there's a new Netflix documentary on diets and it's been the usual very mixed reception, with
some people celebrating it enthusiastically and others shooting it down, with a lot of vitriol in
some cases. it's a four episode show, it's called "you are what you eat" and it's been one of the
most watched shows on Netflix since it premiered. the show follows the Stanford twin experiment,
which is a study we covered here recently where they took 22 pairs of identical twins and they
assigned them randomly to either a vegan or an omnivore diets. in the show we meet four of those
pairs of twins that participated in the study and we follow their experience. we see the session
where the twins got assigned to their respective diets and there is significant trepidation about
being assigned to the vegan diet. one pair of twins are professional chefs that cook with a
lot of animal products. another pair are cheese experts and aficionados. so these are people whose
normal day-to-day lives are very much non-vegan. now, this type of show is usually heavy on the
anecdotes and the personal stories. that's almost inevitable, the vast majority of viewers are going
to connect much easier with anecdotes, with individuals, than with abstract data or bar
graphs. this one, as TV shows go, actually goes back and forth between showing aspects of the
study and other, more personal, anecdotal-type episodes. in general, the show is pretty open
about where its allegiances lie. they bring on several vegan advocates, we hear testimonials
from people who put diseases in remission using vegan diets, they interview a Michelin star Chef
who turned his entire award-winning restaurant in a completely plant-based Direction. They
even feature the CEO of impossible foods and the founder of a brand of vegan cheese. I think it's
fair to say it's not really a show about nutrition science per se, it's a show about vegan diets,
about veganism, about plant-based diets, perhaps. and the showmakers are pretty obviously excited,
enthusiastic about vegan diets and are sort of extolling them through this show. now,
we hear a couple of common scientific claims. in the section about cheese we hear this idea
that casomorphins are addictive and that this is why people struggle to give up cheese. I've heard
this claim made a number of times, from different vegan Advocates, but I've never actually seen any
scientific evidence for it, so I tried to look, and I couldn't find much in terms of compelling
evidence in humans. there are studies of casomorphins in lab animals like rats for example,
but I haven't seen anything showing an addictive property. one study even concluded "milk products
containing casomorphins are not likely to become the focus of addiction". so if the evidence is out
there in human beings, I'm open to it, I haven't seen it yet so at this point I don't know if
there's anything else to this than storytelling. another claim we hear on the show that is also
common out there is that substantial Dairy intake can increase risk of prostate cancer. this is
another one that's very common to hear. there is truth to it, there is a link between Dairy intake
and increased risk of prostate cancer, but what's almost never mentioned is that there's also a link
between Dairy intake and other types of cancer, specifically breast and colorectal, but in the
opposite direction, so people who consume more Dairy tend to have lower risk of those specific
types of cancer. in fact, if you look at the guidelines from the American Cancer Society,
there's no specific recommendation for dairy in either direction, recommending or discouraging,
precisely because the data on cancer is mixed. so I'm not a big fan of this type
of communication where you tell the public one side of the coin, you don't show them the rest,
I'm not sure how this is empowering or how this helps people make educated decisions.
let me address real quick why I think this is so dangerous and so counterproductive, because I
know what the psychology is, I've heard this many times and I know we're going to get some comments
below saying, hey they're getting people to eat a healthier diet, why do you have to attack these
people? why do you have to nitpick so much? first of all, it's really ethically dicey to try to get
people to do something by selectively showing them facts or by stretching things and giving
them inaccurate information. that's shady enough as is. but even if we leave all of that aside,
this tactic backfires massively. when people realize that some of the information is inaccurate
or incomplete, kind of selective, they just dismiss the whole thing. most people don't have
the time to go investigate each Topic in detail, that's why they're watching a documentary, so
they're going to lump everything together. and can you blame them? I don't. so they hear about the
Stanford randomized trial with twins, oh, that was in the same show that also made those exaggerated,
unreliable claims about Dairy, so maybe that's all bunk. oh, that same show also brought up climate
change so maybe that's entirely a hoax. right? it taints everything, it's like it's radioactive.
and lastly, I'm almost done with this rant, okay? everybody else is going to use the same
Playbook to sell every diet on the internet, every supplement, every Wellness fad. things that you're
going to find are really dangerous and really questionable but you're not going to have any
moral authority to criticize if you supported the same tactic when it was applied to the diet that
you happen to like, so the only path is to point this out when it's done, regardless of which diet
is being talked about or which influencer, if we like the person or not. statements are
either backed by the evidence, they either reflect balance of evidence or they don't. if they don't,
it's not the end of the world but we improve, we make things more accurate. and that goes for
everybody, it goes for me as well. okay, end of the rant, back to the show. on a positive note,
the show features many important issues around food beyond just the aspect of nutrition, like
contamination issues in factory farms, widespread antibiotic use and the consequences of that,
and also the climate impact, which I agree is hugely important to learn about. I'm not a climate
scientist, that's not my training, but I do try to read up on this topic as much as I can and I
try to talk to people who do it professionally, we have a couple of videos previously on this topic,
and it does look like there is compelling evidence that the way we produce foods, the food system,
needs to change if we are to get climate emissions under control. it's absolutely about fossil fuels,
that's a huge part of the puzzle but it's also about how we produce our foods,
and actually these two sectors overlap so it's about all of it. the show also features some
great social efforts like organizations trying to fight food deserts by growing and providing fresh
vegetables for underprivileged communities. one really interesting thing about the show is they
go over a lot of different experiments that were carried out in the Stanford study, and it looks
like that publication that we featured recently in a previous video is just the beginning, there's a
lot of interesting experiments that haven't been published yet and I'm sure will come out in the
future. so for example the effect of the two diets on the microbiome, on cognitive function,
so brain function, on the rate of aging and also on body composition including visceral fat. they
do mention some of the flashier results on the show so we're going to touch on that briefly so
spoiler alert, if you haven't watched the show yet we are going to Spill the Beans a little
bit here. of course in order to properly evaluate this we're going to have to wait until things are
peer-reviewed and published so we can actually go through methodology and results, that's absolutely
essential, anything that's mentioned on a TV show in passing we have to use a huge grain
of salt. so in terms of body composition, this ratio of fat lost to muscle gained, it looks
from the show like at least in some twins this ratio was more favorable on the omnivore diets,
so it'll be interesting to see if that pans out in the actual full set when it's published, and
also I imagine this will hinge on the details, how much resistance training was each person doing,
protein intake, as we saw in the video previously the vegans in average were getting less protein,
and substantially less, so that's an obvious thing to bear in mind when we're talking
about body composition. they also had a more novel, a more original experiment in there,
and that honestly seemed tailor made for a Netflix show, they had the participants watch porn,
and as they were doing it they took pictures of their genitals. I am not kidding, they
actually did this, and they use those pictures to assess the temperature of their nether regions,
so they're kind of gauging the blood flow to those zones so it's a measure of arousal, really. now,
it looked like only the female participants went through this specific experiment,
there's probably a technical limitation where you can't tell temperature differences in males maybe.
or maybe the males were always aroused so you can't tell the difference. all right, it's been
real everybody, I think I'm getting canceled. it looked like all of the females improved, there's
more blood flow after the experiment, after the 2 months, the investigators suggest that this is
because they were all exercising, that's certainly possible, also they were all on diets that are
pretty clean, probably better than the diets they were on before the trial so that's another
possible explanation. and it looked like the twins on the vegan diets improved even more. now,
they only showed two pairs of twins so we really can't make anything of it but it'll be interesting
to look at the published results to see if anything pans out. in terms of cognitive function,
they had the twins go through some tests, some puzzles, some memory tests, things like that,
and they did not detect a statistically significant difference between the two diets
by the end of the study. the researchers suggest that this might be because the participants are
pretty young and cognitively normal, they look like they're mostly in their 30s and 40s so
maybe if you look at an older population that's starting to decline a little bit cognitively,
maybe you'll pick up something. and then in terms of the microbiome, they did detect significant
differences. I think that's more expected, we know the microbiome can change rapidly with diet, so
for example the twins on the vegan diets had more bifidobacteria in their microbiomes. generally in
the microbiome literature bifidobacteria are seen as health-promoting bacteria but in this concrete
case, does this margin, this difference that they detect result in any actual health improvements,
any health advantage? TBD. we'll see, again, we'll look at the published data. and then these
experiments on the biological clock, this has been one of the most touted results of the study,
so they actually measured the telomeres of the participants, so telomeres are the caps,
kind of the ends of chromosomes and in general as we age telomeres get shorter. so they used this
as a surrogate of the rate of aging and they did observe a statistically significant difference,
the vegans had longer telomeres by the end of the experiment. pretty curious finding,
a little surprising because it's something that we tend to think about as a more long-term parameter,
but interesting, it'll be interesting to see also what, if any, health implication this has,
and I also also wonder, if this does pan out, what is it about that group that elicits this
difference, is it really something about the vegan diet per se? is it the weight loss? as
we saw in the previous video the twins on the vegan diet lost more weight. or is it something
else altogether? and then other metrics like LDL-cholesterol and fasting insulin,
those were lower in the vegans and we covered that in the previous video. in general,
when I'm watching a movie or TV show, even if it's a based on true events movie or a reality show,
I'm always aware that it's fundamentally entertainment. it's fine to watch, it's fun
to watch but it's good not to forget it needs to be captivating for a general audience, it needs to
have a storyline, it needs to have a beginning and middle and an end and kind of wrap nicely,
so at the end of the day there is no substitute for looking directly at scientific data and we
covered the published results of the Stanford twin experiment in a recent video and I'll link that
right here. and I also reviewed another Netflix show on diets called The Game Changers a few
years ago, actually, and I'll link that right there. check those out, I'll see you next time