ŇŽŽÁŪťÍŁ Bodybuilding Forum


Dr. Kevin Tiptonís Interview to Bodybuilders.gr
Kavouri, Greece
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 measurements.

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 measurements.

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.

KT: Yeah.

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.

YK: Alright.

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 and obese.

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 whole time.

YK: Ok.

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.

YK: Ok.

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 hypocaloric.

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 true.

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 about?

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 likeÖ.

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?

YK: (laughs)

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.

KT: No.

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 practical-type studies.

YK: Ok.

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.

YK: Ok.

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 day?

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.