what time do you eat dinner? the answer could determine your health. time
restricted feeding is a type of intermittent fasting where you eat
within a time window. the most popular 16-8: eat for eight hours, fast for
sixteen. in the last video we looked at fasting for 24 hours or more like
alternate day fasting or 5/2, where people fast two days a week. we were
trying to figure out two things: number one, can intermittent fasting deliver
benefits? it clearly can. weight loss and many metabolic benefits that come
with it. and number two, are those benefits unique
to intermittent fasting? because that informs our decision. if the benefits are
specific then we should all be fasting and if we're not, we're leaving benefits on
the table. but if they're not unique, if I can get the same benefits with another
method of weight loss or calorie control, then intermittent fasting is another
viable option on the menu. human trials comparing fasting to other methods of
calorie control by and large show a tie. similar weight loss, similar metabolic
changes. so that's saying intermittent fasting is another viable option. if it
works for you, if you like it, fantastic. if not, you have other options. whether
it's low fat, low carb, low calories, high-fiber, for weight loss they all work.
now, time restricted feeding is different. as we'll see today, what time I eat my
meals has a unique effect that is not explained just by calories. many of you
also asked about autophagy. our cells start digesting themselves
when we're starved, that's called autophagy. in mice fasting has some extra
benefits that aren't easily explained by calories or weight loss and autophagy
seems to be involved. but in humans as we just said, we don't see those extra
benefits. humans have autophagy but we don't know if it causes any of the
benefits of intermittent fasting. it's extremely difficult to prove that
experimentally. so it's an interesting discussion but for practical purposes it
doesn't change much. and the whole point of these videos is to be practical and
straight to the point. that said, autophagy has become a
buzzword so I probably should have brought it up just to clarify why I
don't think it's central, because people are gonna be wondering about it anyway
lesson learned. several people also asked 'why don't you talk about appetite and
hunger?'. because some studies report more hunger on intermittent fasting and
others don't. it probably varies between people. some people do better on it than
others. if you feel good on it, if it helps you lose some extra pounds, great!
by the way, I love the intelligent disagreement. critical
thinking is the whole point of these videos, so by all means keep it coming
okay, so that's fasting for 24 hours or more
what about meal timing within each day? the so called 'time restricted feeding'?
when people restrict their eating window, like the 16-8, they tend to eat less
overall and lose weight. that's a good thing if you have some extra weight to
lose. so again, valid weight loss strategy. now, are the
benefits unique? does time restricted feeding offer benefits beyond just the
calories and weight loss? same question we asked earlier. yes, it seems it can.
people eating the same calories at different times of day showed different
benefits. one group had their meals at what most of us would call normal times
breakfast in the morning lunch in the middle of the day and dinner in the
evening the other group had the same exact three meals but all concentrated
early in the day. they were done with their dinner by 3:00 p.m. the early
eaters had several metabolic benefits, like lower insulin, blood pressure and
less oxidative stress. so this is different from last video with the
24-hour fasting where we saw that the benefits generally tracked with the
calories. here we have people eating the same foods, the same calories, just
different times, and getting different results. this is a sensational finding. in
fact, when the first studies came out showing this, I didn't believe it. I
thought it was an artifact. but then more studies kept coming out with similar
conclusions so I did what any scientist has to do when faced with enough
evidence: I changed my mind. what we eat is crucial but when we eat it seems to
be a factor as well. I'm so impressed I'm on a 16-8 myself except I eat for 16
hours and fast for 8. and the eight hour fast happens to coincide with my sleep...
still counts! ok hold on a second, this is a little
confusing. the benefits of fasting for 24 hours are all about the calories but
fasting for 16 hours gives us benefits beyond just calories and weight loss? huh?
how can that possibly be? well, fasting may not be the key factor
in this study both groups ate their meals at "normal times"
breakfast in the morning lunch in the early afternoon and dinner in the
evening. both groups had the same total calories over the course of the day but
one group had more of their calories at breakfast while the other had more at
dinner. the people eating the big breakfast had better
glucose metabolism and felt more satiated than the group eating the big
dinner. they even lost more weight. that's insane!
they ate the same amount of calories they fasted the same amount of time and
yet one group lost more weight just by distributing their calories at different
times. now, some people might see this result and go "oh so calories don't
matter". let's not make that mistake. calories matter enormously but they're
not the only factor. calories being equal, having them earlier in the day seems
beneficial, even without fasting. so these are stunning results. the idea in this
field is that our circadian rhythm makes us better adapted for eating during the
day and a bit metabolically handicapped late at night. they call it early time
restricted feeding, this idea that we're better off avoiding stuffing ourselves
late at night. to be completely honest with you I suspect in the end it won't
be quite this simple. I've seen studies that don't really conform to this
perfect simple picture, for example this trial of early time restricted feeding
made some markers worse, like cholesterol levels. what I think is going on is it's
still a very young field, a lot of these studies are 2018-2019
so we're still trying to figure it out. I think circadian rhythm probably does
play a role, there's enough studies that I'm persuaded it's a factor, and I
suspect there are other factors as well. for example our genetics. some of us are
morning birds and others are night owls. I'm a huge night owl. and this isn't just
a habit. our circadian rhythm is determined by our genes. this was first
discovered in the 70s by my PhD advisor, the late geneticist Seymour Benzer. he
wasn't my advisor in the 70s, I wasn't born most of that decade and they kind
of like you to already be born when you apply it's kind of a prerequisite for...
what am I talking about? so to summarize what we know about intermittent fasting
and time restricted feeding: fasting clearly can help us lose weight, no doubt
about that. with the metabolic benefits that come
with it. does it have additional benefits beyond the calories and the weight loss?
maybe not the fasting per se, but meal timing seems to. shifting most of our
intake earlier in the day, having an early dinner or a light dinner seems to
provide benefits beyond just the calories and the weight loss, at least for
some of us. when it comes to food, *what* may be the star of the show but *when* is
a talented supporting actor. coming up, we'll tackle the Olive
Oil controversy. ruffling feathers every week here at nutrition made simple. in
the meantime, check out this video on how to get rid of junk foods and here's the
one on longer forms of fasting from last week. check it out
what time do you (blrrr) I need a haircut