Always go for an outside
source. Always check consensus, right, Harvard health is really good. Again, examine.com.
Thank
you so much for watching everybody! I hope you enjoyed that. I would love to know your thoughts
on testosterone and veganism, or fertility in general. I was really interested in, partly
why this took me longer than it should have, I was reading a lot into the study that looked at
a healthy plant-based diet and an unhealthy one. They were using this plant-based diet index
from a different study that some researchers developed. And yeah, it's just very interesting.
So I spent way too much time looking at that, and it really was not relevant to this, but that's
that's what happens every time. Learning is too fun, I can't help it. Like the video if you
liked it. Subscribe. You can hit the bell if you want to be notified every time I upload a
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I've already uploaded the
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