Dr. John Ivy has served as Department Chair of Kinesiology & Health Education for the past 13 years at The University of Texas, where he has been a professor since 1982. As an exercise physiologist, he has spent time running UT’s Exercise Physiology, Metabolism, and Research lab, studying the acute and chronic effects of exercise on muscle metabolism, with special emphasis on carbohydrate regulation and nutrient timing. A world-renowned expert on the role of nutrition and exercise performance, he has published over 160 research papers and review articles, co-authored and published three books, and led research initiatives for EAS, Accelerade, PureSport, Wheaties and other major consumer brands.
ATLX sat down with Dr. Ivy for an hour to discuss nutrient timing and its importance in the training of elite athletes.
Dr Ivy, you are an expert in the field of nutrition, exercise and performance. How important is nutritional understanding for elite athletes?
Dr. Ivy: Well, I’ve been working in the area of nutrition for all of my research life and studying its relationship to exercise and performance. I don’t think one can overstate the importance of nutrition for the elite athlete. An analogy would be that you can fine-tune an expensive racecar, but if you put low-octane fuel in it, it’s not going to perform very well. An elite athlete is a lot like that. They can train very hard, but unless they’re eating properly and taking in the right nutrients at the right time, the training isn’t going to be as effective. They’re not going to reach their potential as an athlete without having the proper nutrition plan.
And does this go for the everyday athlete? Is it just as important?
Dr. Ivy: Well, you know the everyday athlete does not have to perform for a livelihood like the elite athlete, so I think it’s actually more important for the elite athlete to fine-tune their nutrition. But for the everyday athlete, it’s still very important. They’re not going to train their best or adapt to the training as well if they don’t consider their diet and their nutritional supplementation.
Can you provide a specific example of how one who follows these guidelines might differ from one who does not follow a nutritional program or regime?
Dr. Ivy: Sure. There are a number of examples showing that proper nutrition and supplementing at appropriate times improves performance and improves the training of that person. We can look at two times that you might want to supplement. One would be during competition. We know that appropriate supplementation during an aerobic competition, such as the Tour de France or a marathon, can improve performance by up to 15 percent. So if you can supplement during that time, proper nutrition can be a real advantage.
Post-exercise supplementation is also extremely important for the elite athlete and for average individuals. We’ve shown, for example, that you can take a group of untrained individuals and train them for four to five weeks. Half the group supplements with appropriate nutrients immediately post-exercise while the other half gets the supplement two hours later. They’re getting the same exact supplement at different times.
Those who get the supplement immediately after exercise will see a two-times-faster increase in their maximal oxygen consumption, a greater loss of body fat, and a greater increase in muscle mass than the group that supplemented two hours later. So just that two hours window makes a tremendous difference in the adaptive response of the athlete. There are studies showing that athletes who do strength training and supplement around the workout will gain muscle mass and strength twice as fast.
This has real implications for the average person, particularly older individuals. When we get older, after the age of 50, we lose about 1 to 1-1/2 percent of our muscle mass every year. After a while, this can be detrimental, leading to frailty and reduced mobility, greater instance of falls, and so forth. This condition is called Sarcopenia, or loss of muscle. We know that as individuals get older, it’s harder for protein synthesis to occur and for muscle to be generated.
In one study, researchers took 75-year-old individuals and had them do weight training or resistance-exercise training. They gave one group a carbohydrate/protein supplement immediately after exercise and another group the supplement two hours later. The individuals who got the supplement immediately after exercise showed an increase in muscle mass and strength. The older individuals who got the supplement two hours later showed no increase in muscle mass, with only slight increases in muscle strength, which is probably more neurological than anything. So, even in older individuals in which there is an inability to generate new muscle by appropriate nutrition, you can actually cause new muscle to be developed.
That’s incredible. You are also the author of two books (with Dr. Portman) and helped create a sports drink product, PureSport. Let’s start with the books. You wrote Nutrient Timing: The Future of Sports Nutrition (Basic Health Publications), in 2004. Can you explain the premise of that book?
Dr. Ivy: Sure. Nutrient Timing is based around the premise that eating at the appropriate times will increase the efficiency by which the body will use the nutrients consumed to improve performance, to build and repair tissue, and increase training adaptation. These responses are actually hardwired into our DNA. In other words, this is something that our bodies developed hundreds of thousands of years ago; how to respond to exercise and how the body alters its ability to use nutrients based on our physical activity pattern.
And what about the research for Nutrient Timing?
Dr. Ivy: I actually started looking at this a number of years ago in my dissertation research back in the 70s. I was interested in how the muscle recovered its fuel stores after exercise. In doing this research, I noted that the muscle was much more capable of taking up carbohydrates after exercise than it was at any other time. This made a lot of sense because during exercise, you reduce the muscle’s carbohydrate stores or glycogen stores. This muscle glycogen is essential for certain types of exercise, particularly high-intensity exercise.
So if you think about it as a hunter-gatherer situation, the hunter-gatherer is out there stalking and trying to kill his prey for food – this is an energy-requiring process. It may take a lot of energy and a lot of work to do that, so there’s a depletion of muscle glycogen or fuel stores in the muscles. If it takes a long time to regenerate this fuel, it makes the human vulnerable, so he becomes the prey. The body has adapted this ability, after a hard exercise, to respond to nutrient intervention much more effectively. And it’s not only just to increase fuel stores within the muscle, but also to generate protein synthesis and training adaptation.
We just didn’t call it nutrient timing back then. It just came together after a while. Some research came out from other individuals and then, just putting the pieces together, we came up with this theory on nutrient timing. Since the book came out there have been hundreds of studies on this topic, looking at the mechanisms by which it functions.
A lot of people don’t understand this. I’ve noticed that some people, after a cardio workout, actually believe they shouldn’t eat because they’re just going to retain the calories that they consume. They really don’t understand the importance of rebuilding the muscles and recovery.
Dr. Ivy: That’s probably the worst thing that they could do. Our work has shown that while most people are concentrating on weight loss, what they should be looking at is body composition. So it’s not that they want to lose a lot of weight; what they want to lose is fat, but they also want to retain or increase their muscle mass.
So what we know is that when individuals work out, one of the best things they can do is actually consume the appropriate calories immediately after exercise. What this will do is enhance recovery, reduce muscle soreness and allow individuals to work out more consistently day after day. From the standpoint of body composition, it reduces fat more effectively while maintaining muscle mass.
When individuals don’t eat after exercise, they lose out, and they’re going to eventually consume the calories anyway. And those calories are much less effective in burning fat or causing protein synthesis and training adaptation and refueling the muscle, which are energy-requiring processes that require fat burning. They lose out on that. They lose out on the additional fat burning that’s gained by consuming a carbohydrate/ protein supplement post-exercise.
Post-exercise, the body accelerates our carbohydrate fuel stores and protein synthesis (which is for tissue repair and increased muscle mass or other tissue development); those are energy-requiring processes. So if I take in a carbohydrate/protein supplement immediately post-exercise, the carbohydrate is going to be stored as glycogen in muscle; the protein is going to be broken down into amino acids and used to generate new protein in muscle. These metabolic processes are energy-requiring. The body isn’t going to use these fuels for energy. What its going to use is fat. So when you supplement appropriately post exercise, you actually increase fat burning while enhancing the recovery process.
Okay, great. Let’s touch on your other book with Dr. Portman, Hardwired for Fitness (Basic Health Publications, 2011). Can you give us a quick overview?
Dr. Ivy: Sure. Hardwired for Fitness is really an extension of Nutrient Timing. Our bodies are hard-wired to be fit. In other words, it’s natural for us to be fit. We have this genetic predisposition to be physically fit, and our bodies have functional circuits hard-wired into our DNA that control our weight, our body composition, and our capacity to be active, to be fit.
To achieve the body composition and fitness level we desire, our circuits have to work in harmony. To get these circuits working together, we need a critical level of physical activity per day, we have to eat appropriately, and we have to get sufficient sleep. Unfortunately, with our modern lifestyle, it becomes difficult to do this. So we have to consider working physical activity into our daily routine.
When I say physical activity, I’m not referring necessarily to exercise. This can be non-exercise physical activity, but you have to burn a certain amount of calories per day, whether it’s through regular exercise or through general physical activity such as getting up and walking to the water cooler, taking the stairs up to the office, or walking from the car to the store. We need a certain physical activity pattern. We need a certain eating pattern, and we need a certain amount of sleep to get the circuits in harmony. Once these circuits are in harmony, controlling body weight and fitness levels is actually very easy. It’s that simple.
Okay, and what about the research that led to Hardwired for Fitness?
Dr. Ivy: Well, the research for that book actually came from a number of different disciplines – from research on metabolic regulation, biochemistry, exercise physiology, weight control studies, nutrition studies, circadian rhythm studies, analysis of sports performance, etc. We know that the body has four basic circuits: there’s an energy circuit, stress circuit, appetite circuit, and a protein turnover circuit. And these circuits are in an ebb-and-tide type of activity over a 24-hour period. So they should have a certain pattern, but unfortunately our lifestyle gets in the way, and this is why we become overweight or our cardiovascular fitness drops.
So the circuits work in harmony, they work together. If you overwork one circuit, it’s going to affect the other circuits. For example, if I’m very sedentary and don’t get sufficient physical activity during the day, my appetite circuit overworks, and I overeat relative to the number of calories I burned. Research from the 40s and 50s shows that there is a critical threshold of physical activity for control of appetite, so as physical activity at this critical level goes up, appetite goes up, and that caloric expenditure equals caloric intake.
But it also showed that as physical activity declines or caloric expenditure declines, caloric consumption goes up, so the more sedentary you are, the more you tend to overeat. The appetite circuit is controlled by our physical activity level during the day. Our physical activity level controls our stress levels, and, if we are overstressed, we tend to gain weight because of elevations of cortisol in our blood.
So Hardwired for Fitness deals with these circuits and how you control them in a reasonable way. Just slight changes in lifestyle can make a significant difference in how one controls their body weight and percent body fat. It’s really about doing things naturally during the day and getting these circuits back in harmony so that your body gets into the physical condition you want it to be in without stressing out about having to work out a couple of hours a day, working really hard, and so forth. You have to take a holistic approach to it.
It really makes a lot of sense. If you don’t get some physical activity, it will make you hungrier. Some people have a problem with what they call bored eating. They eat while they aren’t doing anything, because they aren’t doing anything.
Dr. Ivy: If you look at the research on dieting, individuals who diet are much more susceptible to being overweight than those who have never dieted before. Research has shown that people who diet, may lose weight for a little while, but eventually they’ll gain the weight back. But not only that, they’ll often gain more weight later.
Another aspect, which most people don’t understand, is that when people diet, and that’s the only way they try to lose weight, they lose a lot of muscle mass as well as fat. Then when they gain the weight back, they don’t replace the muscle mass. They gain the weight back in fat, so what they’re actually doing over time is lowering their lean-body mass, and the percentage of body fat is increasing.
There is a lot that people don’t understand as to what happens while dieting, when you try to lose weight just by dieting without incorporating physical activity in the plan. And when you eat can have a direct effect. One of the things we pointed out in Hardwired for Fitness is what we call functional eating. There are certain times of the day when you should be eating and certain times of the day when you shouldn’t be eating. What you eat and how many calories you consume during certain times of the day can make a dramatic difference in weight gain and body composition.
And there was a really good study done, maybe out of Johns Hopkins, where they took individuals and put them on a caloric-restricted diet. They had another group on a low-carbohydrate diet where they were given, I think, 1100 calories of a low-carbohydrate diet, and a small breakfast. The other group had a 1200-calorie diet, but it was a high-carbohydrate diet with a large breakfast. The individuals who had the small breakfast consumed the majority of their calories later in the day and at night, while the individuals who had the large breakfast had a small amount of calories later in the day and at night.
You would think that the individuals that were on the high-carbohydrate diet would not lose as much weight. But what they found was that after, I think it was eight weeks, the individuals on the low-carbohydrate diet, with the majority of their calories coming in the afternoon and at night, lost ten pounds, whereas the individuals who had the large breakfast and the high-carbohydrate diet lost 37 pounds on average. Just the timing of when they consumed the calories made the biggest difference.
I was just about to ask you if it’s true that consuming more calories in the morning is the better approach.
Dr. Ivy: Oh, yes. There are all kinds of studies that show individuals who eat a solid breakfast are much more likely to control their body weight than those who skip breakfast. There are a number of reasons for this. One of the major reasons has to do with the stress cycle that we talked about. Early in the morning, the stress hormone cortisol is elevated because we tend to have low blood sugar during that time, and cortisol is released to break down protein in the body and release amino acids that can then go to the liver and be produced into glucose.
If you don’t eat in the morning to replace the carbohydrate that’s used overnight, cortisol remains elevated until you do eat. And cortisol increases fat storage in the abdominal area. So individuals who don’t get up and eat a solid breakfast in the morning are exposing themselves to this high stress level of cortisol for long periods of time until they do eat, therefore accelerating fat production.
Let’s move on to discuss some of your work with General Mills, Coca-Cola, Pacific Health Labs, and others. Can you share some of your work with these major consumer brands?
Dr. Ivy: Well, you know I worked with a number of companies to develop different products. With General Mills, we put together what’s called Wheaties FUEL, which was produced as a high-density cereal for athletes who work out in the mornings. They can eat a small bowl of this cereal and get a large amount of calories without feeling overly full. It provides the necessary nutrients to lower the blood cortisol level, get blood glucose back up and also fuel their physical activity and workouts without a full feeling in the stomach. And it’s also very good for snacks and post-exercise supplementation. We also developed a high-protein fuel bar for post‑exercise workout recovery.
I worked with Pacific Health Labs for the development of Accelerade, which was the first carbohydrate protein sports drink on the market. Also helped to develop Endurox R4, which was one of the first carbohydrate/protein recovery drinks on the market.
And then I developed the vitamins that are sold in Lifetime Fitness gyms around the country. I also developed two sports drinks for Human Performance Labs: Pure Sport Workout and Pure Sport Recovery.
There are other companies that I helped in developing some other sports drinks and nutritional products, different bars, and so forth. It’s been something I’ve done for a number of years. I’ve also consulted with a number of companies on nutritional products. And I’m chairman of the advisory board for EAS, which is a subsidiary of Abbott Laboratories, the nutritional arm of Abbott Laboratories.
Going back to your work on nutrient timing, did you work with elite-level athletes in your research?
Dr. Ivy: All of the research I did originally was actually done as animal research, on rats.
Dr. Ivy: Elite rats, right! But looking at mechanisms, it’s a lot easier initially to start off with animal models so you get some idea of what to be looking for when you do human work. In doing human work, we had to do muscle biopsies, and you want to know what you’re going to be looking at and make sure that you’re looking at the right thing before you start that type of work. But elite athletes are very difficult to get for study subjects. Now in the case studies, that’s different. We’ve obviously advised the athletes to do certain things. They were seeing improvements in performance, but it was all really based on what we learned from highly trained athletes or from novices.
We’ve worked with really good athletes in the Austin area, particularly because there are a number of excellent triathletes, marathoners, cyclists, and so forth that we can pull from. They may not be elite athletes, but they are really good athletes, and they’re capable of doing extremely well on lab tests as far as exercise performance is concerned. And we can study them extensively. They don’t mind getting muscle biopsies and things like that. So most of the work that we’ve done really has been with highly trained athletes.
Could you tell me about the results you saw from working with those athletes?
Dr. Ivy: Well, the results depended on the study we were doing. In Nutrient Timing, we have several phases. We have the energy phase, the anabolic phase, and the growth phase. In the energy phase, which is during exercise itself, we looked at the utilization of energy for purposes of performance or exercise. The anabolic phase is the initial recovery phase after exercise, and there’s a certain metabolic window or anabolic window there, when the body is really responsive to nutrient intervention. And then you have the growth phase, which is a natural phase that occurs during the late part of the night and early morning hours. But this is affected by what you do during the anabolic phase. So if you can respond appropriately in the anabolic phase, this has an effect on what happens during the growth phase. A lot of research has shown that if we supplement during exercise appropriately, we can improve performance dramatically. Depending on the type of exercise, we can also reduce muscle damage, and we can affect the recovery process to some extent.
The anabolic phase, and I think this is the most critical phase of nutrient timing, begins immediately post-exercise. So while exercising, we know that we’re going into a state where there are hormonal changes and metabolic changes in the muscle. This allows fuel to get to the muscle to support the exercise, and this is sort of a catabolic state. Certain hormones that break down fuel stores and break down tissue are released, and that allows for fuel to get to the muscle.
When we stop exercising, this catabolic state doesn’t change unless we change it because the muscle is depleted of its fuel stores. The body continues to stay in this catabolic state, or tissue-breakdown state, until we do something about it. That’s what’s so bad about not supplementing immediately post-exercise; you stay in this catabolic state for a long period of time, and that can bring about a lot of muscle damage and tissue breakdown, and you’re not recovering very well. What we know is that immediately after exercise, we can reverse that catabolic state very quickly by taking in the appropriate nutrients. If you take in the appropriate nutrients, then you get the added benefit of maximizing the change that we want.
The body has geared itself up for rapid recovery. When you take in a carbohydrate/protein supplement immediately after exercise, or within the first 30 minutes after exercise, you’re going to see the tissue able to soak up these nutrients and use them appropriately for refueling and tissue repair, and for protein synthesis.
This last part is extremely important because protein synthesis is training adaptation. What do we mean by that? Well, when an athlete is training, he or she is trying to train to improve. That improvement may be an increase in muscle strength, it may be an increase in muscle endurance, it may be an increase in cardiovascular endurance. But all of that improvement is dependent on protein synthesis. If you think about it, if one wants to get stronger, he or she wants to build more muscle mass, which requires protein synthesis. If an endurance athlete wants to increase endurance, he has to increase the mitochondria in the muscle. That’s protein synthesis.
So the faster we can turn on protein synthesis, and the magnitude at which we can turn it on, will dictate how fast we adapt to the training response of the exercise. The exercise training response doesn’t occur during the exercise, it occurs during the recovery process. And you can affect that dramatically by the nutrients you eat and when you eat them. Now this anabolic window or metabolic window only lasts for a short period of time. So, if you don’t take in the appropriate nutrients post-exercise, then your body will not respond maximally until after the next exercise, and you lose the chance of recovering rapidly and bringing about a faster training adaptation.
We’ve also shown that if you get a rapid increase in recovery immediately post-exercise, this allows for a greater growth phase or a greater protein synthesis and training adaptation that occurs during the growth phase as well. Our research has shown that individuals who are supplemented immediately post-exercise increase their training adaptation much more rapidly than individuals who ignore supplementing immediately post-exercise.
If I understand this correctly, the energy phase is when you are physically active during your exercise or workout. The anabolic phase is a short period of time, maybe 30 minutes or so after a workout, when you want to consume the protein/carbohydrate mix and supplement. And then the growth phase is an extended period after the anabolic phase where muscle recovery is using the nutrients that are consumed during the anabolic phase? Is that correct?
Dr. Ivy: Yes, sort of. The thing about the anabolic phase is that once you turn it on, you can keep it going by supplementing periodically. So someone who works out really hard and then immediately takes in a carbohydrate/protein supplement, (it doesn’t have to be a drink, you could have a peanut butter and jelly sandwich and add some protein to it), can keep it going by supplementing again about every two hours.
What we suggest athletes do is start the process with a supplement immediately after exercise and then, about two hours after, plan to get one of their meals. It could be that they worked out hard after breakfast, got a supplement after the workout, and two hours later they’re eating lunch. Or they work out really hard at 4:00 pm, get a supplement, then at 6:00 or 6:30 pm, they’re getting supper. You can do this in two-hour blocks. Once you get that going rapidly, then what happens is that during the growth phase, which is at night, this process will be maintained to a greater level than it would be if you hadn’t started the process at this rapid pace immediately post-exercise.
Training adaptation can continue on through the growth phase. And there are things that you can do to assure this will occur. For example, an hour or so before you go to bed, have a high protein snack of about 100 calories. This will help continue the training adaptation during that growth phase.
Would an elite athlete’s body respond differently throughout these phases than say just an average, everyday athlete?
Dr. Ivy: Yes, that’s a good question. It’s going to depend on what part of the adaptation you’re looking at. With elite athletes, let’s say an endurance athlete, a marathoner, we know that athlete will be able to recover their fuel stores and repair their tissue faster than average athletes. But the average athlete will be able to adapt faster than the elite athlete from the standpoint of training adaptation, meaning increase in maximum oxygen consumption or muscle endurance.
The reason is that the elite athlete is so close to their maximal genetic potential that it becomes harder and harder to improve in their performance and improve in their training adaptation, whereas the average athlete, or even the highly trained athlete, still has a ways to go. It’s like a learning curve. The further away you are from your genetic potential for fitness, the faster the training adaptation occurs. But over time, it’ll start to slow down and become harder to maximize your potential.
You won’t be able to do it unless you have the appropriate nutrient program to do it. So you can train all you want. In fact, a lot of people train really hard, and they’re wasting their time because their diets and nutrient supplementation are not geared to maximizing their potential. The bottom line is, from an acute standpoint, the elite athlete adapts much faster and recovers much faster than a regular athlete, but the regular athlete, from a chronic training adaptation, will gain more because they have more ground to gain.
As far as nutrient timing goes, do you have any guidelines or general recommendations for everyday athletes that stem directly from your research?
Dr. Ivy: One thing that comes to mind is “routine.” They need a routine that allows for eating at the appropriate times, developing a nutrient plan around functional eating and appropriate nutritional supplementation post-exercise, and getting sufficient sleep as well as getting their workouts in. Getting their workouts in is one thing, but you really need to develop a good nutrient program that is based around what we call functional eating – eating the appropriate nutrients and calories at the right time during the day, supplementing appropriately post-exercise and during the workouts, and making sure you get sufficient sleep.
It has to be a routine. You have to get into this routine and it will dramatically improve the average athlete’s performance and training adaptation.
Make and plan and prescribe it.
Dr. Ivy: Right, exactly. Make and plan and prescribe it.
Anything you would like to add?
Dr. Ivy: No, I don’t think so. If people want to know more about this, they can consult our book, Nutrient Timing. I think for the average person that wants to control their body weight, wants to have good general fitness, they really should read Hardwired for Fitness. It’s a simple program that anybody can do because you’re just incorporating into your daily life small changes that will make dramatic differences. It’s just doing small things during the day that can make a big difference – getting a good breakfast, eating solid meals, supplementing after your workout, and just getting into the habit of a physical pattern during the day that’s going to help you burn more calories. Just park your car as far away from the mall door and taking that walk.
Take the stairs.
Dr. Ivy: Yeah, I walk up the stairs every day to my office, which is on the 8th floor. People look at me like I’m crazy. But, you know, it’s just doing those types of things that can make a difference.
I just want to mention, quickly, one other study that’s really important, and it has to do with a protein in the blood. It’s called hormone-sensitive lipase or lipoprotein lipase. Lipoprotein lipase is produced in the capillaries and it breaks down triglycerides, which are stored in fat. Now if there’s a lot of lipoprotein lipase active, the triglycerides are broken down and taken up to the muscle and heart as fuel.
Now what happens is when we sit for four or five hours without moving, our lipoprotein lipase goes away, so our muscle’s ability to remove that fat in the blood is dramatically reduced. All we have to do is get up every few hours and walk for about five minutes and we regenerate that lipoprotein lipase and more effectively burn fat during the day. It’s just getting up and walking to the water cooler, going to talk to somebody, things like that will make all the difference in the world.
Most people aren’t aware of any of this.
Dr. Ivy: Exactly. I think The ATLX Channel is really going to help with educating the people to the point of where they can understand and plan a lot of this stuff. If we had more information out there about how good it is just to get up and walk for five minutes every hour, how we can increase our physical activity patterns during the day, the adverse effects of just dieting without incorporating physical activity into the program, information like that would make a dramatic difference. That’s one of the real problems when people pick up books that have a science base to them. They turn them off because they haven’t heard a lot of these terms before.
They get overwhelmed by it.
Dr. Ivy: Right. They get overwhelmed. They don’t live in that space. It’s too hard, it’s too complicated. So I think maybe breaking it up into these little discrete pieces of video or information will hopefully, over time, help people have a broader, collective understanding of what they’re trying to achieve whether it’s weight loss or whether it’s fitness – just kind of demystify it all.
ATLX Expert: Dr. John Ivy
Wheaties Champions: Dr. John Ivy
The University of Texas Faculty Profile
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