Gain Muscle while You Sleep: Benefits of Eating Casein before Bed

How does casein stack up to whey protein and carbs as bedtime snacks?

By Michael Ormsbee, PhDFlorida State University
Edited by Kate Findley and proofread by Angela Shoemaker, Wondrium Daily

Recent research has defied the conventional wisdom that eating at night automatically leads to weight gain. In fact, the right snacks can even lead to muscle growth. Professor Ormsbee explains.

Man drinking protein shake late at night
Studies show that bedtime snacks of casein protein contribute to muscles growth overnight. Photo By Dusan Petkovic / Shutterstock

Bedtime Casein Studies

Research conducted by Professor Luc Van Loon in the Netherlands revealed that active young men who consumed casein protein drinks before going to bed experienced greater overnight muscle protein synthesis than those who did not. Until this point, though, the studies had not been long enough to show whether the increase in muscle protein synthesis would actually lead to more muscle mass or better body composition, though it looked promising. 

Thus, a follow–up study from Professor Van Loon’s group examined whether acute changes in muscle protein synthesis could translate to changes in muscle size and strength with long-term daily protein intake before bed combined with resistance training. They had all the research subjects complete resistance exercise for 12 weeks. 

At the same time, they gave one group a protein and carbohydrate drink made of about 28 grams (g) of casein and 15 g of carbohydrates every night before sleep. The other group got a no-calorie placebo. 

During the 12-week training, the group consuming the protein and carbohydrate drink appeared to have greater increases in muscle fiber size and maximal strength than the group getting no-calories, protein, or carbohydrates before bed. 

This study was able to show true improvements in body composition when protein was consumed at night during a 12-week resistance exercise program. We must consider that protein intake was not matched between groups, but this does show that specifically eating protein at night before bed can increase muscle mass in the long-term.

Comparing Casein to Carbs

Now that we know casein protein before bed is beneficial for muscle growth, you might be wondering if there are any other benefits from consuming casein at night. If so, how do these benefits compare to whey protein and even carbohydrates? 

“Fortunately, work from my lab answers a few of these questions,” Professor Ormsbee said. “We found that providing casein, whey, or carbohydrates within 30 minutes of going to bed led to greater resting energy expenditure—so burning more calories—in physically active men the next morning compared to a lower resting energy expenditure when the men were given a placebo at night before bed.” 

They also found that burning fat was better when fit young men drank either a placebo or a casein protein shake compared to when they were given whey protein or carbohydrates. This shows that the subjects who drank a placebo, which had no calories, and drinking about 150 calories of casein protein both responded with a nice fat oxidation or fat-burning response—a better response than drinking whey protein or carbohydrates.

Taken together, this information reveals that if you are an active individual or athlete, consuming something before bed is better than going to bed on an empty stomach if you want to maximize your calorie burning potential. It also suggests that casein may be better than whey, as casein seems to increase muscle growth overnight and may promote a greater fat utilization. 

Bedtime Protein for Obese Individuals

Therefore, drinking small amounts of protein before bed seems to be beneficial for active people, but what about for overweight and obese people? The main reason people avoid nighttime eating is because they were told that it would make us store calories rather than burn them—that is, gain fat. However, is this the case when you eat specifically after dinner and before sleep, and you eat only a small portion?

To answer this, researchers provided small, low-calorie protein snacks and carbohydrate snacks in the form of cereal and milk to overweight and obese people 90 minutes after dinner. This was opposed to the typical high-calorie, high-fat meals that these people were used to eating at night. 

They did this every day for four weeks straight. What they found was that the people who were compliant and ate the cereal at night before sleep, which was about 130 calories of food, ended up lowering the total number of calories that they ate all day long on average over the four-week study. This led them to actually lose body weight.

“My guess is that just knowing that you are allowed to eat again later on in the evening might stop you from taking bigger servings or going up for seconds at your other meals,” Professor Ormsbee said. “Still, this is the only study to see nighttime feeding in a positive light for people who were not active or fit.”

This article was edited by Kate Findley, Writer for Wondrium Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for Wondrium Daily.
Dr. Ormsbee is an Associate Professor in the Department of Nutrition, Food, and Exercise Sciences and Interim Director of the Institute of Sports Sciences and Medicine in the College of Human Sciences at Florida State University.

Michael Ormsbee is an Associate Professor in the Department of Nutrition, Food, and Exercise Sciences and Interim Director of the Institute of Sports Sciences and Medicine in the College of Human Sciences at Florida State University. He received his MS in Exercise Physiology from South Dakota State University and his PhD in Bioenergetics from East Carolina University.