Does Eating During the ‘Anabolic Window’ Really Help You Build More Muscle?

We’ve all seen it: That person at the gym with their shaker bottle, taking a swig immediately post-workout. Or maybe you’ve even gotten in the habit of crushing a couple hard-boiled eggs after your HIIT class. At the very least, you probably have a vague inkling that you should be eating something shortly after a workout—preferably with protein and carbs—in order to maximize your results.

For years, the immediate post-exercise period has been considered an anabolic “window of opportunity,” in which muscles are able to more efficiently suck up and utilize nutrients than other periods—and this, in turn, is said to support muscle strength, growth, and recovery. But what if you wait a few hours, or until your next meal, to nosh on something? Are you really missing out? 

Below, we dive into the latest science on post-workout nutrient timing, whether the anabolic window is real, and the nutrition advice from sports dietitians that you should actually focus on to maximize results. 

What Is the Anabolic Window?

The “anabolic window” is a term often used to describe the short period of time—within 30-60 minutes—following a workout in which muscles are in an “anabolic” or muscle-building state. It’s commonly said that you can optimize muscular gains and recovery by having a meal, snack, or shake with protein and carbohydrates during this period, and that waiting longer diminishes these benefits. 

“The theory is that muscles that just worked hard during a workout are more primed to use protein and carbs to rebuild themselves in the immediate hour post workout than during the rest of the day,” says Holley Samuel, RD, a sports dietitian ​​and founder of Holley Fueled Nutrition. The rationale for optimizing nutrition during this short anabolic window typically comes down to two things: 

But, while the processes described above do occur, the timing of nutrient intake isn’t nearly as critical as once thought. “While we originally thought fueling during the anabolic window would make or break stimulating MPS and recovery, we are seeing now in research that these processes can be stimulated effectively for many hours post workout,” says Samuel. In other words, the popularly touted 30-60 minute post-workout anabolic window is somewhat of an outdated range. 

How Long Is the Anabolic Window?

Research now suggests that muscles may remain in an anabolic state up to 24 hours following a workout. Of course, this anabolic effect diminishes with time, so if your goal is to optimize muscle gains, you don’t want to wait quite that long to eat a balanced meal: Per the International Society of Sports Nutrition (ISSN), the greatest adaptations to exercise occur when protein is ingested within two hours following a workout. 

Unless you’re an athlete or doing twice-a-day workouts, experts like sports dietitian Heather Mangieri, RDN, say there’s also no need to eat carbs immediately post-workout to replenish glycogen stores. The takeaway: In most cases, “if an individual finishes a workout, and plans to eat a well-balanced meal in the next couple of hours, their muscles will still be sensitive to the meal consumed,” says Mandy Tyler, RD, sports dietitian for the San Antonio Spurs.

There is, however, a common exception that might warrant quicker post-workout nutrition: Working out in a fasted state—say, first thing in the morning, or when it’s been 4-6 hours since your last meal. “Eating within an hour of finishing training may be more beneficial for someone training in a fasted state than someone training an hour after lunch,” says Dana Horton, RD, a sports dietitian at Eleat Sports Nutrition. With fasted workouts, there are fewer circulating amino acids to support MPS and your body burns through its glycogen stores much quicker. On the other hand, if you’ve eaten a meal with protein and carbs within approximately three hours prior to your workout, it can still enhance MPS in the immediate post-workout period. Per the authors of a 2018 research review: “The closer the proximity of the meal to the training bout, the less the need for immediate post-workout protein intake; if training fasted, expeditious refueling with high-quality protein is beneficial to enhance muscular adaptations.”

A Better Approach to Fueling for Muscle Gains & Recovery

Much more beneficial than fixating on post-workout meal timing is ensuring that your total daily protein intake is sufficient. “Optimal protein intake and distribution throughout the day as a whole is most important; and when that is accounted for, consuming protein immediately after a workout provides no additional benefit,” says Derek Lipton, RD, a sports dietitian and founder of Full Circle Sports Nutrition. This is something most researchers and sports nutrition experts tend to agree on.  

To optimize recovery and build lean muscle, active individuals should aim to consume 1.4–2 grams of protein per kilogram of body weight per day, per the ISSN. That’s 96-136 grams for a 150-pound person. Protein intake should also be distributed relatively evenly throughout the day to maximize muscle growth and strength: Aim for roughly 20-40 grams every 3-4 hours as a part of meals and snacks. “Spreading out your protein intake makes it easier to hit your daily protein goal, manage hunger, and consume a variety of other nutrients needed to support muscle growth,” says Horton. At the same time, you want to make sure you get enough total daily calories and carbs to meet your needs, too. According to Mangieri, this allows your body to prioritize using dietary protein for repairing and building muscle, and not just burning it for energy—which is why carbs are said to have a “protein-sparing” effect.

So, Who (If Anyone) Should Prioritize Eating Right After a Workout?

Aside from people who work out in a fasted state, most active individuals don’t need to eat during the traditional 30-60 minute anabolic window to maximize the muscle-enhancing effects of a workout. As mentioned, within a couple hours should be just fine. But there’s also nothing wrong with eating shortly after a workout, and there are some scenarios where it may be extra helpful. We asked registered dietitians who are board certified specialists in sports dietetics to describe the people and situations that might warrant eating ASAP. Here’s what they had to say:

Bottom line: Aim to eat shortly after training if you are exercising in a fasted state, trying to gain weight, trying to stabilize cravings and energy, doing twice-a-day workouts, or if your activities include things like exhaustive strength-training sessions, running hard for 60-plus minutes, training for a marathon, or training for a century ride (a bicycle ride of 100 miles)—or simply if you’re hungry and feel like eating. 

Tips for Eating During the Anabolic Window (& Post-Exercise in General)

Whether you eat immediately after a workout or within a couple hours, advice for fueling is generally the same: An ideal post-workout meal or snack should include “carbohydrates to replenish energy stores, protein to build and repair muscle mass, fluids to replenish losses from sweat, and antioxidant-rich foods to help reduce inflammation,” says Horton. And, while fat isn’t quite as crucial after a workout as protein and carbs, you want a bit of that, too, as it promotes satiety and helps you absorb fat-soluble vitamins. 

If that sounds pretty basic, it’s because it is. “There's really no need to get complicated with post-workout nutrition,” says Lipton, adding that for most people it’s totally fine to stick to your typical meals and snacks, as long as they’re well balanced with protein, carbs, fats, fruits, and vegetables. 

Here are some dietitian-approved examples of post-workout meals and snacks:

Of course, if your workouts are on the more intense side, or if you’re an athlete or in training for an event, you may need to be a bit more mindful about numbers. “Typically 20-40 grams of protein and 30-90 grams of carbs is ideal,” says Samuel. “These are wide ranges, so it depends on the person, the workout, and their goals to get more specific.” For example, a bout of intense resistance training (which is harder on your muscles) may require protein on the higher end of this range, while a longer endurance workout (which burns through more glycogen) may require carbs on the higher end of this range.  

For most people, though, you can aim for a mix of macronutrients from nutritious foods, then tune into how your body feels and performs during future workouts—and then make adjustments as needed. 

The Takeaway

The commonly touted 30-60 minute anabolic window is an outdated concept—and fueling within this window will not make or break future muscle gains or workout performance. Instead, current research suggests muscles remain in an anabolic state for up to a day after a workout, and that eating a meal or snack containing protein and carbohydrates within two hours may yield the most beneficial results. Rather than fixating on nutrient timing, however, most experts say efforts are better spent ensuring that you consume adequate total daily protein and distribute your intake evenly throughout the day, along with getting sufficient calories and carbohydrates. That said, eating shortly after a workout can still be beneficial in a range of different situations outlined above, or if it better fits your schedule. 

This content is for informational and educational purposes only and does not constitute individualized advice. It is not intended to replace professional medical evaluation, diagnosis, or treatment. Seek the advice of your physician for questions you may have regarding your health or a medical condition. If you are having a medical emergency, call your physician or 911 immediately.