Dr. Kevin Tiptonís Interview to Bodybuilders.gr
Sunday, November 15, 2009
YK: We have with us Dr. Kevin Tipton. Thank you very much for giving
this interview to us, www.bodybuilders.gr
KT: My pleasure.
YK: I should say first that Dr. Kevin Tipton is a Senior Lecturer in
Exercise Metabolism in the School of Sport and Exercise Sciences, in the
University of Birmingham, in the UK. His research focuses on exercise,
nutrition and muscle metabolism in humans. So, I will just start with
the first question: In your papers, you claim that protein needs for
people who exercise may not be that different than protein needs for
sedentary people. I quote from one of your recent papers that
"scientific opinion on this controversy seems to divide itself in two
camps: those who believe participation in exercise and sport increases
the nutritional requirement for protein and those who believe protein
requirements for athletes and exercising individuals are no different
from the requirements for sedentary individuals. There seems to be
evidence for both arguments." Does this refer to the least amount of
protein necessary for maintaining muscle tissue, in both cases? And if
so, is there such a thing as "optimal protein intake" for athletes (say
for optimal muscle gain or optimal fat loss)? And in this intake, would
you count ALL protein sources or only those of high biological value?
KT: Yeah, thatís a very good question. Definitely, there is a difference
between a protein requirement, which is by definition the minimum amount
necessary and protein recommendation for an athlete based on whatever
adaptation that athlete wants. So, if that athlete wants to have
increased muscle mass for example, then yeah, I believe that the amount
of protein that would be optimal for that is certainly going to be
different than the requirement. Remember the requirement is based on
nitrogen balance studies and the RDA (Recommended Daily Allowance). And
thatís established based on the minimum amount of protein necessary to
maintain nitrogen balance. So, the assumption is that nitrogen balance
is actually whatís important, and of course, thatís not what an athlete
is interested in. An athlete is interested in, you know, maybe itís
muscle mass, maybe itís speed, maybe itís something else, but that
wouldnít have anything to do with nitrogen balance, so yes, I believe
there is an optimal protein intake for each athlete, and thatís what it
is, itís for each athlete. And even within bodybuilders for example,
that protein intake could be different from one vs another.
YK: So, how can someone find his own optimal intake? Which are the
factors that affect this? And, again, does he need to count all protein
sources, including ones that are not very high in biological value?
KT: Again, thatís a very important consideration. Itís an extremely
complex situation and I guess my point is that if it is that complex,
youíve already identified several different factors which could
influence the response, the adaptations. So, thatís why I argue that to
say to a group of athletes, e.g. weightlifters, that they need to have
ď1.6 g/kg of proteinĒ is silly. And, as far as the way you phrased your
question, which is a good way to phrase it (ďhow to do thatĒ), itís not
entirely clear, but, as a practitioner, people need to do the best they
can to recommend the amount. Now, as far as what type of protein, I
think thereís probably evidence that you can support the notion that
animal-type of proteins, especially dairy proteins may have something to
them. I think there still needs to be more work to establish that for
sure. But, I think Stuart Philips studies this the last couple of years,
we also did a study on milk, and you start to see some evidence that
animal proteins may be superior to plant proteins. But, if your goal is
to get to a certain amount of protein, then yes, the protein in a tomato
is protein. Itís going to contribute amino acids. I mean, you certainly
donít want to skip that, you donít want to say ďthatís not thereĒ,
because it is, and those tomatoes, they provide a great deal of
nutritional value. Now obviously, thatís important as well. So, I think
that the fact is what your tomatoes or vegetables or something are gonna
offer in the overall scheme of things is gonna be a relatively minor
part, so those are really there for another reason. But, you certainly
canít ignore them as a protein source, itís protein.
YK: You mentioned that nitrogen balance measurements have been used for
a long time to define protein needs for sedentary people, and also for
people who exercise. Now, there are some people who think that itís not
a very accurate way for measuring protein needs, but itís more or less
itís like an indicator for the body's ability to adapt to a given dose
of protein. For example, this study by Tarnopolsky in 1992, where they
found that we have a nitrogen balance at around 1.6-1.7 g/kg/d RDA, but
they didnít measure any significant difference in muscle mass over time.
So, do you think there is a more valid way to estimate protein needs for
athletes other than nitrogen balance? For example, the 0.8 g/kg/d for
sedentary people has been extracted also from nitrogen balance
KT: Yeah, youíve hit on a couple of important points there. First of
all, there are definitely limitations to nitrogen balance measurements.
There are limitations to all measurements, but nitrogen balance does
have limitations. Now, let me back up. You are absolutely correct; the
RDA of 0.8 g/kg/d was established based on nitrogen balance. Markís
studies were also nitrogen balance studies. So, in a direct comparison,
like vs like Ė and Mark did extremely careful nitrogen balance
measurements, which are very very difficult to do, but Mark is a
fantastic scientist, so he did it absolutely right Ė so from that
standpoint, it seems that, you talk about protein requirements, maybe
they are a little bit higher for athletes, thatís entirely possible
based on those data. But again, do we really care about a requirement?
We want to know whatís optimal. And so you have to fit that within the
context of their overall diet, within their carbohydrate intake, and
within their total energy intake, and so there is maybe a gymnast for
example, whose energy intake doesnít support 1.6 g/kg/d. And maybe that
gymnast needs to have 1.4 g/kg/d, or something like that. So, I mean I
think you got to be very careful, and then the other side of that is
yes, nitrogen balance has its problems, and especially the higher you go
Ė as you alluded to this Ė the higher you go in protein intake, the less
you can compare the nitrogen balance to other intakes, because the
relationship disappears, as you said. There are several studies showing
nitrogen balance increases without changes in lean body mass. They donít
match. And also, if you look theoretically, and, you know, I can bore
you with some calculationsÖ
YK: Go ahead.
KT. Theoretically, in some of those studies, at the very high protein
intakes of 2.5 g/kg/d, that representsÖ, there are individuals in those
studies that were putting on 15 g of nitrogen a day. That translates to,
if you do the calculations, in theory that should relate to 100 kg of
lean body mass in a year! And obviously, thatís not possible. So, you
have to be very careful about interpreting nitrogen balance
YK: But, could the large amount of protein be a trigger for building a
more humanly possible amount of muscle? Maybe you need to eat 2 g/kg/d
in order to be able to build 10 kg of muscle per year. I mean, it
doesnít necessary mean that all the protein would go to muscle, but
maybe large amounts of protein are some kind of a trigger at some level,
I donít know what level.
KT: Thatís entirely possible, thereís no question, but thatís a
different issue. To put the two together, what you are saying, and what
I was gonna say, is that you canít directly interpret the nitrogen
balance. And thatís what people want to do. There may be a trend there,
and yes, there may be sort of a match at some level, but you canít
directly extrapolate the nitrogen balance, because thatís impossible,
itís physiologically impossible. So, I think you just got to be careful
about the interpretations. And then, you asked what about ďwhat would
you doĒ. Well, I think you suggested that, yes, ideally you put a very
large number of athletes on this protein intake, and a very large number
of athletes on that protein intake, and then you see which one has the
adaptation that you want. But, think about the necessity of controlling
those studies. The control that you have to have to get the sensitivity
of the measurement that you need. Because, what we are talking about
here isÖdifferences in small percentages. Very small percentages. And
the training stimulus is the majority of it, and what you eat is gonna
be a relatively small part of that.
YK: If I may ask a question on that: In bodybuilding, people are
interested mostly in lean body mass differences, right? They want to
increase their LBM. So, why havenít we seen Ė I mean I have never seen Ė
a study where, for example, you have three groups of exercisers, and you
have all three groups on a caloric surplus for, letís say, 12 weeks, and
then all these groups do the same training regimes, the same exercise.
And then you get each of the groups to eat a different amount of
protein. And then level out the rest of the calories. And you have the
same amount of calories in all three groups, but different amounts of
protein. If someone could carry out such a study, this would completely
end the controversy about if you need or not more protein.
YK: But, I have never seen such a study, I mean there are lots of
studies, I think that in the past people were not interested in doing
studies on bodybuilders and they would do protein studies mostly on
elderly people, or Ė I donít know. But, recently, there are studies
which are targeted on bodybuilders, soÖ
KT: Ok, there are a couple of issues there. One of the reasons that
there arenít studies on bodybuilders is because bodybuilders havenít
funded them. These studies are very expensive. But, the reason they are
on elderly is because government and others are trying to help elderly
people, they donít care about whether a bodybuilder wins or not. So, if
bodybuilders want these studies done, they need to quit sitting in the
gym and laughing at us about doing the other studies, they need to get
their money together and fund them. Now, more and more companies are
funding these things knowing that bodybuilders are indirectly funding
them through their supplements. So, more and more companies are
realizing now that they want to do weightlifting studies on
weightlifters. The original studies were all done in untrained people,
because you see the biggest response in untrained people. Itís the same
thing you were suggesting earlier about the fasting state. You see a
bigger response. You do that study first. If you donít see anything,
then you go away, you say ďok, that didnít workĒ. So, the next step is
then to do it on the trained people. And then see what the difference
is, if it still works. Now, as far as the longitudinal type of training
study you suggestedÖ
YK: Thatís a very typical scenario for many, at least recreational, and
then also some more serious bodybuilders. They do a bulking phase for,
say, three or four months, and then they gain fat at the same time, and
they say, ďok, maybe I should have eaten more proteinĒ.
KT.: Yeah, I mean, the bodybuilders I knew, and of course this was a
while back, but, they would do that, and then they would lean down, and
that seemed to work. Well, the problem is that, I bet you that in that
period of time, in those already well-trained guys, who already had a
very top response that the differences would be so small, that you would
need so many of them to see those differences, to make sure itís real,
rather than statistically random type of responses. Then, youíd also had
to control how much sleep they got, diet would have to be absolutely
controlled, and if we think that different types of proteins are
important, then we would have to control the type of protein, they all
would have to eat the same things, and people donít like to eat the same
things, and so then youíd also have to have whether they are
professionals or amateurs, if they are amateurs they are gonna have to
work, so, are they stressed at work?
YK: Yes, itís very difficult to isolate.
KT: The control of those studies is almost impossible to do properly.
And so, there are studies, that take people for 12 weeks and train them
and then give them different protein intakes, and there are some that
say that more protein helps, and there are some that say it doesnít. And
the reason for that is because of this lack of control. And, they are
almost all on untrained people to start out.
YK: I see.
KT.: So, itís a very very difficult thing to do properly, it may never
ever be done, because of the rigor that you would have to have. Put them
in a metabolic work, then they just stay there. But, thatís not a
real-life situation, so maybe that doesnít apply either. So, you always
have these issues that you got to account for. Thatís why itís such a
tricky thing to do. It may never be done. I mean, tell the bodybuilders,
if they want it done, to get their money together, and Iíll do it.
KT.: But, itís not free, you know! It costs a lot of money! Itís not
like we just sit there and think of these studies: ďOoh, thatís a great
idea! Letís do it!Ē. I mean, I just submitted 15 ideas to a funding
agency, saying ďhereís my ideas, do you like them, are any of these
worth your money?Ē. And thatís just partial about the ideas that I have.
I mean, the ideas are there. Thatís not the problem. And a lot of them
are the same things that you talked about, that youíve identified as
weaknesses in the literature. We see it, too. And weíd love to do some
of those studies, itís just that some of them you canít do, and some of
them you canít afford.
YK: I see, that sounds very interesting.
KT: Unfortunately, itís a practicality part of the science that a lot of
people donít understand is there. Now, science is so expensive,
especially these protein synthesis studies. I mean, the stable isotopes
that I use cost 500 GBP per gram. And, we just put in an order not too
long ago for 30,000 GBP. And thatís just one aspect of the study. For a
muscle sample, the analyses cost probably somewhere around 50-60 GBP per
sample. So, think of the muscle biopsies, and everything and then you
put it all together, and see youíre just talkingÖ
YK: A lot of money.
KT: Yeah, so a study typically is a couple hundred thousand pounds.
YK: No supplement company would ever fund that?
KT: Oh no, they do. Thatís where a lot of money comes from. But, weíve
got to convince them that itís gonna help theirÖand I am not gonna test
their supplement for them, I donít believe in that, I believe in testing
the science, what is this protein or that protein, what are the
differences, itís got to be a scientific question. So, you got to get
that of balance of some scientific question that they are interested in,
that they think they can use.
YK: Yeah. Ok, letís move to the next question. Hypocaloric state. There
have been some papers published where it is shown that definitely a
higher-than-normal protein intake would help in preventing lean mass
loss. In certain elderly women for example it has been shown, probably
in athletes too, I donít know, it makes sense up to a point. Of course,
maybe recreational bodybuilders already ingest this amount of protein
anyway. My question is, if this is true, can you use this information
for maintenance and for hypercaloric states in order to minimize the
muscle protein breakdown? Because, you mentioned that you have a muscle
protein synthesis period followed by a muscle protein breakdown period.
Would increasing protein in a diet attenuate somewhat the MPB? Because,
thatís what it seems to be doing in hypocaloric states. So, if you
consider that for the part that you have MPB, you are somewhat in a
hypocaloric state temporarilyÖ
KT: Ok, this is again a multi-layered issue. I will start with ďfunny
you should askĒ, because we just finished a study and itís gonna be
published in January, in weightlifters, hypocaloric, with high protein
vs a regular diet.
YK.: Oh, but I have seen I think, I am not sure, not in weightlifters,
but I have seen in normal peopleÖ.
KT: Yeah, thereíve been at least twenty to thirty studies in overweight
YK: But, in athletes?
KT: Yeah, well thereís one Ė sort of Ė back in the late Ď80s. Basically,
what we did is, we took weightlifters and for two weeks we put them on
60% of their normal calories, and they maintained their training the
KT: It was rough. Thatís a very low calorie intake and they werenít
happy. But, we monitored their activity very well, and so what we saw
was, one group was on a normal protein intakeÖ
YK: What is ďnormalĒ?
KT: ďNormalĒ was around 18% of their calories, and thatís what they
naturally did anyway, so we just kept it at the sameÖ.but just dropped
the calories, just dropped everything. In the protein group, we put
them, they dropped the caloriesÖ.
YK: Was this a low-carb or low-fat group?
KT: No, we substituted the fat, we kept the carbs.
KT. And I think that with athletes you have to do that, because if we
lowered the carb percentage, then they couldnít have done the training.
And thatís the difference, I think, between athletes and untrained
people, because their training wasnít at a high enough level that if you
dropped the carbohydrates it would hurt them. So, we kept the carbs and
substituted fat, and what we saw was very interesting. As you suggested,
there was less lean mass loss in the protein group. In fact, they
almostÖ,well some of them looked like they actually gained lean mass
despite the caloric intake. But, on average, they didnít lose very much,
whereas the other group did lose some lean mass. They both lost the same
amount of fat, and so what that meant was that the group that was on the
Ė sort of Ė normal diet composition, actually lost more total weight and
the protein group lost less weight, but it was mostly fat. So, the
lesson from that is you have to think about your athlete and you have to
decide what that athlete needs to lose.
YK: How much protein on the high-protein group?
KT: 35%. And that translates to about 2.2-2.3 g/kg/d. But, because the
calorie intake went down so much, it wasnít that high.
YK: But, does the amount of muscle lost for the low protein group
correlate with their initial lean body mass? I mean, common sense says
that, if you are a bodybuilder and you have a lot of lean body mass,
itís gonna be more difficult for you to hang on to it when you are
KT: No question, but the groups were matched for body composition. That
would be the difference between the results that you see in the obese
and overweight people vs the athletes, but in this case we matched it
for lean body mass. There is always some wiggle room in there, but I
donít think that was the major factor. Now, as far as the protein
breakdown side goes, we know for sure that, in almost Ė not all but Ė
unless itís a severe pathological state such as burns, or septic
patients or something, that muscle mass is lost because protein
synthesis goes down, not because breakdown goes up. Now, we didnít have
the money to measure the protein synthesis in that study. Thatís what I
want to do and Iíve proposed that and there is a ďnibbleĒ now to do the
next step, which is to measure protein synthesis, but I think that the
difference was that we maintained protein synthesis, not that we
ameliorated protein breakdown.
YK: I understand.
KT: Cause, even in states where if you immobilize someone and they lose
muscle as you do, itís not because protein breakdown goes up, itís
because synthesis goes down. And protein breakdown actually goes down
with it Ė when itís measured. So, I think that, that extra protein
probably was just maintaining protein synthesis better.
YK: Itís very interesting what you are saying. Next question: do you
think carbs are important around a workout? Cause several people tend to
avoid carbs, especially postworkout. They just only ingest protein,
because they donít want to attenuate fat loss, and so they want to have
both benefits, increased muscle protein synthesis and increased fat loss
at the same time, for a period of time. Would the insulinic response
from whey only be enough for stopping MPB? Because, it has been quoted
that we need carbs immediately after a workout only for the insulin. And
muscle glycogen restoration is something which will take time eventually
after some hours, if you are not going to repeat the exercise bout in a
short time, you donít really care about it.
KT: Well, but I would argue thatís the same with protein synthesis! I
mean, probably the same thing. I think what we will find is itís gonna
be the same pattern starting with glycogen is that at first studies came
out saying you got to have glycogen the first hour or two, or else, I
mean, carbohydrates are crucial for endurance exercise. But then, they
discovered that, unless you are gonna repeat that exercise very soon,
probably you are gonna build enough just with the normal regular
carbohydrate over the time. I bet you that protein is gonna be the same,
same story. As far as breakdown goes, remember, I have written it in
reviews myself that you have carbohydrates for the insulin response and
when you look at net protein balance, you are talking about the balance
of all proteins, so that insulin does seem to have the effect of not
letting the protein breakdown go as high. But, protein breakdown is a
very complex situation. There are at least four or five different
pathways, and so when we measure protein breakdown, we are measuring all
those at once, the sum total, which would really Ė sort of Ė equate to
the weighted average of all those. And so, some of those I think are
absolutely critical for the adaptive response. For example, the calpain
system seems to be Ė and this is still not in humans necessarily, but at
least in animals Ė seems to be responsible for the initial breakdown of
damaged proteins from the exercise. And then that goes to the ubiquitin
system. And then those peptide chains go to the ubiquitin system for the
rest of the breakdown. So, it looks like probably these two work in
concert to get rid of the proteins than you need to get rid of, so you
can use those amino acids to build anew proteins that are gonna make you
bigger and stronger. So, I think itís much more complex than we
understand, that just a damp in protein breakdown isnít necessarily what
we want to do. So, I really donít have resolved that as far as making a
recommendation goes, I think probably carbs arenít gonna hurt anybody
and that probably people overreact and say, you know ďooh, carbs bad!Ē,
because people 20 years ago said ďooh, fat bad!Ē, and now itís carbs,
so, and before that, protein was bad! I think all of them are necessary,
we evolved as a species to respond to these exercise stimuli and eating,
and we are probably making a little but too much out of it when we try
to get into these nitty-gritty details. And itís certainly too complex
for me to make a recommendation on, at this point. We are trying! But, I
think carbs is probably up to the individual. As long as they get enough
in the 24 hours, so that the glycogen isnít depleted, if they donít want
to have it right after exercise, thatís probably fine.
YK: Isnít it more reasonable, if you had to pick a time during the day
to ingest carbs, as they say ďto avoid them turning into fatĒ, wouldnít
the best time of the day be just around exercise?
KT: Probably! Probably because they are going to be in this situation
where they are trying to replenish their stores, so really youíve
probably got a very good point that carbsÖ
YK: Yeah, itís the pathway whereÖ
KT: Yeah, because their muscle is going to be stimulated to put those
carbs into glycogen at that time. So, you know, you can make a very good
argument that carbs after exercise, for resistance exercisers.
YK: And also before that, right?
KT: Yeah, well just as long as youÖ.you know, I wouldnít necessarily
recommend carbs before a workout for a weightlifter unless they felt
like they werenít able to maintain that workout. So, if they eatÖ
YK: What is the reason for that?
KT: Well, it would be up to them. In my opinion, itís not critical
either way. Itís a personal preference and what works best. If they have
enough glycogen in their muscles to get through their workout the most
effective way they can, then they probably donít need the carbs. Some
people though, their blood glucose really drops with exercise, and so
maybe they need a little bit of a boost. So, I think the athlete needs
to determine what works best for them. And we canítÖone size does not
fit all. And thatís always the problem with making these
recommendations. Everybody wants a one-size fits-all solution. Itís not
YK: OkÖ! Now letís go to cardiovascular exercise. What are the protein
needs for people engaged mostly in cardiovascular or endurance exercise?
People do that usually with a focus on losing fat. Is timing of protein
ingestion important here as well? For example, you have a scenario where
someone is doing a cardio session, and they are doing it on an empty
stomach sometimes, because they think they will be using more fat as
energy during the workout. So, does ingestion of some protein for
example, before this session, in order to minimize muscle damage, would
this be recommendable? Or itís negligible so that no one should care
KT: I donít know, because I donít think the evidence is there. I mean, I
can only speak from what I think is solid scientific evidence, and I can
say without a doubt that the evidence to make a recommendation on either
side of that is not available. Now, there are a lot of studies that have
been done, but most of them are pretty poor, and they base their
evidence on, for example, creatine kinase measurements and stuff like
that, which is crap. So, I definitely donít think that protein intake
before exercise for endurance athletes,... I can honestly say that there
is not evidence available at this time that that is beneficial.
YK: You are talking about the performance, not the fat loss, right?
KT: And for fat loss, thereís certainly none. When they talk fat loss,
what they are basing that on is the respiratory exchange ratio during
the exercise, and/or after. And thatís very limited toÖ.itís sort of a
snapshot of when they measured it. And think about how long theyíve
exercised, even the top athletes are going only to go for 2-3 hours,
maybe 4. That still leaves 20 hours in the day. So, how much fat are
they gonna lose during that time vs the rest of the 20? And how is that
overall going to impact their fat loss? So, I think itís a mistake,
especially for recreational athletes, itís only an hour. And you know
what, the rate of fat burning based on RER during exercise is something
YK: Half a gram.
KT: Yeah. Half a gram. Half a gram per minute.
YK: Per minute, yes.
KT: So, you see, you are talking 30 grams.
YK: Yeah, the rest of the day you will be burningÖ
KT: You have a slice of pizza, itís back, you know?
KT: So, again, itís not as simple as everything.
YK: Yeah, ok.
KT: If someone wants to eat protein, and it doesnít bother them, and
they think itís good, then I probably wouldnít tell them not to, butÖ
YK: You donít see the benefit.
YK: Ok. I want to ask you about a paper of yours. Recently, you (among
others) published a study where postexercise muscle glycogen rate of
synthesis with combined (2:1) glucose:fructose ingestion was the same as
with pure glucose during the first 4 postworkout hours. In this paper,
you showed that during the first 4 postworkout hours, it doesnít matter
if you drink glucose or if you drink 2:1 glucose:fructose. Because some
people say ďdonít drink fructose postworkout because it replenishes only
liver glycogenĒ, etc. So, the first 4 hours, thereís no difference in
muscle glycogen restoration. How about the net muscle protein balance?
Would there be any difference there? Because, fructose is a carbohydrate
with totally different behavior.
KT: Yeah. I have no idea.
YK: You didnít measure that, right?
KT: No, we didnít measure that. That study was designed only to measure
the glycogen. And the idea had to do with the transport of the
carbohydrates across the gut, so that you can get a better transport, so
a better glycogen restoration. But, it didnít work, and itís possible
that, as you suggested, part of that was because fructose ended up
mostly in the liver. We donít know that. But certainly, we didnít even
attempt to measure any protein metabolism parameters. So, I really have
no idea how fructose would influence that.
YK: Alright, next question. Something about the statistical
significance. In certain published papers, we see researchers using
statistics to report certain findings as "non-significant". However,
sometimes what is non-significant in statistical terms, would be very
significant for a recreational athlete and often we see people avoiding
to do/eat/drink something that worked for themselves, because the study
showed non-significant differences. Is it due to small sampling in the
study? I have an example on this. Someone was comparing creatine
monohydrate and creatine ethyl ester. And they measured the amount of
water kept in the body, and they didnít find any difference. But there
are certain people who say ďno, creatine ethyl ester does not keep so
much water on your bodyĒ. And there was this difference in the results,
but the statistical error was large, so they said ďit was
non-significantĒ. Do you have a comment on that?
KT: Yeah I do, absolutely. There is a difference between statistical
significance and physiological significance. There is no question.
Studies are always limited. They are limited by a) the sample size as
you said, sometimes, and thatís a common reason that papers donít get
published is cause they donít have the statistical power, I mean enough
subjects. And, I think, in a lot of ways as scientists and researchers,
because we rely on the statistical significance, we do a disservice in a
lot of ways to athletes. Now, as far as recreational athletes go Ė you
specifically mentioned those Ė I think the difference is much less
important for them. I think the real difference is with the top elite
athletes where a one percent in performance is the difference between a
gold medal and not even making it to the Olympics, or something like
that. And a lot of our measurements, we cannot measure one percent, so
we measure three percent difference and say ďoops, that wasnít
statistically significantĒ and maybe thatís not the best way to look at
it always. So, in practically based in-point type studies, I think that
different types of statistics need to be performed. In metabolic
studies, then I think statistical significance is probably more
relevant. So, there are different ways to look at it. Thereís a guy
named Will Hopkins who has been writing the last few years about this.
Heís developed a different type of statistical analysis to more
practically evaluate these types of things, and weíve started using
those in some of the publications that weíll have coming out soon.
Because I think thatís a very very important point for these
KT: But, when you try to interpret metabolic or molecular type studies,
I think you have to use that. You have to evaluate somehow whether or
not what youíve measured is actually real or is just random chance. And
in statistics, thatís what thatís for. Whether or not we use statistics
appropriately is the question.
YK: So, what is in your opinion the hottest topic in protein research
today? Or, to put it in other words, what is currently the most
interesting unanswered question in protein research?
KT: Wow. I donít know, thereís about a hundred of them!
YK: Is there something youíd be dying to know?
KT: Well, maybe not necessarily one question, but one general theme ofÖI
think we need to really try to evaluate where the amino acids that are
being ingested, are going. So, what type of proteins are being
stimulated with different types of exercise and whether or not the amino
acidÖfor example, if you are an endurance athlete and you exercise and
you take protein afterwards, and you are a weightlifter and you take
protein afterwards, obviously the phenotypic response is different, but
how are you influencing that with the protein ingestion afterwards. Do
the amino acids from the protein go to mitochondrial proteins with
endurance exercise and myofibril proteinsÖ
YK: Canít you do that with isotopic techniques?
KT: Yes, we are doing that now. We are trying to. We are still in the
first baby steps of that. And that paper I showed you, Dan Moreís paper,
that was probably the first one to really start looking at that. But
that was only one type of exercise.
KT: So, I think that something along those lines is really what we have
to start focusing on, cause thatís whatís gonna allow us to make better
recommendations without doing these in-point studies. We can do an acute
study to see some aspects, and then we can try to evaluate that better
with the influence study.
YK: Dr. Tipton, thank you very much, this was a very interesting
interview. I have a final question, how much protein do you ingest per
KT: (laughs) Iíve no idea. I never measure. Again, I am not in that
elite where one percent makes a difference, so, as long as I get enough,
I am happy.
YK: Thank you very much.
KT. Alright, you are welcome, my pleasure.