a brand new study just came out comparing a ketogenic diet and a mediterranean diet,
it's called keto-med (appropriately) and it's led by christopher gardner's lab at stanford.
the main question they were trying to answer was, which diet is best for people with diabetes
or pre-diabetes? both diets were designed to be clean, meaning that the participants were
asked to avoid junk food, refined grains and added sugars, and both included non-starchy vegetables
like leafy greens. the main differences were, the mediterranean diet included legumes, whole fruit
and whole grains, while the keto diet avoided most of those foods, except for maybe some
berries. the mediterranean diet also had plenty of olive oil, characteristically,
and the main animal product was fish, whereas the keto diet had more animal foods like meat, eggs,
cream etc. now, the macronutrient breakdowns were approximately 18% protein, 39%
carbs and 45% fat on the mediterranean diet, so fairly typical, and on keto 24% protein,
12% carbs and 62% fat. now, i already know there's some viewers saying it's not low carb enough,
because every time we make a video about a trial that's either low carb or low fat,
regardless how low they go, there's 50 comments saying wasn't low enough. joking aside,
it was actually pretty solid, the people on keto were asked to stay under 50 grams of carbs a day
and they actually averaged 43, and they actually had an objective measure of ketosis, they measured
the level of ketone bodies in the blood of the participants. they asked them to try to stay above
0.5 millimoles per liter and most of the time they succeeded, they were between 0.5 and 1.5 which the
authors consider light ketosis, above 1.5 being optimal ketosis. we can compare this for example
to the virta study, which is a study run by a company that specializes in low-carb diets and
it's actually overseen by some of the intellectual leaders of the low-carb/keto movement. in Virta
they were also shooting for ketones above 0.5, same range as the keto-med trial we're looking at,
so that seems reasonable. in Virta the participants stayed in average right above 0.5
for the first six months, by one year most were under 0.5, so no longer in ketosis technically,
and by two years only 14% were in ketosis. now, Virta is much longer than keto-med but
even early on they were right above 0.5, just barely making it into this light ketosis range,
so it's just difficult to get people to adhere to these strong elimination diets,
this is not specific to low carb. we had a recent video where we looked at a trial
comparing mediterranean to a diet they called low fat and we saw that they had a really hard time
getting the participants to significantly cut back on the fat so this is just something we see
consistently. so the issue is always that you're not dealing with mice in cages so there's a limit
to how much experimental control you have. on the other hand, when we're just choosing a diet for
ourselves, this aspect of populational adherence matters much less, the only factor is whether
you can stick with it it, doesn't matter how many other people can do it. okay, back to the trial,
so they looked at 33 people that were either diabetic or pre-diabetic, so it's not a large
number of subjects, so that's a caveat to bear in mind, although they used what's called a crossover
design, where each participant goes on both diets sequentially, so in a way you get double
the amount of data. so each participant went on one diet for 12 weeks, then the next diet for
another 12 weeks and finally 12 weeks of follow-up where they didn't get any dietary instructions so
they could eat what they wanted, and the order was chosen at random so approximately half of
the participants did the keto diet first and then the mediterranean, and the other half
did the mediterranean first and then the keto. the main parameter they were interested in,
what's called in nerd speak the primary outcome, was glycated hemoglobin or hemoglobin a1c,
as it's also known, and that's an average of the glucose levels over the previous three months.
both diets lowered hemoglobin a1c compared to the baseline, right before the experiment,
and there was no significant difference between the two. now, honestly when i read that at first
it was surprising to me, i expected both diets to generate an improvement but i thought keto would
have an edge. in type 2 diabetes the carbohydrate processing machinery is sluggish so there's two
things we can do, in the short term we can avoid excessive or supraphysiological glucose peaks
while the machinery is still defective. that doesn't solve the underlying issue but it
avoids a problematic manifestation. the other thing that can be done is to fix the underlying
issue so the machinery works normally, and the main lever to do that shown in randomized trials
is to moderate overall caloric intake and to lose a little bit of the excess fat mass that people
tend to carry, we covered all of this in a recent video where we talked to professor roy Taylor, a
diabetologist from the UK. so any diet that helps with weight loss can help with the function of
the machinery, with the underlying issue, this is why a lot of times you'll see some people saying
"a low-fat diet reverse my diabetes" and somebody else says "a low-carb diet reversed my diabetes"
or "a vegan diet" or "a paleo diet"... they're not lying, the common theme is they all eliminated our
moderated ultra processed foods, calorically concentrated foods, so that helps moderate
overall caloric intake. so i expected both diets to deliver a benefit because they're both clean
diets, they're both low in ultra processed foods, and i thought keto would also help moderate the
postprandial glucose peaks in that initial phase while the underlying machinery is still sluggish,
just because there's less glucose being eaten, and in fact diabetes is one context
where there's quite a bit of data showing that low carb diets can be a valid tool to help
with glycemic control. yet overall, the results showed no statistically significant difference
between the two diets, but i think when we look a little deeper it does suggest a difference. see,
in order to avoid hypoglycemia, in order to avoid their glucose levels from crashing too low,
the participants who were on glucose lowering medication were asked to reduce it before getting
on the diets. now, that's pretty standard in this type of dietary intervention trial, the problem
is the participants who were about to go on the mediterranean diet cut their medication in half
while the ones that were about to go on the keto diet completely eliminated it, so it's possible
that the drugs that were still left helped the mediterranean diet perform a little bit better,
push the glucose a little bit lower, whereas the people on keto didn't have this extra
help. to the investigator's credit, they ran a separate analysis where they matched for a dose
of glucose-lowering medication, and when they did that, the results do suggest an edge for
keto being able to lower hemoglobin a1c a little bit more than the mediterranean diet. now, the
numbers of participants in that analysis are very low so we have to be cautious, but the results do
suggest somewhat of an edge. they also asked the participants to wear a continuous glucose monitor,
which looks at the dynamics of glucose levels over the course of the day, and here again they
saw that both diets improved glucose control, with keto performing a little better. so overall,
both diets clearly beneficial compared to baseline and the results indicate that the ketogenic diet
may have an edge with regards to glucose control, at least in this time frame, and remember,
the participants were in light ketosis, so it's possible if they were in deeper ketosis the
results would have been even stronger. possible. the researchers also looked at blood lipids,
and this was interesting, the ketogenic diet was better at lowering triglycerides but it was worse
for ldl-cholesterol. now, that's a pretty common pattern in low carb trials but it's by no means
a necessity, and we'll come back to this in a minute. they also looked at body weight. both
diets delivered weight loss, it seemed like maybe a bit more on keto, it wasn't completely clear,
if you remember, it was a crossover study, people who did keto first did lose significantly more
weight than people on the mediterranean diet but the people who did keto second,
there was no significance there, so it wasn't completely clear, there's a bit of uncertainty,
but for me looking at it, it does look like there's a trend for keto to lose a little bit
more weight. now, ideally we'd want to know body composition, how much of the weight is actual fat
mass versus lean mass, we know for example that with low carb diets it's common to see early on
a loss of glycogen and water, so we want to know how much of the lost weight is actual fat mass,
but those details were not reported. and finally, they looked at what the participants chose to eat
in that follow-up phase when the pressure is gone and they get to choose, and they found
that they generally gravitated more towards a mediterranean-ish diet and not so much
a low-carb diet. and the researchers suggest this indicates more sustainability long-term or maybe a
higher personal preference in default conditions. so bottom line, i really like this trial, it shows
us clearly that each diet had something to offer and neither one was perfect, mediterranean lowered
hemoglobin a1c but keto probably lowered it a bit more, and it was better for cgm parameters,
but it was worse for cholesterol, mediterranean was better for cholesterol, but keto was better
for triglycerides and mediterranean might be a bit more sustainable long term. now, at face
value we might think, okay so i just got to pick one diet and compromise on the shortcomings,
but i think this trial and all the evidence we've been looking at lately
are giving us a much deeper and much more empowering message, that we can tailor our
diet to our needs using different features from all these different dietary patterns,
that we don't have to compromise on health, and we shouldn't. let's say i prefer a low carb diet and
i'm actually one of the people who can sustain it long term and i do well on it, do i have
to expose myself to high ldl-cholesterol, am i stuck with that? no! in this trial, people
on keto were eating twice the saturated fat of the mediterranean diet and half the fiber, they ate as
much fiber as the average american on the standard american diet so it's entirely predictable that
their cholesterol would go up, but it's completely doable to design a low-carb diet, even a ketogenic
diet, with more fiber, less saturated fat and more unsaturated fats, and there's lots of precedent
for this, studies have shown a low-carb diet rich in unsaturated fats helps lower cholesterol,
not increase it, so this general idea that low-carb diets jack up your cholesterol and that's
something you just have to live with is not a necessity at all, it's basically a misconception.
i've been saying this for like two or three years now, i have old videos where i go over this. real
quick aside, ldl-cholesterol is a marker of apob lipoproteins that carry cholesterol, and high apob
raises cardiovascular risk, the evidence on that is abundant and unequivocal, we've covered that in
a lot of previous videos. as far as the different types of fat, saturated fat generally refers to
fatty meats, butter, coconut oil etc and unsaturated fat, it's things like nuts and seeds,
fatty fish and most vegetable oil. okay, but maybe there's a disadvantage to unsaturated fats,
maybe they're better for cholesterol and for cardiovascular risk but they're worse
for triglycerides or glucose, and maybe it's a trade-off? we actually have trials comparing
different keto diets, same proportion of protein, fat and carbohydrate, just different types of fat.
high saturated fat keto versus polyunsaturated fat keto, and what this trial found was that
people on the poly unsaturated fat ketogenic diet had lower cholesterol, that's not surprising,
but also lower triglycerides, lower glucose and better insulin sensitivity. the authors concluded
"a polyunsaturated fat ketogenic diet may be superior to the classical saturated fat
ketogenic diet for chronic administration". so yes, you can get the best of both worlds.
and speaking of chronic administration, this is another caveat that always has to be brought up,
we don't know what happens long term on very low carb diets,
five years, 10 years, 20 years on 10 or 5 percent of calories from carbs, what happens to disease
incidence rates. low carb diets have been around for 100 years or more but we don't have cohort
studies with reasonably matched populations over the long run. i'm sure those studies will come
eventually, until then it's a bit of a question mark. it doesn't mean people can't do the diet,
it's just something that we have to bear in mind. okay, so the keto diet is completely optimizable,
the exact same thing goes for the mediterranean diet, if i'm on a mediterranean diet and i like it
but my triglycerides or my glucose aren't quite where i want them, nothing stops me from tweaking,
from for example taking a percentage of the whole grains on my plate and replacing that
with some unsaturated fat or some protein, that could be nuts and seeds, some legumes, some fatty
fish... so understanding these simple principles allows us to fine-tune our diet to fit our needs,
whether it's low-carb, high-carb, intermediate carb, without having to go through these
whiplash changes from one extreme all the way to the other. we marry the science with the
individual circumstances to personalize and give the person the best odds, right? we don't ignore
individual circumstances and we don't ignore the science either. and as we said, avoiding
the glucose spikes doesn't necessarily mean the underlying issue is resolved, I could still be
insulin resistant and diabetic technically and just not see the manifestation if there's
no carbohydrate challenge to the system, so for type 2 diabetes, bearing in mind for most people,
losing a little bit of that extra fat mass is going to be beneficial, so whichever diet keeps
you satiated and is sustainable long term is going to help you achieve and maintain a healthy body
weight and improve your glucose metabolism. some people do better on a low carb diet,
some on a low fat diet and someone neither. we see this individual variation in studies and i hear it
every day from you guys in the comments, so it's crucial to give people some options,
some healthy options, so they don't have to fall prey to crazy fads, the all-bacon diet
or the rice and sugar diet, just because those help lose weight. and yes, both of those are
real things i've seen on the internet. the authors say it themselves: "there should be less focus on
promoting one particular diet as best and rather, allow patients to make an informed choice to help
them establish which approach is most suitable for them". a diet should not tie your hands. the diet
should serve you, not the other way around. i see people all the time struggling to stick to these
diets and compromising, "oh this diet is good for this but it's bad for that, oh well"... you don't
have to play that game, you don't owe allegiance to a diet, why shouldn't you take something good
from both sides if it helps you? in fact, people have already coined the mediterranean keto diet,
a blend of both. the internet can convey this idea that diets are rigid structures, there's
the low carb diet and the low fat diet and if you deviate, you're a traitor and a failure. these are
internet constructs, if your diet is giving you the results you want short-term and long-term,
optimizing your health overall and you like it, stick with it. if not, tweak it, change it. yeah,
you can have your cake and eat it too. even if it is a low carb cake. so what are your thoughts on
this trial? did it give you some new ideas? let me know below, take care, see you next time, bye