– Hello and welcome to a
very special edition of GCN’s How To… with
Professor Asker Jeukendrup, who has very kindly agreed to give us some of more of his time after
we did that ask with him. And we got loads of questions
from people on how to really personalise their nutrition
for their particular problems. Professor Jeukendrup, thank
you very much for having us in your beautiful office again. – Thank you for having me. – I’ve mentioned before your
numerous achievements, but you’ve worked in the field
of sports nutrition and performance nutrition and
exercise science for many years. And I know that you’ve worked
with some very high level sports teams in football, cycling. You’ve worked with Chrissie Wellington, Haile Gebrselassie, tell us
a little about your role in with high level athletes, advising them in nutrition I think. – I think it’s a relationship
that works both ways. So I listen carefully to
what elite athletes tell me and then they tell me
what their problems are. And those are things that
we’ve taken to the lab, to try and find the answers. And then hopefully, I can then
help them with these answers. And that’s how I’ve
worked for many years and indeed I had the opportunity
to work with a number of great athletes and I have to
say that I have learned a lot. I hope that they learned a bit as well. – Yep and I think they have, but you should know that
Asker’s also himself a very keen triathlete, cyclist, runner, so he knows about the user end
of sports nutrition as well. So anyway, let’s get down to business. We had quite a few
questions from people who wanted to know about
nutrigenomics and whether they should go out and get DNA
testing to find out precisely what they should be eating in their event. So we thought we’d come
and ask you about that. – [Asker] Yeah, alright. – [Interviewer] So, can you tell us about what you think about that to start with? – Yeah, I think first of
all, I think personalization is the future in this field. For me there’s no question about this. Every individual is different
and we need to address that. Nutrigenomics has been suggested
as a solution for this, for this problem where you measure genes and then out of
that roles some advice. And I think some of that
comes from the medical world, where we see a lot of this
where based on your genetic makeup you may or may,
yeah you may be prone to certain disesases or you may respond to certain medication. That work in the medical
field is all based on a very large number of studies. And also the studies
themselves are very large, sometimes 10,000’s of people
that were followed in time, some people that get the disease, some people that don’t get the disease and based on that you can see
then that certain genes send people in different directions. – But it’s a statistical correlation. – It’s very much based on
statistics so it’s probabilities. – Yeah. – And now in nutrtion we see similar, now this is not sports
nutrition now, but just in general nutrition we
see something similar. We have fewer studies there, but still the studies are very large. When we come to sports
nutrition there’s a little different picture because
there we have actually very few studies and the
studies that we have, they don’t have 10,000’s
of people, typically their studies have six or
eight or ten people at best. And it is very very
difficult to draw conclusions from those small numbers of
studies with small sample sizes to do a really complex question. – A similar problem to in
sport science in general where training protocols are
tested on quite small groups of people and it’s very hard
to generalise to elite level or to people in general. – Yes, that’s correct. – Yeah. So at the moment you’d
say that maybe a DNA test is not the solution. That it’ll tell you bam,
take this bar, this gel, and that carbohydrate drink, its more — – Yeah, I think there’s several
reasons why I think that that it’s not the solution yet. First of all, because the
field is, we have so few studies to base this on
and it’s too early days. But also, the real reasons
why you need to eat somethin’ to perform are probably not
so much dependent on genetics. – Yeah. – So for example, the exercise
intensity and the duration, the type of sport you
do determine much more what you need, then your genome. – So the reason that I
don’t respond the same way to bar x or gel y as my
friend does is more to do with how hard I’m riding or
what I’ve trained myself to eat as well. Presumably that plays a part as well? – Yeah. Or even what your goal is. – Yes. – Right, if your goal is weight loss or your goal is to perform tomorrow, you’re eating differently. – Yeah, that’s a good point, yeah. So there is, one should try to
personalise one’s nutrition, but maybe not based purely on DNA. – Yeah, that’s correct. And maybe in the future it’ll
start to play a bigger role. There are some examples where
maybe this is useful already, but it’s very very early days. – Yeah. – Like an example is caffeine. We know that some people are
much more sensitive to caffeine than some other people. That is, you can trace
that back to the genome. – Oh really? – You measure that. So that’s one of the few things that we can already do today. – Oh right, I thought that
I was not very sensitive to coffee because I drink too much of it. But it’s partly my genes, okay. (Asker laughing) It’s good to know. Given that there are all these
different variables about exercise intensity and goal and well just personal preference, can you tell me how we as
cyclists should go about planning our nutrition for
either training or racing or whether there’s some
interaction between those? – Yeah. – There’s so much information out there, feels like sometimes
there’s too much information from many different
sources and it’s very easy just to try and copy what
other people are doing. Where’s the starting point, do you think? – I think for me the
starting point is always understanding the sport itself. – Yeah. – What is it that determines
the performance in that sport? I think it’s almost going back to basics. – Yeah. – Like what is it in
this particular sport, that determines performance. In cycling for example,
that’s gonna be different, of course, in mountain stages
than it is in time trials. And so it really depends, but you have to go back to that basic. Once you have a good
understanding of that, I think the question to ask is okay. Now with your training, what
are you trying to achieve? What are your main goals? So that for me is the next step. And as I said earlier, if
your goal is weight loss. Your programme will look
quite a bit different than when it is purely to perform. So goals is next and then it is about what
timing are we talking about. Are we talking about the 24-hour diet? – [Interviewer] Oh, yeah. – [Asker] Are we talking about
what to eat before training? Are we talking about what we eat during? So that’s the other component. – So if we were to take say, a cyclist who’s fairly experienced but they’re taking on
a big event this year, for example like a long
sportive, let’s say five to seven hours long, a major undertaking. How would they go about knowing
how to time their nutrition? There are, I believe
there are guidelines for how much carbohydrates
someone should take in. if they’re working above a certain level for a certain amount of time. Especially if there’s a
key goal, is what to keep eating as much carbohydrate
as you can really. – Yeah, not necessarily. – Okay. – ‘Cause that depends
on what your goal is. – Yeah. – If what your goal is to
perform at your maximum. – Yeah. – The advice will be
slightly different than when your goal is to reach the finish line. – Yeah. – And to complete the event. And if your goal is to complete the event, you probably don’t need as much. – Yup. – So that’s one factor,
the other factor is your absolute levels. – Yeah. – The power that your power
output is really important. So if someone produces 300 watts
versus 150 watts on average that’s going to be a different demand. – Yes, yep. – That’s important to
understand and I see a lot of, a lot of athletes who maybe take longer, who fuel the same that a
professional rider would do and that’s not necessary. – No, overdoing it on carbohydrate is an extra on the body
that it can’t cope with under high perform loads and
if you’re trying to digest and put out power at the same
time it’s not always a great. – Yeah, that is definitely a challenge. – Great, thank you. So, how would we go about
knowing about how much carbohydrate to take in, during an event? – We do have some guidelines for that and the amount you need to
take in probably depends on the duration of the exercise. So if it’s only an hour, two hours, you need smaller amounts. If you go over two
hours you need probably, say between 30 and 60 grammes
of carbohydrate every hour. – Yeah. – If you take this really seriously, your power output is high
and you’re goin’ over 2.5 to three hours, this
is where you may even think to go higher than 60 grammes per hour. – Okay. – And up to 90 grammes per hour. But, this is where it gets
a little tricky because your body can absorb, most
peoples bodies can absorb, up to about 60 grammes per hour of any type of carbohydrate
and so that’s not, that’s no problem. If you go higher than 60 grammes, then that may be a problem
in terms of the absorption unless you take the right
types of carbohydrate. – Okay. – So I would always advise, do not go higher than 60 grammes per hour. – Okay. – Unless you know about this. – Yeah. – And you know which
carbohydrates to select. – Yup. – The carbohydrates you
need to select to go higher. – Yeah. – Are a combination of
glucose and fructose. – Yup. – Or maybe maltodextrins and fructose. – And those are the easiest to absorb. – Yeah, so that combination, they and, the technical side of that story is those are two types of carbohydates that use different
transporters in the intestine. And if you only use one transporter, it just gets saturated and this is why you cannot absorb more than 60 grammes per hour. If you use the two transporters, then that means that you can
absorb glucose and fructose at the same time and we’ve
shown that you can then go up to even higher
than 90 grammes per hour. – So you’ve got like a
two lane road instead of of a one lane bottleneck. – That’s correct, yeah. – Thank you. What about, so we had
questions from people saying obviously that fat is much
more energy dense per gramme. So if you could, why not take
on 60 grammes of fat per hour and you’ve got way more energy. It’s not as simple as that
though is it in terms of absorption into the body. – No, it’s not. Unforunately, well there’s two issues with fat during exercise. One, is that the liver is very slow. – Yeah. – Whereas carbohydrate is
absorbed really quickly and is in your blood within minutes. And with fat that’s a different story. And this may take hours. So by the time the bulk of
the fat actually gets absorbed you may be done with your ride. So it’s not the ideal energy source. – More energy for the party yeah. – It’s not a problem to take a little bit of fat on during exercise,
but it’s not a good fuel. – Okay, thank you. And then I come to the question of what kind of carbohydrates. So you mentioned fructose,
glucose, maltodextrin. What about these energy
bars that are slow release, based on oats or I know
that obviously there are really different carbohydrate
chain links and that affects the absorption time. Personally, I really like
eating flapjacks and oat-based products, I have a soft spot for those. What do you think about
those and in sort of high intensity events? – [Asker] Yeah, in high intensity events, that wouldn’t be my first choice. – [Interviewer] Oh well, yeah. – In training and lower intensity
event it doesn’t matter. It’s not about delivering the
energy as fast as possible. But in high intensity events and races, this is where you want
to deliver the energy as quickly as possible. You also, at the same time,
you want your intestine and your stomach to be
as empty as possible. Because you want that, the
carbohydrate to go through that as quickly as possible. So you only get that
unfortunately with the… – With the sugars. – With the faster sugars. – And oats have too much fibre and protein and a little bit fat so
they slow the stomach too. – And often the products
that have them also, they have a little bit more
fat, little bit more protein, they are all things that slow
down the gastric emptying and thus the delivery of the carbohydrate. – And slowing down
gastric emptying can also lead to stomach cramping
I think if you have too much food just sitting in your stomach when you’re trying to
basically pedal hard. – Yes, that’s right. – I’ve experienced that for sure. – Yep. – It’s pretty unpleasant. – Great, thanks Asker. So we’ve got this rule of
thumb or general rule for how much carbohydrate
on average for an event when you’re working hard. But, in cycling events there
are obviously obstacles in that there are mountains,
descents, corners, you know maybe there’s
a sprint coming up or a place you have to be at the front or portions of the course where
you know you’re gonna be working very hard and then
portions when you’re not. How do we adapt our nutrition to fit into the practicalities of a cycling course? And that maybe sometimes
you just don’t have a hand free to eat anything? – Well there’s two things
you can do of course. You have to be very
clever with where you eat. So we can say that from a
laboratory it’s easy, right? So you can say, oh every
15 minutes you need to take on board something and that’s usually what we do in the lab. But, if you’re riding outside
and there are mountains and hills and corners it’s, it’s very tricky sometimes. It is important to think
about this beforehand. And in the work that I do
with professional cyclists, we do this, we sit down, we
say okay, this is the plan. This is what we need
to consume in the race. What are the best moments to do this? And they can usually tell me
where the best moments are because they’ve ridden those races before. And then we plan it out that way. The other thing that is imporatnt is that you do need to get to your
target of carbohydrate. But, we’ve also shown that
it doesn’t matter so much whether it comes from a
drink or a gel or a bar, but that it’s low in fat
and fibre and protein. So you can mix and match
and usually it means that in the early parts of races, for example, when the intensity is a little bit lower and you can still eat,
use more solid food. In the last couple of hours of races, it’s mostly gels because that only takes like a few seconds
to take so those are things that you can play with. So pick the right moment
and pick the right products at those moments. – Yeah, that’s certainly
what I would find, that I would study the
race course beforehand or nowadays maybe a
sportive course and work out where I’d have a hand
free to eat anything. So, not on the descent for me, but also I wouldn’t eat a massive
bar on the bottom of a climb where I was gonna go hard because it would come straight back up
again, which is not pretty. – Yeah, but you see that
people do make those mistakes. Sometimes just the beginning
of the climb is a time when you can actually eat
but then you’re still chewing when at the steep parts. – Yeah, you don’t wanna be
chewing when someone attacks and you’ve gotta go in
them, it’s very messy. Great, thank you very much. I know that you’ve
developed a way, a tool for athletes to plan their nutrition during events and during training, can you tell us a little bit about that? About what it’s called and how it works? – We call that programme
CORE, what CORE really is is that you have a sports nutrition scientist in your pocket. You can personalise
your own nutrition plan. What you get is all signs based, but also, at the same time based on you. It is also very practical
because it uses the products that you want to use. So you get a plan that is just bulletproof and you can go into your event
knowing that this will work. – When I used CORE to
plan my race nutrition, I actually wrote the plan on a bit of tape and stuck it on top tubes so that I knew, not that it was very
complicated, but it reminded me that at times of 40 I should
eat this and drink this. Or have consumed that by
then rather than on my go, it was really helpful. Thank you very much, this
was really interesting. I think that’ll be really
helpful for some of our viewers who have questions about how
to plan their race nutrition, their training nutrition even. So I hope that helps answer
some of your questions. If you would like to check
out some of Asker’s other huge knowledge on sports nutrition you can have a look at
this video down here where we put your questions to him. And a lot of questions about
personalised nutrition came up which we saved for this
video, but there’s lots of really interesting
discussions down there in that video.