Leg Day Observer

What time should you eat to gain muscle? The complex science, explained

Does meal timing affect muscle growth? Here’s what you need to know.

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There’s an old legend that if you skip the protein shake right after lifting, you might as well not work out at all. Your muscles desperately need protein immediately after a lift (the story goes) or they’ll literally shrink.

The post-workout shake — fake food designed to give you the protein you need right after a lift — is more or less the foundation of the supplement industry. It’s also a perfect example of how confusing nutrient timing can be for lifting. Is it better to eat something that’s not exactly food right away, or hold off for a bit? And when should you eat during the rest of the day?

Though most lifters (and coaches) agree about the importance of post-workout shakes and meals after lifting, timing food over the rest of the day is a little more complicated. Whereas lifters once stuck to the time-honored bodybuilding meal-timing protocol (grazing on six small ones a day, each with some protein), many have switched over to intermittent fasting, skipping food for more than a day at a time.

Surprisingly, the results wrought out of each diet don’t seem that different. It’s not as if lifters who intermittently fast are the only ones winning competitions — or losing them. Diets and meal timing make up just one factor contributing to a lifter’s success. And because the when of eating seems to have such hazy results, it’s worth asking how much of a difference nutrient timing actually makes and whether it does so at all.

What science says about weight lifting and meal timing

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The conclusions coming out of scientific studies covering nutrient timing are mixed.

  • A 2006 study found some benefits from a protein shake with carbs taken before and after a workout.
  • A 2014 paper published in the Journal of the International Society of Sports Nutrition notes that straying from the traditional bodybuilding plan of six small meals a day, “appears to have little effect on fat loss or muscle retention,” and that keto diets — no carbs — might only work because of a calorie deficit.
  • One study, from 2013, found that protein, taken after a workout, didn’t appear to affect strength or muscle size; another, published in Nutrients.
  • A 2020 study looking at pre-, intra- and post-workout nutrition, arrives at the inverse: athletes see no disadvantage from clustering food around a workout.

The studies concede an advantage to getting some protein around a workout and are vague about the extent to which other changes affect a lifter’s results. They also all take macronutrients, and calories as a given, which is the key to understanding how nutrient timing works.

How Meal Timing Fits Into Diet and weight lifting

Diets for lifters generally try to shed as much fat as possible while maintaining maximum muscle.

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Ultimately, nutrient timing can be split between workout adjacency and the rest of the day, but the same dietary frameworks apply to just about everyone. All lifters eat at a caloric deficit, maintenance, or in excess, based on how much energy they need to get through the day and their workouts. Someone who burns lots of energy needs lots of calories; someone who doesn’t burn very much will find it harder to lose weight.

Diets for lifters generally try to shed as much fat as possible while maintaining maximum muscle. They’re called cuts and hover around a daily 10 percent calorie deficit. (Bulking lifters usually add 10 percent to their maintenance number.) The rough math is that by eating just a bit less than you should, you slowly lose some fat and hang onto your muscle.

Since each macronutrient (protein, carbohydrate, and fat) has a caloric equivalent, macros get counted instead of calories. The three keep the body functioning properly. Protein maintains and grows muscle cells. Upping protein during a cut — situations in which the body isn’t getting as many calories as it should — ensures minimal muscle is lost. But because of the stress on the body, it’s best to keep cuts to 12 or so weeks at the most.

Meal timing, diet, and weight loss

The best nutritional timing protocol seems to be the one that’s easiest to stick to: the one that feels least like a diet.


Meal-timing protocols like intermittent fasting and bodybuilding ultimately work as ways to make cuts easier and, in many ways, have more things in common than differences. Both recommend slower-digesting proteins (like casein) at the end of the day or eating window. Both hew to a calorie count, and try to stave away catabolism as much as possible. Both are different ways to stay full and stay on the diet. IF clusters calories to a few hours a day, which means bigger, more filling meals. The bodybuilding protocol ensures only a few hours lapse between one meal to the next.

To be sure, each purports benefits at the cellular level: spacing out food, bodybuilder style, is the closest way to ensure a steady amino acid drip into muscle cells; which is thought to be the surest way to avoid catabolism. IF boosts the body’s leucine production, by starving it, which has been found to lead to muscle growth.

Weighing in or competing requires lifters to have minimum fat and maximum muscle, and so it’s likely plenty of experienced lifters have tried one diet or the other: if one doesn’t work, maybe the other one will. But leaving aside the body image issues these diets may perpetuate, the best nutritional timing protocol seems to be the one that’s easiest to stick to: the one that feels least like a diet.

Meal Timing and “Aesthetics”

Nutrient timing is often framed as aesthetic: pre- and post-workout meals are, in diet books and discussions online, restricted and maximized to get the maximum amount of calories a lifter needs while not creating way too much hunger lately.

It’s not really about eating a bit more than you need and feeling good after a lift. Almost every piece written on cutting, to their writers’ credit, concedes some loss in strength and endurance. Muscle mass is, on a cut, a thing that at best gets maintained — not so much grown. Bulking lifters and athletes in maintenance have a little more leeway to fuel their workouts, and not work within a restriction.

Meal Timing vs. Intermittent Fasting: One small advantage

Nutrient timing, in this sense, is an elite protocol.

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Renaissance Periodization, a diet program created by PhDs who lift and compete, ranks nutrient timing as the third biggest factor for getting a lifter in shape, after calorie balance and then macros, and ahead of food quality and supplements. Their meal timing prescriptions are pretty granular: a bodybuilding-type small meal-plan scenario, with high-carb, high protein post-workout meals that hover at 40% of a lifter’s daily calorie requirement. Nailing all those numbers, and finding what food to eat seems to require a subscription or book unless a lifter has an expert-level understanding of counting macros.

Nutrient timing, in this sense, is an elite protocol: a way for competitive athletes, who all seem to have diet and training locked in, to reach loftier goals that their peers are also after. Optimizing meal times is hazy, and the science seems to change every year; dialing in feeding times might allow for more muscle production at the cellular level, or more energy around a workout; tweaking when you eat, so long as your macros are nailed, can only have benefits.

Renaissance Periodization mostly concurs, with their website estimating nutrient timing’s benefits at around 10% of a diet’s success. It’s the difference between an A grade and a B, and while the numbers RP are touting are hard to suss out, the results on their website — people nailing their diets, and putting on muscle — are in many ways easier to understand than the hedged conclusions reached in dense scientific studies.

Ultimately, the confusion around nutrition timing comes from advanced protocols leaking into workaday lifting: most of us should just hit our calories and macros every day for a while, and see where that takes us. But there’s no downside to tweaking a mealtime and adjusting ratios if you’re after something higher level. Once the overall picture is nailed, we can begin focusing on the details.

LEG DAY OBSERVER is an exploratory look at fitness, the companion to GQ.com’s Snake America vintage column, and a home for all things Leg Day. Due to the complicated nature of the human body, these columns are meant to be taken as introductory prompts for further research and not as directives. Read past editions of Leg Day Observer for more thoughtful approaches to lifting and eating.

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