THE 30-MINUTE WINDOW
Post-Workout Meal Myths Part 1
It’s a concept that most people interested in fitness and nutrition have likely heard of: the post-workout meal. This magical dish gains enough attention to seem more important than the workout itself, and we are supposed to gulp it down before the narrow “post-workout window” shuts on our fitness dreams. I will go over a quick breakdown of the science behind the theory, bust a few myths, and leave you with the important bits.
WHAT IS THE POST-WORKOUT WINDOW?
Any type of training primes your muscle cells to uptake nutrients. This applies more to anaerobic training (weightlifting) than to aerobic training (cardio), but to some extent for both. The mechanism for this has to do with a protein found in fat and striated muscle cells, glucose transporter GLUT4. This protein acts to let glucose, our body’s preferred fuel source, to enter fat and muscle cells from the bloodstream. Muscle contraction causes GLUT4 to move from inside cells to the surface, which means that for some time after a workout, our muscle cells are better equipped to uptake (absorb) glucose to store for later or use as fuel. Luckily, exercise doesn’t prime our fat cells to uptake glucose wherein it would be stored as fat!
Aside: This process can also be triggered by insulin, which is released when we eat, such that sugars are absorbed and do not remain in the bloodstream. Exercise also increases our cells’ responsiveness to insulin, so that the insulin more effectively binds to receptors which signal GLUT4 to come to the surface and help glucose diffuse into cells.
So, the post-workout window is the period of time beginning immediately after training, lasting until the increased GLUT4 activity returns to normal.
WHY A POST-WORKOUT MEAL?
The idea is that by feeding our muscles as soon as possible after training, this transport protein will be maximally active. Calories (especially carbohydrates and sugars) consumed soon after training should be absorbed by muscle cells to be used for energy and recovery, rather than absorbed by fat cells to be stored as fat. The post-workout meal is the precise ratio and types of carbs and proteins and fats to replenish your muscles, assist in recovery, but not cause fat storage. Because of the enhanced sensitivity to glucose, in theory, this is the best time of the day to consume simple carbs such as sugars.
WHY SO QUICKLY?
The post-workout window has been defined many times: 20 minutes, 30 minutes, one hour, two hours, 90 minutes…
Again, as some would have you believe, the only way to make sure your workout doesn’t go to waste would be to have that shake with you to gulp down before getting down off the equipment after your last set. This brings us to...
MYTH #1 - The post-workout window is narrow and urgent.
In reality, it has been proven many times that the overall amount and type of food we consume daily is much more important than the timing! So, relax, finish your workout, get home, and prepare a quick and easy-to-digest meal. Of course I recommend testing it out for yourself if you’re curious – spend a few weeks with a post-workout shake in the shower, and then a few weeks where you cool off and eat some food (using your teeth) when you’re ready. DO what works best for you, but don’t stress about it! The truth is that well-trained individuals are in a state of near-constant post-workout-type response to food, so eating your pasta 62 minutes after the gym won’t harm tomorrow’s squats.
So what is in the post-workout meal?
Stay tuned and we will discuss it in the next post. Spoiler: it is similar to our conclusion of part one – relax!
Until then, tell us about your gym habits in the comments below – do you bring Tupperware to the change room or eat from the comfort of your home after a good stretch and shower?
Peter is a travelling fitness junkie, always on the search for new opportunities, places, and optimal physical and mental health. He has an academic background in chemistry and environmental science, and a passion for music, creating, and exploring!