Why is Post-Workout Fuel Important? | Day 13

I just finished a run with my friend this morning (if you’re reading, this one goes out to you, LC) and while thinking of what I was going to refuel with, she asked me, “What’s the science behind post-workout refueling?” Good question! I am often asked about the best post-workout meals and snacks. Many of us have heard that there is an optimal 30-45 minute window to refuel — or is it 90 minutes? You may have seen meatheads at the gym with their protein shakers, slurping them up immediately after their hour-long bicep curl sesh (and even in between reps!), trying to maximize those #gainz. So what’s the deal? Is there really an optimal refuel window, and if so, what does it do for us? I answer that (and offer some post-workout food ideas) below!

The Why:

Let’s start by answering WHY refueling is even important in the first place.

Post-workout nutrition serves three main purposes:

  • Replenish glycogen (energy stores)
  • Decrease protein breakdown (increase muscle size and/or quality)
  • Increase protein synthesis (repair damage caused by workout)

When we go for a run, lift weights or perform any type of workout, we use fuel and damage muscle tissue (which has to happen in order for our muscles to rebuild). When and what we eat places a key role in refueling our body and repairing our muscle tissue. This is ultimately what makes us leaner, stronger, fitter and injury-free.

The “Window of Opportunity”

Studies have shown that there is a window in which your muscles are primed to use nutrients, which starts immediately after your workout and lasts up to 2 hours. According to Precision Nutrition, “Research suggests that while protein synthesis persists for at least 48 hours after exercise, it’s most important to get post-workout nutrition immediately, within 2 hours afterwards.” If you do, you’ll get the benefits. If you delay it or do not adequately refuel, you risk decreased muscle glycogen storage and protein synthesis.

Why Carbohydrate and Protein together?

  • Protein aids in protein synthesis
  • Carbohydrates replace muscle glycogen (and help insulin transport nutrients into cells)

A chart showing the effectiveness of carbs and protein together versus alone:


Ideally in the first 30 minutes, within 1-2 hours:

Consume a snack or meal containing 3:1 or 4:1 Ratio of Carbs to Protein, depending on the intensity and duration of exercise (for more endurance-based exercise like running 45 minutes and up, aim for 4:1). For shorter duration and intensity, less carbs are needed.

Post-Workout Snack and Meal Options (pair a carb and a protein):

1/2 cup oats with protein powder and berries on top

2 eggs with veggies on whole wheat toast, english muffin or wrap

Protein bar with an apple or other piece of fruit

A smoothie made with protein powder and fruit (ex. 1/2 banana and berries)

Banana with nut butter on whole wheat toast or english muffin

Greek yogurt parfait topped with fruit and granola

Veggie burger on a whole wheat bun

Sweet potato with fish and veggies

Chicken with rice and veggies

*The amount depends on many factors – your workout type, duration, intensity, gender, body size and goals.*

What about fat?

Minimize fat, or save it for another time of day – while it’s a healthy part of your diet, it slows down the transit of carbs and proteins in your stomach (which slows down the refueling process). That doesn’t mean no avocado (or nut butters), just keep them to a minimum and prioritize the carbs and protein first.

Other questions? Don’t hesitate to ask! I love answering. Leave a comment or tweet me @meginspirefit.

The Complete Guide to Workout Nutrition:

-Courtesy of Greatist.com

Other Recommended Reads:

All About Post-Workout Nutrition – Precision Nutrition

Post-Workout Nutrition Explained – Precision Nutrition

Post-Exercise Recovery for Athletes – Today’s Dietitian

Real World Advice for Post-Workout Nutrition – Breaking Muscle