First and foremost, nutrition needs to be an all day thing. An intense training session followed by a protein shake is not going to be the thing that takes your game to the next level. Don’t neglect nutrition the rest of the day and expect one protein shake to make the difference in your performance. I often say this, but I think it is worth repeating. Eat with intent! Eat with the thought of your past, present and future training sessions in mind.
With that being said, nutrient timing before, during and after training can play an important role in athletic performance. Just because your workout from this morning is over doesn’t mean that your body is done with its part. If done properly, your glycogen stores (both liver and muscle) should be depleted but it is up to you to restore them! Depending on your sport, you may even need to start to replenish your stores in the middle of your workout. Nutrient timing is an important component of athletic performance. This article will review some parts of the position stand on nutrient timing from the International Society of Sports Nutrition (Kerksick 2017).
What Nutrients Should We Focus on For Nutrient Timing?
When it comes to nutrients, the two that come to mind usually are carbohydrates and protein. And this is for good reason, carbs and proteins are important for recovery. The timing for when you should eat these key nutrients will depend on your sport and your performance goals.
Carbohydrates
The main reasoning behind variations in nutrient timing has a lot to do with glycogen stores. Glycogen is found in our muscles and liver is our stored form of carbohydrates. Glycogen is released when our bodies need fuel. High volume exercise is often the reason why these stores are depleted. Glycogen is the predominant source of fuel during moderate to high-intensity aerobic exercise (65-85% VO2max), and high volume resistance training has been shown to deplete glycogen stores as well.
When glycogen levels decrease, we cannot maintain the same level of exercise intensity. This means that if you are not refueling adequately for your sport, your game will suffer. If glycogen is so important, how can we make sure our bodies have enough stored and ready to go?
Typical recommendations say that glycogen can be optimally restored with a high-carbohydrate diet of 8-10 g of carbs/kg/day. For example, if you weigh 75 kg (~165 lbs.), then you will need 600-750 g of carbs in your day following high volume exercise. This is where the idea of carb loading comes into play. Endurance athletes can taper their training volume a couple of days prior to competition while increasing their intake of carbs to facilitate supersaturation of muscle glycogen.
On competition days, maintenance of glycogen stores can be achieved through food or drink items that are consumed several hours prior to the event. These items should contain carbohydrates that can help to meet 1-4 g/kg/day.
Note: the majority of studies on nutrient timing for carbohydrates have been performed on male endurance athletes, and results may not represent adequate intake ranges for female athletes and athletes who are involved in more anaerobic style events.
Protein
Something that is often considered as the optimal post-workout item is chocolate milk. Really? But why?
Yes! You would be hard pressed to go into a weight room or fuel station at a university and not find chocolate milk in the fridge. Chocolate milk has a nice combination of carbohydrates and protein to help aid in recovery. Are there other options available? Of course, but this is just to drive home the idea that carbohydrates and proteins have a nice symbiotic relationship.
Cyclists were recruited to complete a three-hour bout of 45-75% VO2 max training prior to exercising to exhaustion. In order to test how protein plays a role in performance, participants were either provided carbohydrates or a carbohydrates and protein mixture in solution. The group ingesting the mixture of carbs and protein had significant improvement in endurance, performance, and reductions in muscle damage. This result has been demonstrated in a number of studies. A separate study by Rustad and colleagues showed that athletes with protein (0.4 g/kg/hr) and carbohydrate (0.8 g/kg/hr) intake two hours prior to exhaustive cycling bouts had improved overall performance.
How Can Nutrient Timing Be Used For Resistance Training?
In a particular study, carbohydrates were administered before and after resistance training during two-a-day training sessions. The study demonstrated benefits to performance but only during the second session of the day. However, this is not always the case and the majority of studies done on pre and post carbohydrate administration for resistance training had difficulty showing improvements to resistance training performance.
So pre- and post-workout carbohydrates haven’t shown conclusive evidence, but what about during. There was a study done where participants undergoing resistance training for 40-minutes were administered a dose of carbohydrates (1.0 g/kg) prior to the workout as well as every 10-minutes during (0.5 g/kg). The study found that glycogen stores losses were 49% less when compared to the control group but did not have an impact on performance.
Overall, in order to maximize glycogen stores, it would be beneficial to have reduced training volume in conjunction with an increase in carbohydrate intake of at least 8 g/kg/day. This would likely be during the days after an event or during the offseason where days with reduced training are available.
Take Away
Further research needs to be done on sports and realms beyond endurance training, but nutrient timing shows promise. By taking the food and drinks you consume seriously, you can prime your body to its maximum potential in regards to glycogen stores. Eat with intention and get the most out of your body.
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