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Nutrition during long events is critical to success, but there is a lot of confusion and mistaken information on exactly how this is best done. This article seeks to explain the process from my perspective as an age group athlete who raced in long course triathlon, MTB stage races, and the occasional trail run. The application of these ideas will make your long training days more productive and racing more successful.

The secret to high energy output in ultra-events is to be able to produce more energy than you receive from the fuel that is consumed as you exercise. You can only digest food at the rate of about 120-180 Calories per hour, (a minority of athletes can digest more), but it may be necessary to produce about 600 Calories per hour of energy to proceed in an event. To do this you must understand both how to fuel and how to carefully manage the stored energy sources your body utilises. Most athletes do not know that they can control the physiological processes that are taking place in their body, and this lack of understanding causes many sub-par performances and even DNFs.

To understand how you can produce more energy than you consume let us review how energy production in the body works. The aerobic system is the most important for ultra-endurance sports so this article will focus on how to activate and use this remarkable system. But first, let us talk about all of the systems available while exercising:

  • The phosphocreatine energy production system is good for about 10 seconds of very high energy production, EG a 100m sprint.
  • The anaerobic system, or lactic acid cycle, is a powerful but inefficient way to produce energy. It is the primary source of energy for shorter events like sprint triathlons, 10 K runs or 40 K cycling TTs. You should not rely on this system for most of your training and try to minimize its use during ultra-events.
  • The anaerobic system can be readily activated at any time by increasing effort, but this will result in lactic acid build up in the muscles. The athlete will be depleted of glycogen and unable to produce high levels of energy from the aerobic energy system for a long time. There is also a sort of anaerobic “hangover” that appears as soreness in your muscles. Activating this system by sprinting up a hill or chasing other competitors must be avoided in ultra-events. These impulsive acts will provide short-term gratification at the cost of lactic acid build-up.
  • Once you go anaerobic, the by-products will inhibit energy production for many hours thereafter. No amount of fuelling as you exercise can effectively restore your ability to continue racing or training that day at a high level of output.
  • The aerobic energy production system is the key to doing longer races. The major objective of training is to increase energy production of this more efficient energy production system. As with anaerobic exercise, this involves using the glycogen to ATP energy production system, but when glycogen is used aerobically, which means converting it to ATP by using oxygen, you have the potential for long term endurance lasting many hours. But, there are only a couple thousand calories of glycogen stored in the muscles and liver so you need to avoid depleting your glycogen stores quickly. Maintain the highest level of glycogen possible in your body so that ample amounts are always available to be converted into energy as your race or training proceeds.

There are two ways to replace the glycogen (energy) you are burning as you exercise:

1) Consuming and digesting food which becomes glycogen.

2) Accessing stored energy by digesting your own body tissues.

For success in longer events, you must do both. By tapping into both of these two ways you can produce energy at high levels of output for lengthy periods of time. In order to get into the mode of consuming body tissues, especially fat, exercise should start at a moderate rate which gradually lowers the glycogen level in your body. Physical processes are set in motion whereby your body starts searching for more fuel and begins to access energy by consuming your own fat stores. This is called catabolysis. A lean athlete’s body can contain 100,000 Calories stored as fat, so there is no shortage of fuel available. Once this process is begun, you can start to consume calories by eating and both sources of energy will be actively contributing glycogen. Many strong athletes do their training in a manner that does not teach their body how to create energy efficiently by training too hard and they eventually reach a plateau. The best endurance athletes get past this plateau by observing proper training levels and in their fuelling. To get better at ultra-events, you might need to add a lot of moderate level exercise to train your physical systems to effectively utilize your stored body fat. A limited amount (10-20%) of very high-level work is needed to maintain your elevated lactic threshold.

This article is not targeting training levels, but when you combine correct fuelling with training at the right levels you will see a remarkable improvement in results. Careful optimization of training levels and fuelling can result in a 10% improvement in performance even after years as an endurance athlete. Within the aerobic range of effort, less than 70 % of maximum, there is an important level at about 50% effort where you are maximizing the consumption of your body fat. The sum of the glycogen converted from fat stores plus the fuel you are digesting results in replenishing your total glycogen stores at the same rate as your overall energy output. If you have trained properly, you can sustain this level of energy output almost indefinitely. The fraction of energy from the anaerobic system is sufficiently low that the by-products are reabsorbed by your cells as they are produced.

While exercising at this level you will be utilizing about 300+ calories of body fat per hour and the rest through the use of fuels. Knowing where this boundary is, is the key to maintaining energy to the end of a long event without depleting your glycogen system and “hitting the wall”. The fuels you use are also important. They must contain readily digestible complex carbohydrates and a significant amount of protein present in easily digestible form. The protein you are consuming limits the catabolysis of your body’s muscle tissue and helps to maximize catabolysis of your fat stores. The Hammer Nutrition endurance fuels are specifically designed to supply you with optimum nutrition while you exercise.

Summary of the Principles of Effective Fuel use in Ultra Events:

  • Do not consume food within three hours before exercise.
    • Start gradually to gently lower glycogen stores and get fat-burning started.
    • Do the majority of your endurance training at about 50% level.
    • Consume fuel at the rate of 120-180 calories per hour.
    • Avoid sudden increases of effort that get you out of fat-burning mode.
    • Use properly formulated fuel: a complex carbohydrate with 15% protein

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