so a lot of you asked about eggs and cholesterol. there's a lot of confusion
around eggs so in this video we're going to focus
only on whether they raise our blood cholesterol levels or not. if you have
other questions let me know. everybody knows eggs have a lot of
cholesterol but does that mean eating them raises my cholesterol levels?
that's a different question. just because a food has a lot of a
certain nutrient doesn't necessarily mean
that it ends up in my bloodstream. we have to test it directly. scientists asked
college students to eat a large egg every day
for three weeks. those poor college students are always the guinea pig.
after the experiment they ended up with higher LDL-cholesterol
that's the bad cholesterol although i don't really agree with those nicknames
we covered that in this video. okay, but maybe the students didn't
follow the instructions or maybe they ate some other junk that
raised their cholesterol levels. who knows
you can't trust those college students. so we need to confirm
what if we could give people eggs and then swap them in and out without them
even knowing it? impossible? some nifty scientists figured out how to do it
they gave people egg or egg substitute. indistinguishable taste but
four times less cholesterol. start people off with eggs for four weeks,
their blood cholesterol level shoots up. switch them to the substitute,
their cholesterol drops. do the experiment the other way around,
start them off with the egg substitute for four weeks, cholesterol goes down a
bit from their baseline. switch to real eggs, cholesterol shoots
up. and that's double blind, so the volunteers didn't really know if
they were eating the real eggs or not and even the experimenters didn't know
until the end of the experiment when everything got analyzed. we've also had
confirmation in massive analyses of large numbers of
rigorous studies that eating more cholesterol tends to
raise our blood cholesterol levels. okay, so if there's this much evidence
how is this such a controversial topic? normally these confusing ideas about
food floating around on the internet that have people
pulling their hair out they're not plucked out of thin air because that
wouldn't stick. they're usually rooted on a nugget of
truth. so what's the nugget? the nugget is that the effect of food on
our cholesterol level depends on context. if your cholesterol levels
are low, the more cholesterol you eat, everything else being equal, the higher
your blood cholesterol level will tend to go
but as you get to higher blood levels the effect peters out
this is true of many other physiological parameters, it's not specific to
cholesterol. our blood pressure doesn't keep going up
infinitely in a perfectly straight line as we eat more and more salt. our blood
sugar, etc. there's usually a ceiling effect at
high levels. okay, so now that we understand this
dynamic we're in a position to understand where the confusion comes
from. let's play a game called science twister
let's say i want to prove that eating eggs does not affect my
blood cholesterol levels. how can i design the experiment to get
that result? pause the video if you want to think,
we're going to go right into the answers. there's actually several ways to twist
things and win this game. the most obvious one is to stick to this range.
take someone who already eats a lot of cholesterol, typical western diet,
and who already has high blood cholesterol levels
and ask if adding a little bit more in their diet makes a difference. probably
not. another way to twist it is to compare
the eggs to another food that also raises
our blood cholesterol levels, like red meat or butter, something with a lot of
saturated fat. this is why the reductionism is so
confusing, focusing on single nutrients. my blood cholesterol is
affected by the cholesterol i eat, sure, but also by the saturated fat i eat,
the unsaturated fats, the fiber, etc so
always be wary of confusion around isolated nutrients
out of context. here's another strategy to win at science twister:
this one is like the ultimate, like the jedi level mastery
these researchers acknowledge that LDL cholesterol goes up with eggs
but they argue that's fine because HDL cholesterol also goes up
except that if you saw our LDL and HDL video you might remember
that study after study has shown that raising HDL cholesterol levels
doesn't really affect heart disease risk. so this argument that one
makes up for the other, that they compensate for each other, is not
general, there's some context and some nuance,
fine. what we want is the bottom line. is it okay to eat eggs or not? here's an
example: individual A is in good health, good body weight, great
cholesterol levels, and he or she eats an egg here and there
because he likes it. individual B has lipids that are out
of whack, high cholesterol and eats five eggs every day because he
thinks he needs the protein. clearly this is night
and day, the first case i don't see a problem
and the second case could do a lot. better now admittedly these are
extreme cases, a lot of people are going to be somewhere in the middle,
but you get the idea, these dietary decisions
factor in our health, our lipids our family history, our personal
preferences... so are eggs good or bad? depends what you compare them to and
your circumstances. eggs are not necessary
and they're not this magical protein source that we can't do without so
if you'd rather not eat eggs that's completely fine but it's also
not true that if your diet includes some eggs that it's automatically unhealthy
can they be a problem in certain contexts?
sure. we just saw case B where that person is unnecessarily jacking up their
lipids. but we also saw case A that was very
different. there's this tendency online to oversimplify
everything. everything, every food has to be good or bad,
everything is turned into a soundbite and it just confuses people
every time i do a video on a given food and i go over the results and i try to
explain areas of nuance somebody will pop up in the comments and
say that i'm an industry shill because i'm not outright blanket
condemning the food or i'm fence-sitting for views or money
we're so used to food being classified in soundbites
that unless we say the food is perfect or evil we must have some agenda
personally i avoid eggs, i don't think they would add anything to my diet
but that doesn't mean we're going to make stuff up. at the end of the day
it's less about specific foods and more about overall dietary pattern. a diet
high in saturated fat and cholesterol will tend to raise your blood
cholesterol levels, with or without eggs, and conversely a
diet high in fiber and unsaturated plant fats will
have the opposite effect, even if you sometimes
eat eggs. now, people often ask about egg whites. we
have a lot less evidence on those but yeah
in all likelihood they won't raise your cholesterol as much because the fat and
cholesterol fraction is missing. that said, in my experience
when people ask about egg whites it's often coming from a place of
believing that we need massive amounts of protein
and that it's really hard to find and so we need very specific protein sources
like eggs to get all the protein we need. and for
the vast majority of us that's not true at all
protein is everywhere and most people in the west
are already getting all the protein they need and then some
so if you eat some egg whites here and there because you enjoy them
and you're a healthy person i don't see an issue but if you're
slamming egg whites with abandon as a staple
source of protein because you're stressing out about not getting enough
protein chances are you really don't need to. we
have this protein fixation in our society that's
way off and not really conducive to optimal health
in this video we look at LDL, HDL and what it all means. and this one looks
at protein. where to find it, best sources and how
easy it is to get all the protein we need