Athletes spend countless hours in the gym training and conditioning their bodies to achieve the highest level of performance possible, but they often don’t realize that nutrition — in addition to training — plays a key role in how they perform.
When looking at nutrition for athletes specifically, it’s not just about what you eat, but also when you eat. Meal timing is a critical part of how well you perform and how well you recover.
Carbohydrates for Performance
Carbohydrates act as fuel for almost every cell in the body. The amount of glycogen (the storage form of glucose) in the muscles and liver dictates how well we perform, so it’s crucial to maintain adequate stores. When muscle glycogen is high, an athlete can perform at their desired intensity for an extended period of time. When muscle glycogen is low, on the other hand, fatigue sets in easily and significantly reduces training intensity.
As carbohydrates provide the majority of fuel for athletes during exercise, it’s important to ensure that you’re consuming the correct type and quantity. As such, we look to differentiate between simple carbohydrates and complex carbohydrates. Simple carbs are those that absorb rapidly and produce a rapid spike in insulin levels and subsequently allow glucose to enter the bloodstream quicker, whereas complex carbohydrates take longer to digest and produce a less rapid insulin response. But rather than looking towards simple and complex for performance, we can also use the glycemic index to determine what carbs you should eat around your workouts.
Glycemic Index: The ranking of foods from 0-100 based on their immediate effect on blood sugar; it is the rate at which a food is digested and converted to glucose in the body.
Our Picks: High GI Carbohydrates (consume before/during/after workouts)
Short-grain rice (jasmine, arborio, medium-grain)
Starchy vegetables (white potatoes, plantain, sweet potato, yams, taro, rutabaga)
Fruits (bananas, mango, melons, pineapple, peaches, kiwi)
Our Picks: Low GI Carbohydrates (consume away from workouts)
Long-grain rice, brown rice, barley
Pseudo grains (quinoa, amaranth, buckwheat)
Bread (rye, sourdough)
Fruits (blackberries, raspberries, strawberries, blueberries, apples, grapefruit)
Vegetables (carrots, broccoli, cauliflower, peppers, zucchini, green leafy, tomatoes, etc.)
Starchy vegetables (parsnips, pumpkin, carrots)
Legumes (lentils, chickpeas, kidney beans, black beans, etc.)
When you consume high glycemic foods before and after a workout, insulin levels spike to allow glucose to enter cells. In doing so, they provide fuel to power through a workout, as well as a source to replenish glycogen stores once exercise has halted. However, there can also be something said for consuming a lower glycemic meal prior to exercise, as studies have shown that slower digesting carbs produce a more sustained release of energy in endurance athletes (Bean, 2013).
Re-Fuelling After Exercise
Any athlete should know that eating after a training session is crucial to recovery, but in what period must you eat to avoid any detrimental effects?
How long it takes to re-fuel depends on four factors (Bean, 2013):
1. How depleted glycogen stores are
The more you deplete your glycogen stores, the longer it will take to replenish them. However, the extent of depletion depends on the intensity and duration of the workout. The more intense the workout, the lower glycogen stores will be. The minimum amount of time to replenish glycogen stores is around 20 hours for low-intensity activity, while the maximum can take up to 7 days for high-intensity activity. Similarly, the duration of your workout also impacts glycogen stores. The longer the workout, the more glycogen will be used.
2. The extent of muscle damage
Muscle damage also plays a role in glycogen depletion. Eccentric exercises, heavy weight lifting, or plyometric training, for example, cause damage to muscle fibres. When this occurs, incoming glucose goes to repair muscles rather than to storage — and when the extent of muscle damage is greater, replenishing glycogen stores takes more time. This can take anywhere from 7-10 days.
3. Amount and timing of carbohydrates consumed
As carbohydrates function to replenish glycogen, the amount an athlete eats will determine how fast stores are replaced. If you train consistently (daily or multiple times per day), it’s crucial to consume adequate carbohydrates to prevent depletion. Over successive days of training, glycogen stores will continue to decline if too few carbohydrates are consumed for full replenishment. If you consume inadequate amounts, athletic performance will suffer.
4. Training experience and fitness level
As training experience and levels improve, so, too, do refuelling capabilities. The more an athlete trains, the better his or her body will be at replenishing glycogen stores. As training experience increases, glycogen store capacity also improves, meaning the body can store more glycogen.
“The Metabolic Window of Opportunity”
In the fitness and nutrition world, there’s a theory called the ‘metabolic window of opportunity’ whereby the body best absorbs nutrients in a specific time period after activity. Previous research differentiates between two distinct components: the first area is glycogen storage refilling and suggests that consuming carbohydrates immediately after exercise nearly doubles the rate of replenishment ; the second area is the ‘anabolic’ window for new muscle growth and suggests that consuming protein immediately after a workout leads to more rapid muscle building as opposed to waiting several hours .
But more recently, this theory has been challenged because it doesn’t account for feeding pre-workout. When an athlete consumes adequate protein and carbohydrates before a workout, the emphasis on the eating window post-workout diminishes. Since the anabolic window lasts up to six hours post-activity, the refuelling window becomes much larger. That’s not to say you should wait six hours after training to eat, but accounting for what’s eaten before a workout changes the game a bit.
If you’re not planning to train within an 8-hour period after your last training session, consuming carbs immediately after a workout is not imperative. As long as the total carb count for the day is met, the replenishment levels after 24 hours will be roughly the same.
Protein and Muscle Building
Protein has long been associated with building muscle — and while that’s a correct statement, eating more protein doesn’t equate directly to more muscle mass. It’s a little more complicated than that.
Depending on whether you’re doing endurance training or strength and power training, protein requirements will vary. As strength training causes more damage to muscle fibres than endurance training, protein needs increase to match the rate of protein breakdown and synthesis . Increasing protein intake also puts the body into a positive nitrogen state (the amount of incoming nitrogen exceeds what’s being excreted), which is necessary to promote muscle growth.
As with carbohydrates, the timing of protein intake is important. Studies show that muscles are most receptive to protein within the first two hours after exercise, but can extend up to 24 hours. Combining protein with carbohydrates, generally a 2:1 ratio, promotes muscle building and proper recovery in athletes. Unlike carbs, however, it’s advised that protein intake be spaced evenly throughout the day rather than solely round training periods.
But not all protein is created equally. If you’ve know anything about protein supplements, you’ve likely heard the terms whey and casein. These are examples of a fast-digesting protein and a slow-digesting one. When refuelling from a training session, it’s best to consume fast-digesting proteins where amino acids will be absorbed quicker and promote greater muscle synthesis.
Not sure what proteins are fast-digesting and which aren’t? Here are some good post-workout options:
Grass-fed whey protein (concentrate, isolate, hydrolysate)
Poultry (chicken, turkey)
Fish (salmon, tuna)
Dairy (if tolerable)
The Low-Down On Fats
We’re not going to talk much about fats because, while they are important for body function, they delay digestion and absorption and are not optimal to consume before or after a workout. But fats are necessary for proper body function, for both athletes and non.
Saturated vs. Unsaturated Fats
You find saturated fats in animal products like meats, dairy, and eggs, as well as coconut. While they’re often criminalized, they are important for many functions in the body: regulating the immune system, improving brain function, proper nerve signalling, and much more.
Unsaturated fats are the ones we’re told to consume plenty of. Monounsaturated fats, like those found in olive oil, nuts, and seeds, and polyunsaturated fats that are found in foods like vegetable oils and cold-water fish, are both important in cholesterol regulation. Omega-3 and Omega-6, subcategories of polyunsaturated fats, are crucial for things like blood clotting, reducing inflammation, controlling the tone of blood vessel walls, and boosting the immune system .
Like every other food, fats aren’t all the same and you should consume some more frequently than others. As an athlete, optimal body function is crucial to your health and performance, so getting adequate amounts of dietary fat is important. Here are some of the best choices:
Omega-3 Fatty Acids
Cold-water fatty fish (mackerel, salmon, trout, tuna, herring, sardines)
Nuts (almonds, brazil, hazelnuts, walnuts, pecans)
Seeds (chia, hemp, flax, pumpkin, sunflower)
Other good fat sources include:
So What Should You Eat?
With all that said, eating to fuel performance shouldn’t be a science. Nutrition comes down to eating what works for your body, avoiding what doesn’t, and giving your body the proper amount of substance it needs to perform at its best.
Protein + carbs + small amount of fat
Smoothie (e.g. avocado, blueberries, banana, almond milk or banana, PB, oats, flaxseed, almond milk)
Oatmeal + fruit + PB
Greek yoghurt + fruit + homemade granola
Protein + carbs
Baked salmon + rice + broccoli
Grilled chicken + quinoa + roasted veggies
Smoothie (strawberries/blueberries, kale, spinach, protein powder, chia/flax, almond milk)
Vegetable omelette with side potatoes
6oz. steak + baked sweet potato + sautéed spinach
Fruits + nut butter (no added sugar)
Remember that what we’re giving you here is just nutrition guidelines for optimal performance. Like athletes’ training routines, their nutritional requirements will all be different. Some people perform best with higher carbs, while others don’t. Some perform best eating three meals per day, while others perform best eating six. Nutrition isn’t static, so finding your nutritional groove can be just as difficult as maintaining it.
Bean, A. (2013). The complete guide to sports nutrition. London: Bloomsbury Sport, an imprint of Bloomsbury Publishing Plc.