Do You Really Need to Eat Within 30 Minutes After Every Workout?

by Matt Fitzgerald
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Do You Really Need to Eat Within 30 Minutes After Every Workout?

Every once in awhile, sports nutrition researchers change their minds. When they do, a common practice that athletes thought was based on solid science may be exposed as a myth. One recent example is the practice of consuming salt tablets during races to prevent muscle cramps. Scientists now know that exercise-associated muscle cramps are not caused by the loss of electrolyte minerals in sweat, as they had believed since the 1930s. Rather, they are caused by an abnormal nervous system response to extreme fatigue in individual working muscles.

When a common sports nutrition practice, such as taking salt tablets during races (which may be beneficial for reasons other than preventing muscle cramps), is revealed to be baseless, athletes can’t help but turn a skeptical eye toward other practices. What will we learn next—that eating within 30 minutes after completing a workout does not, in fact, accelerate muscle recovery and improve performance in the next day’s workout?

Let’s take a closer look at the science behind immediate post-workout nutrition intake. When we do, we quickly discover that the 30-minute threshold is somewhat arbitrary. There are no studies showing that eating a snack, say, 25 minutes after exercise results in faster recovery than consuming the same snack 35 minutes after exercise. However, there is plenty of evidence that eating immediately after a workout is better than waiting a long time.

In 2001, for example, researchers at Vanderbilt University Medical Center in Nashville, Tenn., fed volunteers a snack containing 10 grams of protein, 8 grams of carbohydrates and 3 grams of fat either immediately or three hours after completing 60 minutes of moderate-intensity exercise. Two of the most important recovery processes are:

  • Replenishment of muscle glycogen fuel stores, which requires carbohydrates
  • Muscle repair, which requires protein

 

The researchers found that postexercise muscle glycogen synthesis proceeded 44% faster, and protein synthesis in the exercised muscles 300% faster, when the volunteers ate immediately after their workouts.

Other studies have proven that accelerated muscle refueling and repair translates into better performance in the next workout. In one such study, exercise physiologists at the University of Texas asked 10 cyclists to complete a 90-minute ride followed four hours later by a 40K time trial on three separate occasions. On one occasion, the cyclists were given chocolate milk (containing carbohydrates and protein) to drink immediately after and again two hours after the first ride. On a second occasion, they were given a drink containing carbs but no protein. And on a third occasion, they were given a noncaloric placebo. On average, the cyclists completed the time trial more than six minutes faster after consuming carbs and protein than they did after consuming carbs alone, and more than seven minutes faster than they did after consuming flavored water.

Of course, it’s not often that you’ll want to complete a 90-minute workout and an all-out time trial on the same day, but these results show that faster muscle recovery resulting from immediate post-workout nutrition intake has the practical benefit of enabling the muscles to perform better the next time they are challenged. This study also confirms that the ideal post-workout snack, meal or supplement contains both carbohydrates and protein.

The benefits of immediate post-workout nutrition intake don’t end here, though. It is well-known that the physiological processes through which the muscles recover from exercise overlap with the processes through which the body adapts to training. Based on this knowledge, the same research team that performed the study just described conducted a follow-up study in which they measured the effects of repeatedly consuming one of the same three beverages after daily workouts on changes in aerobic capacity (VO2 max) and body composition. After one month of training, the subjects receiving the carbohydrate-protein beverage were found to have made more than double the gains in aerobic capacity than the other two groups, while also gaining more muscle and losing more fat.

That’s right: Habitually consuming appropriate nutrition after workouts will not only allow you to recover faster and perform better in your next workout, but it will also make you fitter and leaner than if you did the same training without this habit.

Most of the research in this area has involved packaged products such as recovery beverages and chocolate milk. It is not necessary to use such products, however. Literally anything that contains carbs and protein will do the trick. Indeed, a news-making 2015 study done at the University of Montana found that fast food facilitated muscle recovery about as well as a commercial recovery beverage. A better choice for health reasons, though, would be a high-quality natural food with carbs and protein such as yogurt and fruit, a turkey sandwich or an omelet with cheese and vegetables.

Don’t fuss too much over the exact timing of your post-workout snacks or meals. Just make sure that eating is among the first things you do after you shower and change. Nor do you need to worry about the precise number of carbohydrates and protein calories you’re getting. What’s important is that you get something appropriate in your system soon enough to kick start the recovery process. Eating on a normal schedule for the rest of the day will finish the job. For reference, the subjects in the last study described in this article took in about 0.42 gram of carbs and 0.14 gram of protein (plus 0.08 gram of fat) for every pound they weighed in the first hour after exercise.

A final note: If you choose to get your post-workout calories from solid food, be sure to drink something, as well. Although less time-sensitive than muscle refueling and repair, hydration is also an important piece of the recovery puzzle. And sports scientists are unlikely to change their minds about that!

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