When Should You Drink a Protein Shake? The Answer Is Simpler Than You Think

Protein is one of the body's most important building blocks, but for most healthy people the total amount eaten over the day seems to matter more than the exact minute you drink your shake. Many experts suggest spreading protein across your meals and, for comfort, having your last shake a little while before bedtime.

You have probably seen it at the gym: someone gulping down a shake before they have even taken off their headphones, convinced that missing the so-called "anabolic window" means the whole workout was wasted. Here is some good news. When the International Society of Sports Nutrition (ISSN) reviewed the research for its official position stand on protein and exercise, the experts concluded that total daily protein intake appears to be the strongest factor for building and keeping muscle, while the precise timing likely plays a smaller role. So the real question is not "now or never?" but "am I getting enough, spread out sensibly?"

What Arnold Schwarzenegger learned after 60 years in the gym

Few people on the planet have spent more time around protein shakes than Arnold Schwarzenegger. The seven-time Mr. Olympia, who first walked into a gym in Graz, Austria, still drinks his favorite shake today. Yet in his Arnold's Pump Club newsletter he tells readers that protein powder is not necessary to be healthy or strong. If you do use one, he says, read the label carefully and choose products that have been independently tested, for example by Informed Sport or NSF Certified for Sport. His practical tip is to aim for roughly 20 to 40 grams of protein per meal and to get that protein from whatever sources suit you: poultry, fish, eggs, dairy, legumes, soy, or a shake.

That message also fits everyday life. Picture a busy nurse who finishes a night shift, grabs a coffee, and only realizes at 3 p.m. that she has barely eaten. For someone like her, a shake is not about big biceps. It is a quick way to fill a gap on a day when a proper meal simply does not happen.

How much protein do you actually need?

Protein needs differ from person to person. On days when we are more physically active, we need more protein. Proteins are the building blocks the body uses to repair and build itself: muscles, skin, hair, hormones and enzymes all depend on them. If these building blocks run short over a longer period, the body may start to struggle with recovery and with keeping its muscle mass.

A general guideline is that adults need about 0.8 grams of protein per kilogram of body weight per day. The European Food Safety Authority (EFSA) sets its reference value at 0.83 g/kg, which works out to about 58 grams a day for a 70 kg adult (more on this in our article Plant Proteins for a Longer Life). People who train regularly usually need more. The ISSN position stand suggests roughly 1.4 to 2.0 g/kg per day for most exercising individuals. That is why athletes and anyone who trains a lot often make sure they get enough protein throughout the day. It supports muscle recovery, and protein also tends to keep you feeling full for longer.

People who eat mostly plant-based foods sometimes find it harder to reach their target, because many plant foods contain less protein per serving. The solution is variety. Beans, lentils, tofu, nuts, seeds and whole grains can add up quickly, and chickpeas deserve a special mention (see A food that has more protein than an egg!).

Many people in Europe and North America already get enough protein from ordinary food. As a recent Nature feature points out, protein supplements are mainly useful for certain groups: people with high training loads, older adults with small appetites, or anyone who struggles to eat enough protein-rich meals.

Why protein shakes are so popular

Today's protein shakes are easy to prepare, so they suit people who spend a lot of time on the go. A scoop of powder, a shaker bottle, a little liquid, and you have 20 to 30 grams of protein in under a minute.

Keep an eye on what you add, though. Milk, nut butter, fruit, honey and oats are all nutritious, but they can turn a light shake into a full dessert. If you are watching your weight, count the extras too. Our article Hello, and Fattening: Foods that Sabotage Your Diet shows how quickly hidden calories can add up.

Before and after exercise: a simple rule of thumb

Some nutritionists and trainers use an easy-to-remember rule: before exercise, drink as many grams of protein as the number of minutes you plan to train (for example, 20 grams for a 20-minute session). After training, have roughly the same amount again. Research does not require such exact matching. The ISSN generally points to about 20 to 40 grams of high-quality protein per serving, eaten in the hours before and/or after training. As a simple habit, though, the rule is practical and keeps portions sensible.

For the post-workout snack, pay attention to adding some calcium and vitamin D. Together with protein and regular exercise, these nutrients help support healthy bones and muscles, which matters more and more with age, when the risk of osteoporosis and gradual muscle loss increases. You can read more about both nutrients in the fact sheets from the U.S. National Institutes of Health on calcium and on vitamin D, as well as at the International Osteoporosis Foundation.

In the past, this usually meant mixing protein powder with milk. Today, a popular alternative is Greek yogurt with two tablespoons of nuts. The yogurt provides protein and calcium, and the nuts add healthy fats, magnesium and a pleasant crunch. Vitamin D is harder to get from food, so on days with little sunshine, fortified dairy products, eggs or oily fish can help. Some people also take a supplement after talking to their doctor.

And what about bedtime?

Here the practical advice and the lab research send slightly different messages, so here are both.

The practical advice: many people find that a large, heavy drink right before lying down causes bloating, heartburn or a restless night. For them, finishing the last shake about two hours before sleep is a simple, comfortable rule. Good sleep is itself important for your figure, as explained in our article When you sleep too little, your belly grows.

The research angle: scientists at Maastricht University found that in young men who trained in the evening, slowly digested casein protein taken shortly before sleep was well absorbed overnight and supported muscle recovery (Medicine & Science in Sports & Exercise, 2012). A follow-up study in The Journal of Nutrition suggested this habit may add to training gains over several weeks. A systematic review in the Journal of Science and Medicine in Sport urges caution, however, since the evidence for older adults is still limited. In other words, a late protein snack such as cottage cheese or Greek yogurt is not harmful for most healthy people. If it sits heavily in your stomach, simply move it earlier.

Can you have too much of a good thing?

Yes. More is not always better. Very high protein intakes over long periods may put extra strain on the body, especially for people with existing kidney problems, and they often push aside fiber-rich foods such as vegetables, fruit and whole grains. You can read more in our article High-protein diets are dangerous for health. If you have a medical condition, are pregnant, or are unsure what amount is right for you, talk to your doctor or a registered dietitian before relying on supplements.

So: when is the right time for a protein shake?

Anytime that fits your day. For most healthy people, reaching your total daily protein target and spreading it over several meals matters more than the exact minute. Around workouts is a convenient moment, and if a late shake bothers your sleep or your stomach, just have your last one at least two hours before bedtime.