Some experts say that you should eat an early dinner and then not munch again until the next morning. It’s true that snacking on processed carbs and sugar before sleep won’t help your body composition and might, in fact, lead to weight – but what about protein?
If you weight train, you know how important protein, specifically amino acids, are for muscle repair and growth. If you train hard, you may need as much as twice the protein of a sedentary individual. Recommendations are that a sedentary person get around 0.8 grams of protein per kilogram of body weight. If you train intensely, as much as 1.6 grams of protein per kilogram of body weight might be appropriate. Regardless of how much protein you take in, the best way to get it is to spread it out over the day. Make sure each meal and snack has a source of lean protein.
Then there’s the issue of bedtime. Why WOULD you want to eat protein before hitting the sack? Your muscles recover and rebuild from a weight-training workout while you’re resting and sleeping. By supplying your body with amino acids prior to sleep, you ensure they have the building blocks they need to grow. Consuming protein also helps keep your body from entering a catabolic state where you break down your hard-earned muscle. During a peaceful slumber, when you’re not eating, muscle breakdown typically exceeds muscle protein synthesis. By supplying your body with protein, you can theoretically reduce muscle breakdown.
The question is whether this holds true in actual practice. If you eat protein before bedtime consistently will it help your muscles grow or become stronger? According to a study published in the Journal of Nutrition in 2015, the answer is “yes.”
Bedtime Protein for Muscle Growth?
In this study, researchers asked 44 healthy, young men to take part in a strength-training program for 12 weeks. One group received a supplement containing 28 grams of protein and 15 grams of carbohydrates prior to bedtime each evening. The other took a placebo that contained no protein or carbs. The type of protein in the supplement was part casein and part casein hydrolysate.
The results? Both groups experienced an increase in strength and muscle size – not surprising since they were strength training. However, gains in muscle strength and muscle size were greater in the group who consumed the protein supplement before going to sleep. What’s not clear is whether smaller doses of protein prior to bedtime would have a similar effect.
Casein vs. Whey
The protein researchers used in the supplement was casein and casein hydrolysate. It’s possible that another form of protein supplement, like whey or soy, may not offer the same benefits. Casein is a type of dairy protein abundant in foods like cottage cheese and Greek yogurt, one that causes a slow but sustained rise in amino acid levels in the bloodstream. That’s important since you want to keep your muscles supplied with amino acids throughout the night.
In contrast, whey protein is rapidly absorbed and causes a quick rise in the blood level of amino acids. However, blood amino acids fall more quickly after whey protein than casein. This makes whey protein ideal for getting amino acids to your muscles quickly right after a workout but not as effective at sustaining blood levels throughout the night. One advantage of whey over casein is whey contains more of the amino acid leucine, an amino acid most strongly linked with muscle protein synthesis. Leucine is one of the branched-chain amino acids that also includes valine and isovaline.
In fact, leucine may be THE most important amino acid for muscle protein synthesis. That’s because it activates mTOR, also known as mammalian target of rapamycin). mTOR acts like a “switch” that turns on the synthesis of new muscle proteins. Whey delivers a large hit of leucine to turn on the muscle-building machinery.
As you can see, casein and whey each has unique benefits – whey gives you more leucine while casein keeps amino acid levels higher in your blood stream for a longer period of time. Ideally, it would be nice to have the benefits of both. If you’re sleeping for 7 or 8 hours, a slow, sustained release of amino acids that’s longer lasting works best. Possibly the best approach is to get whey AND casein before bedtime. While you could get either of these forms of protein from food, you’d have to eat a fair amount of food and a significant number of calories. Is it practical to go to bed with a stomach full of food, even if it is high in protein?
In this case, a protein supplement shake is a convenient alternative and the best type of protein supplement might be a blend of whey and casein. A blend gives you the benefit of more leucine (from whey) along with the staying power of casein. More companies are starting to make these combinations available due to popular demand. If you use a protein supplement, buy from a reputable manufacturer. Consumer Lab found that some protein supplements are contaminated with heavy metals and other impurities. Some also lacked the ingredients listed on the label. In all, just over 30% of the samples they tested failed quality control.
The Bottom Line
If you’re serious about gaining muscle strength and size, there may be some benefit to consuming a protein blend before bedtime. Doing so ensures that you get enough protein and that your muscles have round-the-clock access to amino acids, especially leucine, to jump start and sustain muscle protein synthesis and repair.
My Sports Science. “Protein intake before sleep results in greater muscle mass and strength”
ConsumerLab.com. ‘Product Review: Protein Powders, Shakes, and Drinks Reviews”
The Journal of Nutrition. “Protein Ingestion before Sleep Increases Muscle Mass and Strength Gains during Prolonged Resistance-Type Exercise Training in Healthy Young Men” 2015.
Nutrition Express. “Milk proteins: Whey and casein work better left together”
Fitness RX. October 30, 2012. “The Best Protein Supplements: Whey, Casein, and Soy”
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