For years now we've been told to avoid eating late at night: Eat past eight = gain weight, right? Not necessarily.

The truth is that nothing magical happens within your body when the clock strikes 8 p.m. You might become more sedentary and burn fewer calories, but closing down the kitchen too early may be slowing down your results.

The "don't eat at night" theory seems pretty logical at first glance; after all, the earlier you consume calories, the more time you have to burn them off throughout the day. Some studies have found that, in some cases, healthy adults burn fewer calories digesting a meal at night than during the day.1 Other research claims that nighttime eating might not keep you as full as daytime eating.2 However, there are two factors to keep in mind when interpreting studies like these:

• Many studies are done on very specific populations, so the results may not be applicable to everyone.
• Some research, such as the oft-cited study that showed greater weight gain in mice during a time when they were normally sleeping, uses rodents, which may be affected differently than humans.3 An interesting find indeed, but I was told to never trust a rat.

Eating at night may be counterproductive to your physique if it's the only meal you eat all day or you save up all of your calories for an evening snack, but the last time I checked, most serious bodybuilders and athletes don't do this. You've been taught to eat every 3-4 hours to maximize protein synthesis, so why change that routine at the end of the day?

Don't Skip the Exercise!

Having a bedtime snack curbs your appetite, but it can also increase insulin levels and insulin resistance.8 High insulin levels cause you to store fat rather than burning it. The easiest way to prevent this is by engaging in exercise! Research showed that women who ate a bedtime snack for four weeks, but also exercised three days per week, observed no increase in their insulin levels.9

According to a recent review article, you should stop being afraid to chow down after sundown. It's more important to focus on what you eat at night, rather than what time you eat.4

Choosing the Right Nighttime Snack

Picking the right foods is essential for keeping your body in an anabolic state and setting the stage for optimal muscle growth and recovery during sleep. Your best bet for a nighttime snack is protein. Whey is the most common type found in protein supplements, but casein is traditionally thought to be the best to consume before bed. It's released from the stomach and absorbed into the blood stream more slowly than whey, making it ideal for prolonged anabolism during overnight sleep.

Protein at Bedtime to Boost Your Gains

Researchers in the Netherlands have shown that consuming 40 grams of casein post-exercise, but within 30 minutes of going to bed, resulted in greater muscle protein synthesis (compared to a noncaloric placebo).5

More recently, a study in the Journal of Nutrition showed a that a protein supplement (27.5 grams of protein, 15 grams of carbohydrates, and 0.1 grams of fat) ingested before sleep led to an increase in muscle mass and strength during a 12-week resistance-training program, compared to a placebo.6 That's even more support for nighttime eating and gains!

"According to a recent review article, you should stop being afraid to chow down after sundown. It's more important to focus on what you eat at night, rather than what time you eat. 4"

Nighttime Protein to Increase Weight Loss

Supplementing with a protein shake before hitting the sheets may also help you lose fat and increase lean mass. Researchers out of Florida State University have conducted several nighttime feeding studies. Here's what they found:

Having a nighttime snack can boost your metabolism

Healthy, physically active college-aged men who consumed whey, casein, or carbs 30 minutes before bed had a higher resting energy expenditure (REE) the next morning when compared to a placebo group.7 Findings from this study suggest that regardless of the macronutrient type, consuming a liquid supplement near bedtime may be beneficial for those trying to lose or maintain weight.

Protein may help regulate your appetite

Consuming protein can help you feel fuller throughout the night and make you want to eat less the next morning.8 Casein may prove to be the better overnight option; in one study, overweight women felt fuller after consuming casein compared to those who ate whey or carbs at night. 9 Having a casein snack before bed may actually reduce the amount of food you eat overall!

From these studies, we can safely conclude that bodybuilders and athletes may benefit from consuming protein before bed rather than going to bed on an empty stomach, especially if they want to maximize their calorie-burning potential.

Furthermore, casein may be better than whey, as it promotes overnight muscle growth and may help you burn fat.

Your Smart Bedtime-Snack Cheat Sheet

• Eat meals at regular intervals throughout the day.
• Have an additional snack within 30 minutes of going to bed.
• Choose a snack made up mostly of protein.
• Choose casein protein over whey when possible.
• Shoot for less than 200 calories and 30-40 grams of protein.

High-casein snack foods

• 1 cup cottage cheese
• 8 ounces Greek yogurt
• 2 cups milk
• 1 scoop casein powder with 1/2 cup milk

References

1. Romon, M., Edme, J. L., Boulenguez, C., Lescroart, J. L., & Frimat, P. (1993). Circadian variation of diet-induced thermogenesis. The American Journal of Clinical Nutrition, 57(4), 476-480.
2. de Castro, J. M. (2004). The time of day of food intake influences overall intake in humans. The Journal of Nutrition, 134(1), 104-111.
3. Arble, D. M., Bass, J., Laposky, A. D., Vitaterna, M. H., & Turek, F. W. (2009). Circadian timing of food intake contributes to weight gain. Obesity, 17(11), 2100-2102.
4. Kinsey, A. W., & Ormsbee, M. J. (2015). The Health Impact of Nighttime Eating: Old and New Perspectives. Nutrients, 7(4), 2648-2662.
5. Res, P.T., Groen, B., Pennings, Beelen, M., Wallis, G. A., Gijsen, A. P., Senden, J. M., & Van Loon, L. J. (2012). Protein ingestion before sleep improves postexercise overnight recovery. Medicine and Science in Sports and Exercise, 44(8), 1560-1569.
6. Snijders, T., Smeets, J. S., van Vliet, S., van Kranenburg, J., Maase, K., Kies, A. K., ... & van Loon, L. J. (2015). Protein Ingestion before Sleep Increases Muscle Mass and Strength Gains during Prolonged Resistance-Type Exercise Training in Healthy Young Men. The Journal of Nutrition, jn208371.
7. Madzima, T. A., Panton, L. B., Fretti, S. K., Kinsey, A. W., & Ormsbee, M. J. (2014). Night-time consumption of protein or carbohydrate results in increased morning resting energy expenditure in active college-aged men. British Journal of Nutrition, 111(01), 71-77.
8. Kinsey, A. W., Eddy, W. R., Madzima, T. A., Panton, L. B., Arciero, P. J., Kim, J. S., & Ormsbee, M. J. (2014). Influence of night-time protein and carbohydrate intake on appetite and cardiometabolic risk in sedentary overweight and obese women. British Journal of Nutrition, 112(03), 320-327.
9. Ormsbee, M. J., Kinsey, A. W., Eddy, W. R., Madzima, T. A., Arciero, P. J., Figueroa, A., & Panton, L. B. (2014). The influence of nighttime feeding of carbohydrate or protein combined with exercise training on appetite and cardiometabolic risk in young obese women. Applied Physiology, Nutrition, and Metabolism, 40(1), 37-45.