Fueling for performance is the act of eating specific foods or supplements during specific time windows to help maximize performance and support recovery in a certain activity. Different activities may require various fueling strategies depending on a number of different factors such as the event duration and intensity. A resistance-based gym session will have a different set of demands on the body than an endurance-based session.
While looking at the various fueling strategies, much of the attention is on acute fueling but it is important to remember that our day-to-day nutrition habits play a huge role in overall performance. Keep in mind, proper nutrition and hydration is important in the weeks leading up an event.
Acute fueling strategies are short-term modifications to your diet in the time close to your event. This may be the hours pre- or post-event, but will also include the days leading up to the event. Carbohydrate loading would be an example an acute fueling strategy.
ATP – Phosphocreatine System
This is the energy system of choice for immediate forms of activity. This is an anaerobic energy system, which means that it does not require oxygen. Short, explosive events or activities, lasting up to 10 secs in duration are going to be dependent on this energy system. Examples of these activities include max effort activities such as sprinting, jumping, throwing, weightlifting, punching etc.
Lactate - Anaerobic Glycolysis
This energy system does not require oxygen either. We call upon this energy system for short duration activities lasting approximately 1-3 minutes in duration. This involves converting glucose to lactate for energy. This system can be trained with exercise to improve our lactic acid threshold. Examples of activities dependent on this energy system are various field sports or activities requiring short bursts of high intensity activity that are often repeated.
Aerobic – Oxidative System
This energy system is a slower, but more efficient source of energy production for longer duration exercise. It does require oxygen and it can utilize carbohydrates, fats or proteins as energy sources. Examples of activities dependent on this energy system would be low intensity activity and endurance style events such as walking, marathons, triathlons or ultra-endurance events.
It is important to note that each system works simultaneously, with one being more predominant depending on exact demands at that time.
Carbohydrate is stored in the muscle and liver as glycogen. Carbohydrates are the body’s preferred fuel source and is the predominant energy source for all high intensity activity. Carbohydrates should make up approx. 45% to 65% of any diet with this intake being a mixture of both simple and complex carbohydrate sources. Exercise depletes glycogen stores; the rate of this depletion is dependent on the intensity and duration of the activity. Longer duration events (those lasting longer than 90 minutes) may benefit from carbohydrate loading protocol in the days leading up to event. Carbohydrate loading is the act of an increased carbohydrate intake in the days before an event to maximize glycogen stores in the body. Carbohydrate intake pre-/during-/post- activity is also going to dependent on the activity duration and intensity.
For those looking to support muscle, we generally recommend to eat 20-40g of protein approximately every 3-4 hours. The daily-recommended protein intake for healthy adults is 0.8g per kg bodyweight. This increase to an intake of 1.2 – 1.6g per kg bodyweight for active individuals, endurance athletes or older adults. Those participating in strength sports or looking to support muscle will have a higher daily-recommended intake of 1.6 – 2.2 g per kg bodyweight.
Fast-digesting proteins such as whey protein are commonly consumed closer to training times (pre or post-training). Slower digesting (casein protein) may be more commonly consumed as a pre bed snack.
Fats Should Make Up Approximately 30% of Your Total Daily Dietary Intake. Fat is an abundant energy source providing 9kcals per gram. This is more than double the amount of energy per gram than carbohydrates and protein (4kcal per g each). High-fat or ketogenic diets have increased in popularity in recent years, this way of eating may potentially be beneficial for ultra-endurance athletes and those fueling low-intensity activities. Becoming fat-adapted (changing the body’s primary use of fuel from glucose / glycogen to ketones) may take up to several months of dietary modifications.
The aim in the pre-workout window is to maximize energy stores. Eat based on your activity and sport – some activities will require more energy to be consumed. Longer duration events will require more energy than short duration events. It is generally recommended to consume a meal approximately 1-4 hours before activity. This meal should be comprised of complex carbohydrates, some protein and minimal fat. Consuming another snack about 30-60 minutes before the activity can further top up our energy. The focus here should be on simple carbohydrates, which are easily digested. There should be minimal fats or protein in a snack close to activity time due to the slower digestion rate of these macronutrients.
Nutrition during Exercise
Taking on certain foods and fluids during exercise can help to delay fatigue and other exercise-related physiological responses. For shorter duration events, the focus should be on consuming adequate water. While, carbohydrate beverages, electrolytes, and foods can be useful during longer durations of activity. The practicality of the foods you chose to take on also has to be considered. Chocolate bars will melt on a hot day and you may not have the capacity to peel an orange mid race.
Post Workout Nutrition
This window of time post-workout is hugely important to help support recovery and fuel your next training session. Recovery is an ongoing process that can take up to a couple of days. Protein post-workout can help support recovery and muscle building when taken over time with regular resistance training. 20-40g Protein per feeding is generally recommended. We recommend food first followed by supplement options. Replenish glycogen stores post-exercise with carbohydrates. The amount required is dependent on activity intensity and duration. The longer and higher intensity of the activity, the higher demand for carbohydrates post exercise will be. It is also very important to replenish lost fluids post-exercise. You may need additional drinks containing electrolytes, if competing in particularly humid conditions or if you have a high sweat rate.
Dehydration by as little as 2% can impact performance in all activities. Dehydration can lead to premature fatigue while also affecting decision-making in sporting settings. While there is not a recommendation for how much plain water adults should be consuming daily, there are general guidelines to follow to ensure that you are getting enough fluid. Adequate Intakes (AI) for general, healthy adults are based on gender and age. These estimates include water consumed through food and beverages, up to 20% of our fluid intake is consumed through food. If training in extreme (hot or cold) environments or you have a high sweat rate, consuming electrolytes/sports drink may be useful, particularly in longer duration ( >90 minutes) events. If you’ve lost a lot of water through sweat, consider using a sports drink with electrolytes to help replenish the electrolytes lost as well as aid in the absorption and retention of fluids.
Once food has been addressed, supplementation may be helpful in supporting additional performance benefits, depending on the chosen activity. Creatine, Caffeine and Beta-alanine are all commonly used. Carbohydrate-based electrolyte drinks, bars and gels are all commonly used in longer duration or more endurance based activities.
• Your fueling strategy should be unique to you.
• The fueling strategy required for a specific activity is dependent on a number of factors such as the intensity and duration of that activity.
• Utilize both short- and longer-term nutrition strategies to help support optimal performance.
• Focus nutrition around activity including pre-, intra- and post-activity.
• Focus on food first.
• Supplements may be a useful addition when foundations are correct.