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Nutrient Timing Is Everything For Runners

How an athlete's body utilizes energy is infinitely more critical than that of their sedentary peers.

How an athlete’s body utilizes energy is infinitely more critical than that of their sedentary peers.

It’s not just what you eat, nor how much, but also when you eat.

Nutrient timing takes into account the times for which an athlete needs the greatest amount of energy while also balancing their energy throughout the rest of the day. “Being more sufficient with the macro nutrition…we know we can put out a better workout,” explains performance nutritionist Krista Austin, PhD. “The bonus for the body is it helps optimize our body composition.”

Energy flux is the rate at which the body turns over fuel. Ideally an athlete wants to keep pace with calories in versus calories out. This allows the runner to meet energy demands during training and maintain body composition. So long as overall calories are kept in check, you reduce the risk of storing excess body fat.

RELATED: 5 Tips For Maintaining Your Daily Diet

Meb Keflezighi is a prime example of effective nutrient timing. “Now, his carbs are much more controlled versus when he was younger,” shares Austin.

Implementing Nutritional Timing

Austin says to begin prioritizing your meals, there are several key factors to consider:

1)   Training Phase: The macrocycle of your nutrition plan looks long term, lasting multiple months. Akin to your training program, which is aimed to have you peaking for a key race, your weekly nutrition will vary in accordance to your training. Microcycles, lasting 3-10 days, also come into play and take into account which energy system that week’s training is stressing. “In marathon training, a microcycle focused on 10K training, with velocity and speed upped, you need more carbs in the diet, where the overall marathon macrocycle is to get as lean as possible [with] low GI carbs and protein.”

2)   Energy System: Aerobic-focused training blocks, such as in early season base training, will have one’s diet leaning to the low GI carbohydrates and heavier amounts of protein. Conversely, periods of training with especially taxing interval sessions, anaerobic training phases, would be times where the microcycle allows for more high GI foods such as potatoes, rice, and bread.

3)   Body Composition Goals: “Take calories in at the rate we are burning them.” Athletes that match nutrient intake to current energy flux are able to better obtain the lean, performance-minded body composition.

4)   Recovery: Timing of nutrients is especially crucial when tied to muscle repair and the body’s ability to build back stronger. “If we time protein after training, that’s an optimal time to take in protein to repair muscles.” Within 30 minutes post-workout get 20-25g protein with some carbs; then, have a meal within two hours. Before going to bed aim for another 20-25g of protein.

* Protein: Partitioning is when a specific macronutrient is more heavily relied on during a meal or throughout the day. Protein plays a major role in appetite control, recovery, and body composition. Athletes needing to lose weight will want to front-load their menus with extra protein, making sure their breakfast consists of 35% protein and continuing with protein-heavy meals and snacks throughout the day.

* Carbs: Time your carbs specifically around your workouts. During aerobic phases, opt for low-GI foods; in an anaerobic phase you can be more free with the high GI carbs, but this is during training or immediately afterward.

* Backloading: Aim to always keep pace with energy expenditures and avoid going into a deficit. With long runs this can be difficult, as it’s imperative to refuel within a 30-minute window and then fully restocking reserves with a meal right a couple hours later. “You don’t want to wait and do it four hours later, when the body’s metabolism just shuts down. That’s why we don’t want to do backloading; [athletes] also miss that time to help repair those muscles and the whole body.”

RELATED: 4 Eating Habits That Reduce Injury Risk

Same Athlete, Different Microcycle

Sample menu for a hard interval day:

*Breakfast: 60% carbohydrate/20% protein/20% fat – whole grain bagel with cream cheese


*Snack: Low GI carb choice— cottage cheese and fruit

*Lunch: Potato Soup, whole grain crackers and low residue fruit (ex: grapes, cantaloupe)

*Pre-Workout: Electrolyte drink

*During Intervals: Energy gel diluted drank throughout [high GI carb]

*Post-Workout: 20-25g whey protein and 1g carbs per kilogram bodyweight

*Dinner: 60% carbs/20% protein/20% fat –complex carbs (ex: baked potato, rice, bread)

*Snack: chocolate milk [sugar and protein to aid recovery]

Sample menu for an aerobic/easy day:

*Breakfast: 45% carbs/35% protein/20% fat – omelet with fruit

*Easy run

*Snack: Low GI carb choice— cottage cheese and fruit

*Lunch: 35% protein – chicken salad, side of Greek yogurt, fruit

*Snack: Peanut butter on rice cake

*Easy run

*Dinner: 35% protein – grilled salmon, veggies, one roll, and fruit

*Snack: skim milk [with 20-25g protein if need more calories]

Austin warns of a misstep many athletes can make, even with timing their fuel.

“A mistake is usually just going crazy with the calories,” Austin says. “It’s all about taking their total calorie need for the day and optimizing how we use them at each time point.”


About The Author:

Caitlin Chock set the then national high school 5K record of 15:52.88 in 2004. Now a freelance writer and artist she writes about all things running and designs her own line of running shirts. You can read more, see her running comics, and her shirts at her website.