Jesse Kropelnicki just had an article on Xtri about so called ‘Starvation workouts’, or workouts where you try and force your body to function with higher aerobic efficiency by not feeding it what it would most like to have (pure sugar) and thus the hope is that you would be training it to default into slightly more favorable substrate usage ratios the next time you workout. In short, teach your body to burn more fat as fuel source so it uses less of the more limited carbohydrate fuel source at any given intensity.
Here’s a copy of the article. I have no idea if it is copyrighted or whatever, I presume he writes it and distributes it for free so that it gets read and he gets the publicity. I’m posting it here… so it gets read… and I can vouch for the guy otherwise having a lot of very good and very interesting stuff to say (The stuff written about critical volume has played a foundational role in how I think about training). You can read his stuff on the QT2 website as well as occasionally on XTri… so there’s my publicity plug…
The main focus of Ironman training and racing is on the improvement of metabolic efficiency. Developing metabolic efficiency is nothing more than training the body to use aerobic energy systems at the highest paces/wattages possible. This is the least costly way to fuel the body during exercise. There is a great deal of debate around how best to develop this aerobic efficiency. I, as most, would argue that training at intensities right around aerobic threshold (AeT) is the most effective way to improve the body’s aerobic efficiency. But, a recent push makes the argument that dietary changes can impact these adaptations. To this end, it has been hypothesized that “starvation workouts” can help to promote efficiency. These are rides and/or runs where athletes essentially starve themselves, in an effort to force the body to use fat as its fuel source. For example, an athlete on a long aerobic ride of 3 to 4 hours would consume only water, throughout. In my opinion the research on this practice is very uncertain, and is accompanied by a great deal of potential detriments, none of which make it an acceptable risk. Some of these potential detriments include:
1) Starvation workouts can be extremely catabolic, as the body is forced to attack lean muscle mass in order to create carbohydrates for fuel. This process of neoglucogenesis is nightmarish for lower BMI athletes, who are already strength limited, and older athletes (females beyond the age of 45 and males older than 50), who by the nature of their age have difficulty maintaining lean muscle mass. This assault on the body disintegrates muscle mass, thus exacerbating an already problematic limiter. Furthermore, depriving the body of the fuel that it needs to train over long durations can set the stage for a compromised immune system, leading to missed training time due to illness.
2) I am a firm believer that athletes should avoid nutritionally limited workouts, at all costs. In essence, never ever bonk! Be it a typical training workout or race day, it should NEVER happen. Starvation workouts create an atmosphere primed for bonking. This means that your workout is likely to be limited by a lack of fuel, prior to the physical energy systems being appropriately trained or stressed. This is in direct conflict with the reason why we do all of this training, in the first place, and focus so much time and effort on effective recovery. The goal of any workout should be to promote an environment where the athlete can have better and better workouts, pushing previous limiters, thus increasing fitness. Too many sacrifices are made, on a day-to-day basis, aimed at improving our fitness and racing, to allow our efforts to be limited by that over which we have 100% control over.
3)At the Ironman distance, training the gut to be able to absorb the nutrients in their intended race fuel is part and parcel to effectively executing their race plan. This is especially so for those with high sweat rates. These athletes often experience races that are limited by nutrition, rather than a true display of their fitness. Starvation workouts do not provide the opportunity to train this very limiter….race nutrition! We end up seeing athletes who are forced to walk through a great deal of the marathon, because they have not trained their bodies to consume and process the calories that will be required to race effectively. Because each of our athletes is equipped with a personalized race fueling strategy, that is practiced every single day in training (I cannot begin to tell you how many Power Bars and Power Gels QT2ers consume throughout the year), QT2 continues to produce some of the fastest Ironman marathoners in the professional and age group ranks.
4) I often hear of athletes using these starvation workouts during the early season base phase of training, while simultaneously in the gym trying to build strength. The catabolic nature of these types of workouts mixes terribly with the anabolic atmosphere that should be created, through a well-developed weight-training program, to create a positive hormonal balance.
Ironman racing has a nice clean series of events, namely the swim, bike, and run, with overtones of race fueling throughout and within each. How well an athlete has fueled their race does not typically become apparent until the run. I have always believed that the best way to approach limiters, in triathlon, is to first deal with those that exist in series with one another. With this in mind, and knowing that an athlete’s inability to handle their race nutrition is what typically undermines their Ironman, I try to first focus on this limiter as it typically occurs earliest in the chain of events. It really does not do much good to focus on a limiter that occurs further down the line, since it may never have the opportunity to actually become a limiter on race day. An athlete’s metabolic efficiency, on the other hand, is typically a limiter that appears in parallel with most of his or her other limiters. The cases are rare that an athlete’s race will come to a screeching halt, due to poor metabolic efficiency. Therefore, not until we are 100% certain that an athlete does not have a nutritional limiter, should we begin to even consider any unorthodox ways of improving metabolic efficiency, that could even possibly undermine the athlete’s ability to consume and process appropriate race fuels.
But, if you absolutely insist upon incorporating starvation workouts into your training regimen, I recommend trying it no more than once a month, and not until you have full confidence in all aspects of your training, racing, and fueling. At this time, there simply has not been enough research performed, on the topic, for me to feel confident endorsing it to any of our athletes. As with anything else in life, whether or not to utilize starvation workouts is really a matter of risk versus reward. In my opinion, the possible benefits of these workouts simply do not outweigh the potential risks.
Jesse Kropelnicki is an elite/pro level triathlon coach who founded QT2 Systems, LLC; a leading provider of personal triathlon and run coaching, as well as TheCoreDiet.com a leading provider of sports nutrition. He is the triathlon coach of professional athletes Caitlin Snow, Dede Griesbauer, Ethan Brown, and Tim Snow among others; and nutrition/cardio advisor for professional UFC fighter Kenny Florian. His interests lie in coaching professional triathletes using quantitative training and nutrition protocols. You can track his other coaching comments/ideas via his blog at www.kropelnicki.com.
Jesse is definitely right, there’s not a whole ton of good scientific evidence that this strategy is net-beneficial. That said, it is something Steven Lord had me do during training in 2010. I tried to read up on it, and came to the same conclusion as Jesse, there’s not a whole ton of scientific PROOF that this is a great idea but intuitively it seems like one of the only ways to make the kinds of changes that you’d like to make in your body’s metabolic defaults. Lots of different exercise physiologists will tell you that you get an advantage at ironman by being a fat burner, but there aren’t a ton of people who will tell you how to do it. Alan Couzens profiled the technique he employed with one of his athletes a while ago in some of his writing. Now that I want to post a link to it I can’t find the exact article I’m thinking of. In any case, he had this guy modify his substrate consumption to increase fat, decrease carbs, and do a lot of work at aerobic threshold with a whole heck-ton of patience. I wish I could find the article, what he had the guy doing was low intensity stuff and not the kind of stuff that’s going to make you fast very quickly. It was however, going to make this kid fast in the long run because there were significant gains made to this athlete’s fat usage during exercise. The numbers were mind-blowing actually, this average guy was scoring somewhere near the 10calories/min from fat that people have calculated Mark Allen was able to do during his heydey in Kona (I presume that lots of the guys in the top 10 this year must be around that magic number as well).
I decided to listen to my coach.
Annette said that she was really proud of me a couple times this past year for listening to what he said. Her opinion was that lots of the other people she knew who had coaches often tried to be too smart and didn’t listen, and thus didn’t get the benefit of the protocol as it was designed. I can’t say I listened to Steven all year long about everything, and I did some complaining (thinly disguised as asking tough and frustrating questions) about some things. This was one of the things I think I complained about, but I did do what he was suggesting I do about modifying substrate usage.
This year I had already decided I was going to eat more fat than last when I had been on this idea of making my body into a carbohydrate furnace, ready to pour them in, rev a high HR, and make more watts at any cost. I wasn’t racing so long (less than 5 hours) that I felt there was a huge detriment to doing that. I knew that I could eat and digest at pretty high intensities so my game plan was to just pour fuel on the fire and not worry about running out. This worked, it wasn’t a really long term strategy I found, and I think the lack of fat in my diet was probably a bit unhealthy in other regards. My skin didn’t heal very quickly amongst a few other things that I noticed (along with some search-engine help) were probably an indication that this “burn as much fuel as you can and you’ll go faster” was probably a bit shortsighted. It made me fast at a cost that I identified as being probably not the best for myself. So, that wasn’t a change posed by Steven, but he did put a few other interesting ideas on the table.
Starting early on Steven began suggesting on my endurance focused rides that I cut the carbohydrates completely in the morning before the ride. Now it’s totally possible to load up and feel full without hardly any carbohydrates and I always did that, I never did pure starvation in the manner alluded to by Jesse’s article, however I was doing a form of starvation training. A typical breakfast would be between four and six fried eggs with cheese melted on top. A red pepper, a glass of milk, and a handful of cashews or pecans. I also pre-ran prior to some of those weekend bike rides during the spring to rack up a bonus 40 minutes. Those mornings I’d just eat some nuts or halva with water or milk before the short run, and then come home and make my big pre-ride omelette. Then I’d start riding and I definitely and noticeable wouldn’t have any blood sugar.
These long rides were not completed without eventually getting myself into the carbohydrates and eating sports nutrition (i.e. practicing the race plan) along the way. Generally I’d ride the first two hours on just water and perhaps a bit of sausage or some almonds. That was it though, I’d generally feel pretty slow (even though I wasn’t necessarily being slow) and was just a bit mentally dreary. Considering the fact that your brain won’t fuel itself off anything other than sugar the mentally dragging your ass along the road feeling was going to be par for the course. Then I’d eventually pick up the fuel, and finish off the ride allowing the body to run off of both ingested carbohydrate fuel and processed fat.
Did I observe the four points that Jesse makes? Yes. Did I suffer the consequences he outlines? Only once did I actually bonk and had to pay the consequences of taking this method to to far an extreme by missing out on planned training.
1 & 4 I no doubt experienced the catabolic effect of this kind of training as it prevented strength gains during this period of time. Whether or not it was the low-carb riding that did it or the incessant running I was doing while shooting for 7 runs per week frequency is an open question but I no doubt would say that I didn’t get any stronger during this period of training (Mid-April through Mid-July). I basically made zero gains in the gym with weights between early May and the end of July when I quit strength training. I wasn’t in a period of trying to build strength in the gym, but I would have expected that my leg strength would have improved by the amount of riding I was doing and I’d be able to see evidence of that in the gym. This was not the case, leg-holds on the leg-press sled probably got relatively more difficult as the summer went on even though I did the same set at 270lbs with each leg all the way through. Did I suffer a compromised immune system? No. I didn’t get sick at all, but I can’t rule out that the hormonal effects tied to getting so tired weren’t related to the hormonal effects brought on by operating occasionally with a blood sugar deficit. The worst blood sugar low did result once in a total bonk and came a week before a race which I proceeded to do fantastic at. In a round-about way this could have been something setting me up to get knocked into serious fatigue as a result of that race. I was at a low mentally with motivation and with energy levels the next two weeks.
2 The warning is that if you do this to your body you’re unable to push your physical limiters. OK, if we narrowly define fitness there’s a way to make this statement true. I likely didn’t make any gains with my functional threshold power over 2009 during this season, heaven forbid perhaps it got a bit worse. This is a problem with deciding that your functional threshold power is the best metric for measuring success. As a result of this training I was able to post an age-group fastest bike split and on the run, run within a couple percent of my open marathon time. These are measurements of fitness success both un-acheivable last season, and so I think it’s misleading to say that because you might not be gaining a certain type of fitness by doing these workouts that it means you’re not getting better. If it makes you faster for your target race then that’s the measure of success.
3A true starvation workout doesn’t allow you to practice ironman fueling but I’d suggest that the method I used which is what I guess I’d call hybrid-carbohydrate-starvation is actually an extremely ironman specific way to practice doing the fueling. Starting with a morning-prior-to-the-ride-carboload is going to lull you into a false sense of having your glycogen stores and blood sugar at a maximum before beginning the ride. It will reinforce the idea that your nutrition is not a fragile calculus because you’ve got the glycogen reserve buffer to work against. The ironman swim is going to use up a large chunk of your glycogen and you’re not going to be eating with the “bank in reserve” during the race, you’re eating with the glycogen bank on it’s way to being empty. This is exactly what happens if you start your morning with no carbs, the blood sugar stays down, and while you’ve got some glycogen in your muscles you don’t have a big stash of liver glycogen because your body has used it over the course of the night to keep chugging along.
So would I recommend it? Early in the season (especially at bike camp in early April) I needed to be consistently eating all the way through the ride to stay topped up. Later in the season, I could still eat (I mean, I ate a LOT at Ironman, so I clearly didn’t de-train this ability) but I didn’t feel the need to constantly be eating as the season progressed. I’ll take the desire to eat carbohydrates as a measure that my body was requiring more carbohydrates, it’s generally smart like that. I also felt a lot better during the pre-carbohydrate portions of those rides as the weeks progressed. They set me up with sufficient cycling base to do the hard-ironman specific intervals that the program required as the race grew closer. I could have done all those earlier season rides fully fueled and I would have shown up with a similar cycling base, I don’t know if it would have been any better, but I wouldn’t have changed my need to be constantly pouring sugar into my mouth. I probably would have trained harder during this base period and perhaps would have come into better fitness sooner but that’s then a measure of planning appropriately and not so much what you eat. I don’t have the financial resources available to do the testing to prove that I made big gains in my metabolic efficiency this past year but I am confident that I did. Sorry, no fancy graphs from me for this post. Just a good idea for early-season pre-ride breakfast:
I’d definitely suggest that Jesse is casting this rather experimental kind of training in too negative a light. There are intelligent ways to do metabolic efficiency training and there are unintelligent ways of doing it. By suggesting that no-food starvation training is terrible without considering the middle-ground of beginning long rides in a carbohydrate depleted state I think he’s suggesting that this is something we’re hopelessly unable to improve. While I’m hesitant to really recommend what I did I do think that it’s definitely got merit. I’m quite open to there being a better way to develop this skill with our bodies than the method I used but I’m pretty confident that it is possible to do a better job of it than doing no job at all which is what Jesse is unfortunately suggesting.
