This write up has been in the works for some time. Over the years my views on the subject have been evolving and I am finding many competitors have detailed questions relating to nutritional strategies. While the following are not based on peer reviewed, scientifically controlled studies; the engineering thought and estimates will most likely convey the concepts. Due to individual needs and preferences this is most likely sufficient. Additionally, I must inform you I am not a certified nutritionist. At least all this is food for thought so to speak.
As many of you have or are beginning to realize, fueling your body during a stage race is a huge challenge. During a typical ultra you can follow a simple mantra; eat what you want when you want. You have access to unlimited calories and a wide variety of foods. Besides, most ultras are over in less than 36 hours so you can even just gut your way through it even though there is complete body glycogen depletion (bonk).
Stage Racing on the other hand requires more sophisticated and complicated strategies. This is obviously due to the restriction of available calories, duration of the event and the need to keep yourself going during non-racing periods. The following is an attempt to address this complicated issue and enable the stage racer to hone strategies for an optimized performance.
There are many models available to estimate metabolic caloric requirements. Each of these have their advantages and disadvantages. I have settled on using some sort of base metabolic requirement plus an additional amount for the physical exertion of the stage race. One must also realize that this approach and underlying models will most likely not “fit” everyone and you will need to experiment with this.
For this study, we will assume the following:
- 250 km / 155 miles
- Six Stages
- Seven-day event (six days of total of self-sufficiency, the morning of the first day and the afternoon of the last day do not count)
- 70 kg / 154 lb racer weight – male
While most normal base metabolic rate (BMR) estimates are around 2,000 Kcals/day, for this study I use a value of around 2,400 calories per day due to the extra exertion of camp life. This also conveniently rounds to 100 kcals/hour. It also points out a very important fact. If you did nothing but camp out for six to seven days you would require a minimum of 14,400 – 16,800 kcals, which is the range of the typical 14,000 kcal minimum most races required.
But we are not just camping out are we? We are stage racing! So one needs to add the energy requirements to run, jog or walk 250 km. Fortunately there are a multitude of methods for estimating these values. The most common is the 1 kcal/kg/km for running. Given the assumptions above this would require an additional 17,500 kcals. However, this would result in an overestimation to some extent since we are double counting the BMR requirements while running. This can be somewhat corrected for by estimating the time for racing and the time for resting and combining the two. This is illustrated in the following table.
While there is no adjustment for the level of effort, this approach yields an average caloric requirement of around 28,000. This is double typical minimum requirements and translates to 4,660 kcals/day during self-sufficiency.
An alternate method is the Harris-Benedict approach. This method takes the BMR and multiplies it by a factor that relates to the level of exertion. Using the BMR above (2,400 kcals/day) and applying the “heavy exercise” factor of 1.9 yields 4,560 kcals/day. This is in good agreement with the previous method above.
We can therefore summarize that the total caloric requirement for a stage race is around 28,000 kcals or about 4,600 kcals/day of self-sufficiency.
You can get your calories from two sources. The first and most important is what you eat. For the purposes of this discussion you must look at the calorie to weight ratios. Most stage racers are quite familiar with this but I wish to reiterate some basics here that will be necessary for later on. Again, these are generalities and may not represent your particular approach.
Table 2 highlights typical calories to weigh ratios for various food types.
The second and lesser desirable source is your own body. It is a fact that almost every stage racer will lose weight during the event. No mater if it comes from carbohydrates (glycogen), protein (muscle) or fat it comes from your body and there will be a decrease in performance as these resources are consumed. On average the caloric density of body sources are outlined in Table 3. How you utilize body stores depends upon your metabolism and other factors. It should be noted that glycogen only makes up a tiny portion of body caloric stores (typically only 2,000 kcals). Fat stores are typically over 100,000 kcals.
As you can most plainly see you will be operating in a caloric deficient mode during a stage race. Your intake is less than your requirements therefore the difference needs to be made up. The only place to draw upon then is body stores. Given the above values, and the assumption that all glycogen is used up, the deficiency is being made up of fat and muscle. A deficiency of 2,600 kcal/day (4,600-2,000) if made up of pure muscle (think very lean racer) would result in a weight loss of 0.65 kg (1.43 lbs) per day or a total of about 4.5 kg (10 lbs)! This is not typical since most all carry some fat which helps greatly. If we assume fat and muscle are used equally, then these numbers reduce to approximately 0.4 kg (0.88 lbs) per day or about 2.8 kg (6.2 lbs) for the entire event which may still be high. All this obviously depends upon your metabolism.
What to eat and When
There are many things to ponder here. Some general considerations are that you must at least be able to tolerate what you plan on consuming. It should be simple and easy to prepare. Your menus ought to provide variety and support your personal culinary preferences. These are the easy things.
Harder to decipher is what type of foods (carbohydrates, protein and fats) should be consumed and when. Before going much further we should cover what each of these can (and can’t) do for you.
Carbohydrates: These are simple (fructose, glucose, etc.) and complex (breads, pasta) sugars. Carbohydrates are relatively easy to digest and provide for quick energy when compared to proteins and fats. They are not long lasting. If not used, carbohydrates are converted to glycogen and stored in the muscles and liver.
Protein: There are two main purposes for protein in the stage racer’s diet. One is the repair of muscles and other body tissues (blood cells, etc.) the other is a source of energy. While not as efficient or rapid as carbohydrates, excess protein is converted to energy as needed. Protein also plays an important role in hormones, enzymes, transport molecules (such as hemoglobin) and antibodies.
Fats: Fats are the bodies main source of energy for low to moderate intensity. They are very efficient for storing energy and work along with proteins to provide a long lasting source of energy.
To optimize your fuel, you may need to mix and match from the above. That is why a snack of chocolate and nuts is more satisfying and longer lasting than just a piece of chocolate by itself.
Your fueling needs during a stage race are time of day dependent. These can be grouped into four general time frames each with specific nutritional needs. While all types of racers have similar needs (such as prior to racing and recovery/night time) conventional wisdom dictates that during the day’s stage there will be different needs based on the exertion level.
Pre-stage: Commonly known as breakfast this is ever so important. Not only are you recharging from the previous night, you are taking on stores to help get you through the day’s stage. A balance of carbohydrates and slower digested fats and proteins are in order. Efforts should be made to fuel as close to the start time as possible. Resist the temptation to eat the minute you wake. Having a large caloric breakfast also reduces the amount of weight carried on your back.
Stage: This fueling time frame necessitates subdivision into three sub-categories due to their unique requirements.
Racer: With a much higher pace, there is a much higher demand for carbohydrates to keep output high. While nuts and other high calorie foods would be nice they cannot keep up with the body’s demand. They are also harder to consume therefore liquid fuels and gels are preferred in this situation. Liquid fuels also allow for a more continuous rate of intake and thus allow for maintenance of a more constant blood sugar level. While gels are convenient, they are relatively heavy. Dehydrated fuels (powders) are preferred.
Mid-Packer: This is neither an elite racer as above or a walker which follows. This person while moving at a slower pace than an elite will still require a fair amount of carbohydrates to maintain their speed. However, a mid-packer can also tolerate higher calorie fat/protein foods. The balance needs to be developed at an individual level.
Walker: At a much slower pace and thus lower caloric demands, the walker has the advantage of being able to consume higher calorie fat/protein foods. This should be a serious consideration because of the time spent out on the course and resulting limited recovery time before bed. Solid foods can be more easily consumed at a walking pace and prove to be more satisfying than a liquid diet.
Recovery: This is about the same for everyone. You need to get some carbohydrates in you to bring your blood sugar levels back up to a comfortable level as well as some protein to aid in a little bit of muscle rebuilding (if possible). You should also consider taking in some fats so to hold you over until the evening meal. Some elite athletes will have two recovery fueling periods.
Evening/night: The objective here is to give yourself nutritional combinations that provide energy all night long. In addition to a continued recovery, you will need to keep yourself warm and as such fats and proteins here are better than carbohydrates. Additionally, carbohydrates will result in a spike and then crash in blood sugar levels later in the night causing you to wake up (usually in the wee hours of the morning) hungry. Unfortunately, when in this situation, it is hard to get back to sleep! Try to consume your dinner as late in the evening as is comfortable.
Obtaining the proper balance of carbohydrates, fats and protein may be difficult due to the limitations of foods that are available. Sometimes it is advisable to use a paring approach or include various additives to reach your desired end state. For example, if you wish additional protein, jerky or a protein powder can supplement your meal. If fats are needed than a shot of olive oil or some nut butter will work. Creativity here will also help to shake things up. If you are tiered of oatmeal than why not have spaghetti for breakfast!
Non-linear Fueling Strategy
As an engineer, I find stage racing is an interesting optimization problem. It all boils down to how can I get the most performance given various constraints. For sleeping systems this is obvious. I need the lightest system that just keeps me warm enough so I can sleep relatively comfortably. Weight, volume, cost and robustness also play into the equation and must be accounted for.
For nutrition/food this is more complicated yet can yield some striking results. Many start by bringing the minimum required calories plus a little more. This may allow you to reach the finish but will it allow you to reach the finish in the fastest possible time? Will carrying an additional 400-700 Kcals/day allow you to perform better despite the increased weight? These are hard questions to answer and require individual experimentation.
For myself, I found that 14,000 kcals are not sufficient to race on. I have in the past typically carried 16,800 – 18,000 calories depending upon the race and ambient temperatures. I am therefore taking along an additional 2,800 – 4,000 kcals (0.7 – 1.0 kg / 1.5 – 2.2 lbs). Even at this increased supply I typically lose 4 – 6 lbs (1.8 – 2.7 kg) of body mass over the event.
But just bring along extra calories may not be optimal. Many (especially those at the 14,000 kcal minimum level) consume approximately a constant number of calories per day. There may be some variation for the long stage/rest day but it is usually not that great. A proposed approach that may prove superior is to consume calories in an extremely non-linear (non-constant) fashion. Basically, one eats more earlier in the race and then taper off until some minimum level is reached. This has several benefits including providing the energy required when there is a higher level of effort demanded (heavier pack), minimizing muscle mass loss early/overall and reducing the weight carried rapidly. Obviously this can only be employed if one carries more than the minimum number of calories.
For the purpose of comparison, we will evaluate the following scenarios. It should be noted that no one strategy may be exactly what individuals follow but it will give an approximate evaluation.
- 14,000 total kcals consumed in a linear fashion
- 14,000 total kcals consumed in a non-linear fashion
- 16,800 total kcals consumed in a linear fashion
- 16,800 total kcals consumed in a non-linear fashion
This comparison will be for a typical seven day/six stage race with the long stage on days four and five. We will look at caloric deficit and food weight for each of these strategies based on the above 70 kg / 154 lb male racer requiring approximately 28,000 kcals for the entire race. Data for these various strategies are presented in Table 4.
When comparing the caloric deficits of the four strategies there is some striking results. Figure 1 shows that the level of caloric deficit is delayed by one to two days when employing a non-linear consumption strategy compared to a linear one. This is especially noticeable between the minimal 14,000 kcals and higher 16,800 kcals level. Think of it, how much degraded is your performance after two days of “starving”? At the beginning of the long stage the 16,800 kcal/non-linear strategy has a 4,000 kcal smaller deficit that the 14,000 kcal/linear strategy. This is equivalent of around 0.5 kg (1.1 lb) of body weight (muscle)!
But that is only half of the picture. Figure 2 displays the weight of food at the start of each day. It is very evident that even with the increased weight of 16,800 kcals the higher consumption rate of a non-linear strategy quickly brings this down to the equivalent 14,000 kcal weight by the start of the third day. It then stays lighter for the reminder of the event when compared to linear consumption strategies and matches the weight of the 14,000 kcal non-linear strategy.
Obviously, these comparisons depend on various factors including stage lengths, actual eating habits and race minimum calorie requirements. It does however give us a potential strategy for enhancing performance during these demanding events. Proof and optimization of this hypothesis will take some time and experimentation.
If any of you do try and employ this strategy I would be grateful to hear of your results.