Why Most Endurance Athletes Don’t Usually Need to Eat After Workouts

 

Most endurance athletes are obsessive about eating after workouts, and you can’t blame them. Almost every magazine, book, blog, web article, coach, and expert nutritionist says that you should eat as soon as possible after endurance exercise.^1-17

Some go so far as to say that “you are defeating the whole purpose of working out if you do not have a post-workout meal planned.”

The same article states that “in order to recover properly and start preparing yourself for your next workout, you absolutely need a post-workout recovery meal.”

Others claim that if you don’t eat at least 30 minutes after your workout, “…you’re certain to delay recovery… Don’t delay. Begin fueling as soon as possible after your cool down.”⁴*

Even if you ate before and during the workout, most sources claim that you still need to eat immediately after training.^1,3-5,7,8

You’re told to eat after a workout even if you’re not hungry. In fact, many sources recommend purposely choosing liquid meals or supplements over real foods specifically because they’re less filling.^1,3-5

In some situations, post-workout nutrition is important. However, research shows that in most cases, eating immediately after endurance exercise is not likely to improve your recovery or performance.

Let’s see why endurance athletes place so much emphasis on post-workout nutrition.

The Science Behind the Post-Workout Recovery Window

After exercise, your muscles are more receptive to nutrients like carbohydrates and protein.^18-23 This effect declines the longer you wait after your workout.^24-30

Usually, it’s said that “you have a 30 minute window after a workout is over to replenish what your body depleted during the workout.” If you don’t consume carbs and/or protein during this “most critical phase of recovery,”⁴ the window closes, and you’ve compromised your recovery for the next several days (in theory).

It’s also claimed that over the long-term, eating soon after your workout will improve your performance and possibly reduce your risk of injuries, since your muscles are better able to adapt to your training.⁵

If you don’t eat carbs and protein at least 30-minutes (some claim <15 minutes) after a workout — you will, theoretically, suffer the following consequences:

• Your muscle glycogen levels won’t be high enough for you to perform well in your next workout.
• Your muscles will continue to break down after the workout and won’t recover as quickly.
• You won’t adapt as well to your training over the long-term, and your performance will suffer.
• Your immune function will remain depressed for longer after each workout, increasing your risk of infection.
• You may have a higher risk of injuries and overtraining from lack of recovery.

The idea of the post-workout “recovery window,” or “glycogen window,” is considered by most to be the cutting-edge of nutrition science. Some articles call it “one of the most important sports nutrition discoveries in recent years,” and state that it is a “…fact that timing is essential with regard to post-exercise nutrition…”

Some authors even claim that the recovery process “…can’t even begin until you eat or drink. So the sooner you eat and drink, the faster and more thoroughly you will recover and the sooner you will be ready to perform well in a subsequent workout.”⁵

Let’s look at the evidence behind these five claims.

1. Maximizing Glycogen Resynthesis After Endurance Exercise is Usually Not Necessary

Glycogen is the main fuel source during moderate to high intensity exercise,^31-33 and high glycogen levels are important for optimal performance.^27,34-40 However, there’s not much evidence that it’s always necessary to eat carbs immediately post-workout to maximize glycogen storage.

Glycogen levels will return to normal within about eight hours if you eat on a normal meal schedule — without immediate post-workout nutrition.^25,41 If you train once daily, then you’ll have plenty of time to restock glycogen levels before your next session without eating in the post-workout “glycogen window.”

As long as you consume enough total calories and carbs before the next day’s workout, your glycogen levels will generally be just as high if you eat immediately after exercise or several hours later.

As Dr. Louise Burke writes in a 2011 review on using carbohydrates to maximize performance, “during longer recovery periods (24 h) when adequate energy and carbohydrate is consumed, the types, pattern, and timing of carbohydrate-rich meals and snacks can be chosen according to what is practical and enjoyable,” rather than rushing to eat a special recovery meal within the 30-minute glycogen window.²⁷

You also need to train for about 1-2 hours at a moderate to high intensity to completely deplete a muscle’s glycogen.^42-47 Most recreational endurance athletes (at least runners) don’t train multiple times per day.^48-50 If they do, one of the workouts is often much easier, which would make maximizing glycogen levels far less important for that session.

Furthermore, endurance athletes often alternate between upper and lower body muscle groups if they train on the same day. A triathlete might do a swim in the morning and a run in the afternoon, or a bike ride in the morning and lift weights in the evening. While there is still some overlap between running and swimming, maximizing glycogen resynthesis will still be less important since you’re using different muscle groups.

If you eat before or during a workout, you’ll also use less muscle glycogen during exercise.^51-53 The food you ate before and/or during your workout will still be digesting after you finish training, supplying carbs for glycogen resynthesis. This further reduces the need to maximize glycogen levels with immediate post-workout nutrition, since you’re pre- or peri- workout meal is also acting as a post-workout meal.⁵⁴

2. Post-Workout Nutrition is Not Essential to Stop Muscle Protein Breakdown

Muscle damage often occurs during endurance exercise and continues during the post-workout period.^55,56 Eating protein and carbs immediately post-workout is supposed “to limit post-workout muscle damage and accelerate the repair process…”⁵

In theory, the protein is supposed to serve as the “raw material” for growth and repair, and the carbs are supposed to help increase insulin levels, “…which reduces muscle protein breakdown…”⁵

However, there’s little evidence that eating protein and carbs immediately post-workout, compared to other times, reduces muscle damage or stops muscle protein breakdown.

Endurance athletes usually eat a few hours before training. They also usually eat during the workout. As a result, they still are generally digesting a fair number of calories, carbs, and protein. Consuming extra protein and/or carbs after the workout versus before and/or during, is not going to further reduce muscle breakdown or increase protein synthesis compared to eating a normal meal a few hours later.

A normal mixed meal takes about 4-6 hours to digest. During this time, it’s still releasing glucose and amino acids into the bloodstream. A normal size mixed meal keeps insulin levels high enough to maximize protein synthesis and minimize protein breakdown for about the same time period.⁵⁷

3. Eating Post-Workout Usually Won’t Affect Your Long-Term Performance

In theory, eating immediately after your workouts will help you recover faster. It’s supposed to help you handle more training and adapt better to your current training load, which should improve your performance over time.

However, as we’ve already covered, it’s usually not necessary for most endurance athletes to maximize glycogen storage after workouts. Protein synthesis will already be maximized, and protein breakdown minimized, by eating protein and carbs before and/or during the workout.

Unless you’re training the same muscle groups to glycogen depletion, within eight hours, multiple times a day; or training fasted with low starting muscle glycogen, there’s little evidence consuming immediate post-workout nutrition is going to improve your performance in later workouts or over time.

There’s also some evidence that doing small amounts of fasted training and/or exercise with low muscle glycogen may be beneficial in some cases,^27,36,58,59 but we’ll cover that in another article.

4. Eating Post-Workout Has Not Been Proven to Help You Avoid Getting Sick

After a workout, immune function tends to be depressed for about 3-72 hours.⁶⁰

Eating carbs before, during, and after exercise can reduce the rise in inflammatory cytokines and stress hormones like cortisol. It can also help prevent some negative changes in immune function caused by exercise, while others are unaffected.^{61-64 65-69}

This is often interpreted as proof that post-workout nutrition will drastically reduce your risk of getting sick.

However, it’s not clear if these transient changes in immune function translate into an increased risk of infection.^62,68,70

One of the few tests that is more closely linked to an increased risk of infection is a lower salivary immunoglobulin A  (IgA) level.^71-80 Interestingly, consuming carbs around exercise “… has little effect on decrements in salivary IgA output…” While eating around exercise can generally help reduce the drop in the number of circulating immune cells, it has almost no effect on “… T cell and natural killer cell function [emphasis mine].”⁶¹

Eating post workout, as opposed to before or during, has also never been proven to be better for bolstering immune function or reducing illness.

Some researchers have also suggested that reducing the inflammatory response to exercise may not always be a good thing. Some cytokines like IL-6 play a role in the adaptation to training. Going out of your way to reduce them might limit some of the positive responses to exercise such as improved immune function over time.⁸⁰

At this point, eating immediately post-workout has not been proven to improve immune function or reduce the risk of getting sick compared to eating at other times. Given that most endurance athletes eat before and/or during training, it seems unlikely that consuming extra food immediately afterward is going to be of much benefit.

5. Eating Inside the Post-Workout “Recovery Window” Probably Won’t Reduce Your Risk of Injuries or Overtraining

Injuries and overtraining are generally caused by a long-term imbalance between recovery and training.^81-84

As we’ve already covered, immediate post-workout nutrition is generally not going to increase your rate of recovery. There’s also little evidence it will enhance  your immune function, which leaves little reason to believe it will protect you from injuries or overtraining in most cases.

Why Most Endurance Athletes Don’t Need to Eat After Workouts

Despite the fixation on eating immediately after endurance exercise, there’s little evidence it’s usually necessary for most athletes.

No matter how much you train, the total amount of calories, carbs, protein, and fat you eat by the end of the day is far more important than when you eat.

Unless you’re doing multiple glycogen depleting workouts within about eight hours with the same muscle group, or training fasted with low starting muscle glycogen, immediate post-workout nutrition is rarely going to be better than eating before, during, or several hours after your workout.

This doesn’t mean you can’t or shouldn’t eat post-workout, but there’s no need to rush in most cases. You can be far more flexible about when you eat and still perform just as well as your friends who have a glovebox full of recovery bars, bring tupperware meals to every workout, and live off of recovery shakes.

In later articles, we’ll explore how to decide when it is best to eat post-workout, and if so, how much, when, and what to eat.

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* Amusingly, this is a quote from The Paleo Diet for Athletes, which goes on to recommend “liquid meals” and “commercially produced recovery drinks” on the next page. This is, of course, how cavemen recovered from a hunt.

 

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