Many sports nutrition resources will tell you that there’s a “special window” after a workout in which you should refuel immediately, usually it’s a pretty small window, like 20-60 minutes. Why is there this window? Reasons may include aiding in protein synthesis, preventing muscle breakdown (catabolism), restoring glycogen, aiding in muscle repair and recovery, and so on. While I’m not arguing those benefits nor an athlete’s need to fuel appropriately for their training, that “special window” for refueling may not be as important or specific as we’ve been told.

“The importance–and even the existence–of a post-exercise ‘window’ can vary according to a number of factors (1).” In other words, there are times when it’s perfectly ok to wait more than 1-2 hours to refuel after a training session; meanwhile, there are cases in which refueling soon after your workout makes a lot of sense. It depends, and there is research to support both sides. This article points out some interesting facts and research that will help you determine your immediate refueling needs, while dispelling some myths.

Starting with this: In a large portion, if not majority, of research done on this subject, the studies that shows benefit to post-exercise fueling usually had the subjects fasted or in semi-starves state before exercise, thus why the post-exercise re-fuel window benefits are so great. That’s HUGE! In this case, refueling after a fasted workout becomes more important and beneficial. but sometimes we don’t get the memo that they were fasted and all we are told is “eat within 30 minutes or else!” (The takeaway here is that when reading a study’s conclusions make sure to also read the methods and study design to get the whole story—that pretty much goes for all research.)

Determine your post-workout fueling needs:

  • Six rules
    • If you ate something before working out (even as much as 2 hours before), it wasn’t a tough workout or race, and you just aren’t hungry after, don’t worry about eating right away. There’s no crucial need to fuel within 20-60 minutes after training. You’ll be fine.
    • If you were fasted pre-exercise, eat after. Sooner the better.
    • If you have another workout later in the same day, eat after your first workout (even if you ate something prior).
    • If you’re looking to add muscle mass and are in a strength training program, you need to stay anabolic so eat often, eat after exercise and eat/refuel even if you’re not super hungry.
    • If you’re recovering from adrenal fatigue or another health issue (e.g. hypothyroidism, etc.), you should be eating every ~3 hours and maintaining stable blood sugar, so take that into account for your exercise fueling needs.
    • Amino acid capsules are always a good idea, whether you will be eating or not. Pre-exercise amino acid supplementation is often seen as more beneficial than post-exercise, but both help. (PerfectAmino or essential AAs/BCAAs of choice).
  • Protein matters, a lot:
    • One study says taking in 0.5 g protein per kg LBM both pre and post-exercise is a “fail-safe” general guideline (1). This is essential for resistance training and staying anabolic, but it certainly applies to endurance training too.
    • Post-exercise ingestion (immediately to 2-h post) of high-quality protein sources stimulates robust increases in muscle protein synthesis (2).
    • If you’re not hungry, have your amino acids, mainly the branch-chained amino acids (PerfectAmino).
    • You don’t need more than 30-40 grams of protein per feeding; 20 grams usually adequate for athletes to get desired results (and making sure you’re getting in 1.4-2.0 g protein per kg bodyweight a day if training).
    • Protein synthesis post workout can last 24-48 hours, but you don’t necessarily want to wait 12-24 hours. Eating 1-3 hours post workout is beneficial, as is having even more protein before bed.
    • For something quick-acting, go for a protein drink. I like Vital Proteins products, and if you don’t do dairy get their Collagen Peptides.
  • Carb it up if:
    • If you trained fasted or it had been a while since your last meal (i.e. more than 3-6 hours), you should plan on a snack or meal after the workout, protein included too. The harder the workout (volume and/or intensity) the more important this gets.
    • If you know your workout will be a glycogen-depleting one (big day, race day, etc.), eating soon after will better support glycogen synthesis. Include protein too. Within 1 hour is fine; within 2 hours still beneficial.
  • Carbs vs. protein:
    • Essential amino acids with carbohydrates stimulate muscle protein anabolism by increasing muscle protein synthesis when ingested 1 or 3 h after resistance exercise (3).
    • “Post-exercise ingestion (immediately to 3 h post) of amino acids, primarily essential amino acids, has been shown to stimulate robust increases in muscle protein synthesis, while the addition of CHO may stimulate even greater levels of protein synthesis. Additionally, pre-exercise consumption of a CHO + PRO supplement may result in peak levels of protein synthesis (4).”
    • That said, studies show mixed results on whether protein or carbs are king. Some say the carb-protein mix is the holy grail while other studies say protein alone does the trick and the addition of carb makes no difference. I say, it depends on your workout. You don’t need to avoid either macro—even if you’re a low-carb athlete there still a time and place for carbs. Meanwhile, if your a vegan or vegetarian athlete finding a high-quality protein source is essential.
  • Other:
    • Athletes who are fat-adapted (i.e. metabolically efficient) may not burn through glycogen as quickly due to their ability to burn fat for fuel even at higher intensities, but you also don’t want to fall into a trap of being in a chronic energy deficit or constant hypocaloric state when in training, so you still need to eat when it makes sense. Low-carb fat-adaptation does NOT mean you can get away with a low-calorie diet if you’re a hard-training athlete!!!
    • “The addition of creatine (Cr) (0.1 g Cr/kg/day) to a CHO + PRO supplement may facilitate even greater adaptations to resistance training(4).”
    • It’s perfectly fine to have dietary fat in your refuel meal as well; fat won’t slow down your carb and protein absorption nor inhibit glycogen synthesis or muscle protein synthesis.