Most endurance athletes, be it professionals or amateurs, are well-versed about what their ideal diet should be. They know all about calories and macronutrients. They make all possible efforts for proper fuelling and recovering from long training runs or races. However, they may not be aware about how to time their meals to maximize performance and optimize post-run recovery. This is where the concept of nutrient-timing comes into play.

The theory behind nutrient-timing is quite interesting. It involves eating specific macronutrients in specified quantities at particular times before, during, and after endurance events or key training sessions. Following this practice along with careful consideration of the types of foods you eat has a significant effect on health, performance, recovery, and fat loss. 

Do note that nutrient-timing is not necessary if you are a regular gym-goer, who is meeting recovery-related nutritional needs through the usual diet. Nutrient-timing is only appropriate for you if you are an endurance athlete who has already attained an elevated level of physical fitness and are adhering to a healthy diet that supports your body composition and athletic performance. There is no benefit to nutrient-timing if you have not already mastered your overall caloric and macronutrient intake. 

Additionally, the research surrounding nutrient timing has, at times, been inconclusive and tough to decipher. That said, there are some evidence-based guidelines that you can follow.

Why nutrient timing is important

According to the International Society of Sports Nutrition (ISSN), “Nutrient timing incorporates the use of methodical planning and eating of whole foods, fortified foods, and dietary supplements. The timing of energy intake and the ratio of certain ingested macronutrients may enhance recovery and tissue repair, augment muscle protein synthesis, and improve mood states following high-volume or intense exercise.”

Even if you have immense mental toughness, your performance will falter once your glycogen stores are depleted. This holds true not only for an event day but also throughout your training regimen. 

Phase-wise nutrient-timing plan

If you are a marathon runner, you require increased fluid intake to replace sweat losses and increased energy to fuel exercise. Fortunately, a well-designed eating and hydration plan, combined with an appropriate training program and adequate recovery, can lead to peak athletic performance. 

Here are a few ideas that you may consider implementing before, during, and after the marathon.

1. Recommended pre-marathon approach

Carbohydrates are the most important nutrient in a marathon runner’s diet. So, as an endurance runner, you need to consistently consume a high-carbohydrate diet, which is about 8g to 12g per kg of body weight per day. For instance, if you weigh 70kg, your carbohydrate requirement equates to anywhere in the range of 560g-840g per day. If your events and training sessions last longer than 90 minutes, it is advisable to raise your carbohydrate intake to 10g to 12g per kg of body weight per day for 36 to 48 hours leading up to the event. In addition, consume 1g-4g of carbohydrate per kg of body weight one to four hours before exercise. 

Here is a tabular representation, taking important aspects into account:

In the week leading up to race day, consider adhering to a three-stage carbohydrate loading regime. These include:

Stage 1 

It is the glycogen-depletion stage. During this period, you perform moderate-to-high-intensity exercises while eating a low-to-moderate carbohydrate diet, which is typically less than 55% of total calories. The goal of this stage is to deplete the glycogen stores in the muscles. This phase is from the first day to the third day of the seven-day protocol.

Stage 2 

It is the glycogen-loading stage. During this duration, you need to increase your carbohydrate consumption to 70% or more of total calories and decrease your exercise load to low-intensity, short-duration workouts. This stage is from the fourth day to the sixth day of the seven-day protocol. 

Stage 3

Finally, day seven is race day. The last pre-event meal, which is usually dinner the night before, should contain more than 80% of calories from carbohydrates.

Read: Carbohydrate-loading for a Marathon: A Step-by-step Guide

2. What to do during the marathon

Many people struggle with the concept of fueling during long-distance runs and events when they first start to train for marathons. Gastrointestinal distress may be a concern, and some people do not feel like eating. However, providing fuel during a marathon is essential.

It is suggested to consume approximately 30g to 60g of carbohydrates per hour that you run. So, if it takes you three hours to complete a run, have 90g to 180g of carbohydrates during the event. If you are running in extreme heat or cold or at a high altitude, your intake of carbohydrates must be towards the higher limit of the prescribed range. This also holds true if you did not consume enough food or fluids or did not do carbohydrate-loading prior to the run. 

Begin consuming carbohydrates early on during the event in small amounts after every 15 to 20 minutes instead of eating them all at once later, or as you start to feel fatigued. So, if you are planning to run the marathon in three hours and begin refueling at the 20-minute mark and every 20 minutes thereafter, consuming around 15g of carbohydrates at each interval would indicate that you will intake 135g of carbohydrates throughout the run. You can adjust the amount of carbohydrates in each snack to accomplish your goal where you should arrive through trial and error during your training. Here is a tabular depiction: 

Also read: How to Avoid Losing Weight While Marathon Training

3. Post-marathon suggestions

After the run, your objectives must be to replenish depleted glycogen stores by consuming carbohydrates and facilitate muscle repair and growth through protein intake. The best post-workout meals are high in carbohydrates and include some amount of protein. For example, the meal may contain 1g of carbohydrate and 0.5g of protein per kg of body weight.

Then, after the initial meal, eat a similar meal every two hours for four to six hours. Post that, you can return to your typical healthy and balanced diet.

Now you may have understood the importance of nutrient-timing and how it works. So, if you are training for a marathon, adopt these strategies during different phases to be successful. 

References
1. Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. J Acad Nutr Diet 2016; 116: 501–28. 
2. Ivy JL, Goforth HW Jr, Damon BM, et al. Early postexercise muscle glycogen recovery is enhanced with a carbohydrate-protein supplement. J Appl Physiol (1985) 2002; 93: 1337–44.
3. Kerksick CM, Wilborn CD, Roberts MD, et al. ISSN exercise & sports nutrition review update: research & recommendations. J Int Soc Sports Nutr 2018; 15: 38.
4. Muth ND. Sports Nutrition for Health Professionals. Philadelphia: FA Davis, 2015.
5. American Dietetic Association; Dietitians of Canada; American College of Sports Medicine, et al. American College of Sports Medicine position stand. Nutrition and athletic performance. Med Sci Sports Exerc 2009; 41: 709–31.