Despite all the confusion surrounding pre and post-workout nutrition, what you should consume comes down to common sense, more than anything else.
To break it down mechanistically, carbohydrates are the primary energy source for any activity you would be doing, and often lead to better performance in training. Protein is the main substrate for building new muscle tissue. It makes logical sense to have these in your circulation at the time of training, and this can be accomplished some different ways:
- A large meal 4-6 hours before a training session could give you plenty of circulating glucose and protein, and replenish your glycogen stores enough to fuel your training.
- A shake consisting of about 25 grams of protein and 30-50 grams of carbs 1-2 hours before a session will have a similar effect. The reason for the shorter interval is because unlike normal solid-food meals, shakes consumed on an otherwise empty stomach are assimilated much faster, often within a couple of hours. An exception to this would be casein protein products. Casein has a similar digestion time to that of whole-food sources, sometimes even longer.
The Anabolic Window
The same applies post-workout. Even though it’s something of a joke these days, scientific literature has shown that an “anabolic window” exists in some capacity. However, it’s not the “chug a shake within 20 minutes of my last rep or all my precious gains will spontaneously combust” kind. It varies depending on training experience.
In a nutshell, there is a period of 1-3 days that untrained individual/beginners have improved nutrient partitioning to muscles. This could be advantageous for growth. This period is cut down to 6-24 hours for trained athletes. One can safely assume that for extremely advanced athletes (national-level/pro-card-holding strength/physique competitors) this time frame would be cut down to the range of 2-4 hours.
What About Fasted Training?
Some individuals experience better training performance when fasted. This seems to be particularly prevalent in intermittent fasters who have a large bolus of food at night before bed and train in the mornings. This would spur the logical explanation that a large meal right before bed sufficiently replenishes glycogen enough to ensure a quality training session the next morning.
Supporting this hypothesis would also be the fact that, unless you are a Crossfitter or team/field-sport athlete, most resistance training sessions are relatively undemanding as far as energy stores go. You are very unlikely to completely tap out your body’s glucose reservoirs unless you are doing some really high-volume stuff. This is one case however, where I would recommend intra-workout nutrition (e.g. electrolytes with a scoop of BCAAs mixed in), and having a little more haste with your post-workout meal. It’s safe to assume that prolonged complete fasting, along with a highly energy-intensive training session, has the potential for some significant detrimental effects if not properly accounted for.
Use Common Sense
As long as you eat something within +/- 6 hours of when you train (which, honestly, the enormous majority of people will end up doing as a part of normal life), you’ll be more than set. If you’re an advanced athlete that really wants to stay on top of things, make sure to get in a bolus of protein and carbs after you get home from the gym.
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