Bedtime hunger is common, especially during full-throttle Spartan training. Dinner has long come and gone, and your growling stomach is becoming increasingly assertive. The message? You need protein before bed.

You resist, of course, because you’ve been programmed to believe that late-night snacking causes weight gain and sluggishness, but that's pure fiction. Pre-sleep snacking is not only okay, but it can actually be beneficial — especially when you're training hard, burning lots of calories, and need the fuel. 

Related: How Long Does the Anabolic Window Actually Last After a Workout?

However, before you order delivery or start filling up on processed snacks, here’s a caveat: Protein before bed is a great nighttime snack for athletes. But this snack should be moderately portioned and eaten about an hour before sleep. Depending on your size and energy expenditures, aim for a snack with 10 to 20 grams of protein and 200 to 300 calories. Here are some guidelines and ideas.

How Protein Before Bed Helps Athletes Recover

Encouraging muscle growth is perhaps of the biggest benefits of protein intake before falling asleep. According to experts, consuming protein between dinner and bedtime can help repair, maintain, and build new tissue in muscles that have been stressed by physical activity.

It’s true that eating a protein-rich snack after intense activity helps muscles recover and grow, but there’s also a window of opportunity to tap into the power of protein while you sleep. During the deep REM sleep stage, your body sends out its biggest blast of growth hormone. Consuming protein before crashing for the night helps feed the furnace to optimize workout gains. Eating a protein-rich snack can also help to stabilize blood sugar, keep you from waking up feeling starving, increase metabolism, and promote weight management, because more muscle burns more calories.

Related: These 50 High-Protein Foods Will Help You Hit Your Macros

Why Casein Protein Before Bed Is King

Not all proteins are created equal when it comes to pre-sleep eating. Animal proteins like beef, chicken, and fish are slower to break down and get put to good use by the body, seemingly sitting in the stomach all night. This fullness can make it hard to fall asleep or stay asleep if you’re easily bothered by reflux or heartburn. Even plant proteins like beans can cause uncomfortable gastrointestinal stress.

Protein powders — especially casein — and low-fat dairy products (which are naturally high in casein) are great late-night snack choices. Research shows that consuming casein protein before bed is a better choice than whey and other popular picks, as it’s digested and absorbed by the bloodstream at a slower rate. This keeps your muscles in a non-cannibalizing, anabolic state. This extended nutrient delivery is ideal for those 7 or 8 hours that you're asleep, recharging for your next day full of training.

Which Protein-Rich Bedtime Snacks Are Best?

Try various smoothies, shakes, and “sundaes” using low-fat varieties of milk, Greek yogurt, or cottage cheese — all of which are high in casein protein. Add a handful of berries or tablespoon of nut butter for flavor. You can also try freezing smoothies in ice cube trays or pop molds for a frozen treat. Milk with granola or protein-fortified cereal is an easy fix.

Related: 5 Protein Smoothie Recipes You'll Actually Want to Drink

If you're in the mood for something savory, half a sweet potato with cottage cheese is a great choice. Those who are lactose-intolerant can safely consume casein in a non-dairy format: Just look for casein protein isolate powder on the health food aisle of your market.

Casein and lactose are two completely different parts of milk, with the former being milk proteins and the latter being milk sugars. (So don't worry if you're lactose intolerant.) The calcium and tryptophan found in dairy work together to manufacture sleep-inducing and sleep-regulating melatonin.