Fuel Timing to Optimize Performance
Meal and nutrient timing can be key components of an athlete’s performance and recovery. When it comes to athletic performance, oftentimes the minor details lead to major payoffs. In the context of an athlete’s day, pre-, intra-, and post-exercise fueling can mean the difference between meeting or missing performance goals.
Pre-Exercise Fueling:The main goal of nutritional intake before a workout is to make sure there is enough fuel available for working muscles to utilize during exercise, as inadequate total intake can hinder performance (Arent 2020). During exercise, in addition to creatine phosphate, fatty acids and carbohydrates are used to produce energy to fuel muscle contractions (Arent 2020). Although fatty acids can provide energy to the body during low-intensity exercise, having adequate carbohydrate stores is necessary to optimize performance during moderate to high-intensity activity when carbohydrates are the primary fuel. This considered, the timing of pre-workout nutrition to ensure adequate carbohydrate fuel could start days before and can continue until activity onset; the longer the duration of the moderate to high-intensity activity, the longer the athlete needs to focus on pre-event carbohydrate. In the days leading up to a moderate to high-intensity competition, an athlete should focus on consuming balanced meals containing ample amounts of carbohydrate to fill glycogen stores, the storage form of carbohydrates. The number of carbohydrates needed would depend on the intensity and duration of the competition.
For example, soccer athletes who play 90-minute intense games would need more carbohydrates than basketball players who play stop and go. During the day of competition, meals can be more balanced the further out an athlete is from activity, being they have more time to properly digest more complex nutrients like fat and fiber. This type of meal, often ~4-hours before competition might consist of grilled chicken breast (protein), spaghetti with red sauce (carbohydrate), a serving of cooked vegetables (fiber), and a dinner roll with butter (carbohydrate and fat). Closer to competition (~30-minutes-2-hours prior), an athlete should choose an option with less fiber, fat, and protein that is primarily carbohydrate-based for ease of digestibility and quick energy production. In a practical sense, this carbohydrate-rich option might look like a granola bar, a banana, fruit snacks, or a sports drink.
The primary goal of intra-workout fueling is to prevent fatigue and cognitive decline, both entities that can negatively impact performance. If an athlete is properly fueled prior to exercise, intra-workout fueling is not always essential but should be a priority for longer (1 hour +), more intense training, or during glycogen-depleting competition. During these long-lasting competitions or intense training sessions, glycogen stores are depleted which can impair cognitive and physical function (Arent 2020). In fact, it has been reported that in team sports where a halftime period is taken, there is a decrease in performance and intensity, and an increased risk of injury in players during the first 15-20-minutes of the second half (Russell 2014). While there are numerous factors that may play into this, one practical halftime strategy used to combat these negative effects includes consuming carbohydrate-based fuel (Russell 2014). Similar to fueling just before exercise, easily digestible carbohydrates such as energy chews, pretzels, applesauce, or sports drinks are great options to support fueling needs during activity. For exercise bouts lasting over an hour, common recommendations include ingesting anywhere from 30-90g of carbohydrate/hour depending on both the length and intensity of the activity being completed in addition to the individual gastrointestinal tolerance of the athlete (i.e. consumption of 90g of carbohydrate/hour cannot be tolerated by all individuals). During lower intensity sports that last a longer amount of time, like golf, an athlete should look for options that provide more sustained energy through consuming a combination of carbohydrates, fat, and protein. A few examples of these more balanced fueling options include things such as trail mix, mixed nuts, or a deli sandwich to maintain performance.
For athletes who engage in glycogen-depleting or high-volume exercise on back-to-back days, the post-exercise period is often considered the most critical part of optimizing nutrient type and timing to support sustained athletic performance (Aragon 2013). During this period, the body is in a catabolic (breakdown) state, hallmarked by an increased rate of muscle protein breakdown (Arent 2020). To bring the body into an anabolic (building) state, post-exercise nutrition that includes carbohydrates and protein is essential. Once exercise stops, the rate of glucose uptake is increased for about two hours. This means that glucose is taken into the muscles more efficiently, thereby allowing glycogen stores to be replenished during this time if carbohydrate intake is sufficient (Arent 2020). To achieve proper replenishment of muscle glycogen after strenuous exercise, athletes should aim to consume ~1.0-1.5 g/kg/hr of carbohydrate within the first two hours after completion of the exercise. An example would be 68-102g of carbohydrate for a 150lb person. This could look like a bagel with peanut butter and a medium-sized banana (~ 80g total). Consumption of nutrients, namely carbohydrates (~1.0-1.5g/kg/hr), should continue for four to six hours with more frequent feedings being favorable for maximal glycogen resynthesis (Arent 2020).
Due to the body’s catabolic state post-workout, there is a marked increase in muscle damage and protein breakdown (Arent 2020). To counteract this, protein intake is crucial to combat further breakdown and help begin the process of repairing damaged muscles and building cellular components that support adaptation to exercise. During this time when the muscle is highly responsive to nutrient stimuli, high-quality and rapidly-digesting protein sources should be consumed to stimulate muscle protein synthesis (MPS). Several studies have shown that 20-40g of whey protein isolate is effective for maximally stimulating MPS (McLain 2015). The exact amount of protein needed for optimal MPS is not a uniform number due to many confounding factors that must be taken into account; to elaborate, the amount of protein required will depend on exercise intensity and duration, in addition to the gender and body size of each individual athlete. In regard to the timing of this 20-40g protein ingestion, there is a lack of consistency in research supporting an “anabolic window” post-workout (Argent 2013). However, despite this, it is generally accepted that sooner rather than later is most appropriate to properly begin rebuilding damaged muscle tissue, especially in athletes who participate in back-to-back training or competition days.
Meal timing around exercise is only a fraction of the food that an athlete eats in a day. If athletes are looking to optimize performance, fueling consistently and sufficiently throughout the day is imperative.
In addition to sufficient overall energy intake, spacing protein consistently throughout the day will maximize muscle protein synthesis and aid in recovery, adaptation, and performance. Research on the ingestion of protein prior to sleep has suggested that .6g/kg of protein is effective in (40g for 150lb person) maximizing overnight muscle protein synthesis (MPS) rates, thereby helping facilitate recovery and adaptation during this period (Arent 2020). For example, 7 oz of chicken will be 40g of protein.
Although it is clear that optimizing meal and nutrient timing around performance is important for promoting athletic success, training and total energy intake still serve as the primary foundation for maximizing performance outcomes. Therefore, athletes looking to gain a competitive edge should begin working on the nutrient timing and periodization tips provided only after a solid nutritional foundation has been laid.
Written by a Collegiate and Professional Sports Dietitians Association Registered Dietitian (RD). To learn more about sports nutrition and CPSDA, go to www.sportsrd.org.