For most people, losing weight isn’t easy but eating a high-protein diet makes it a little easier. Diets high in protein are more satiating and they have the added benefit of giving your resting metabolic rate a subtle boost. Now, new research from Purdue University shows another surprising benefit of eating a high-protein diet while losing weight – it could help you sleep better at night.
High-Protein Diet, Weight Loss, and Sleep
More protein for better sleep when you’re trying to lose weight? That’s what a new study shows. In this study, 44 obese and overweight adults consumed a lower calorie diet to promote weight loss for 16 weeks. One group ate the recommended amount of protein, 0.8 grams of protein per kilogram of body weight. This is roughly equivalent to consuming 0.36 grams of protein per pound of bodyweight. A second group ate 1.5 grams of protein per kilogram of body weight, almost twice the recommended amount. Over the course of the study, the participants consumed a variety of whole food protein sources, both animal and plant-based foods such as milk beef, soy, beans, and lentils.
Researchers also asked the participants to track the amount and quality of sleep they got over the course of the 16-week study. Surprisingly, those consuming a high-protein diet experienced better quality sleep than participants eating an “adequate” protein, low-calorie diet. Sleep quality in the study was independent of the TYPE of protein consumed. Simply consuming MORE protein of any kind while losing weight seemed to improve sleep quality.
Keep in mind, this is a small study and it’s too early to generalize and say eating a high-protein diet helps you sleep better, but it is an interesting observation that won’t necessarily hold true unless you’re actively restricting calories. Although researchers don’t know why a high-protein diet might improve sleep quality during periods of calorie restriction, it may have something to do with a hormone called cortisol.
Is Cortisol the Missing Link?
Cortisol, often dubbed the stress hormone, is a chemical messenger your body produces during times of emotional or physical stress, including calories restriction and starvation. Two small glands called the adrenal glands just above your kidneys, produce cortisol. One reason your adrenal glands manufacture more this hormone when stressed is to give you easy access to glucose during stressful periods when you might need more of it. Once the adrenal glands release cortisol, cortisol promotes the breakdown of glycogen and fat stores to send more fuel into your bloodstream. Cortisol also breaks down muscle tissue. That comes in handy when you’re stressed or starving since your liver can use the amino acids from the breakdown of protein to make glucose.
What does this have to do with high-protein diets during weight loss? When you lose weight, you not only lose fat but muscle as well. Your body perceives calorie restriction as stress and releases cortisol in response. When your serum cortisol rises in reaction to stress or calorie restriction, it interferes with sleep. Remember, cortisol is a stress hormone. Your body isn’t going to prioritize sleep when you’re physically or mentally stressed. Your body senses danger and wants you to be on high alert!
People who have a high cortisol level often have problems falling asleep and when they do, they may awaken too early in the morning and be unable to fall back to sleep. This may at least partially explain why people who consume more protein potentially sleep better when they’re calorie restricted. A high-protein diet reduces the rise in serum cortisol and offsets insomnia that goes along with it.
Another Reason to Eat More Protein When You’re Trying to Lose Weight
If you’re doing any kind of calorie restriction diet, consider increasing your protein intake. Doing so may also give you an edge towards shedding those pounds. In a study published in the American Journal of Clinical Nutrition, researchers found participants who increased the amount of protein in their diet from 15% of total calories to 30% ate more than 400 fewer calories over the course of a day. That’s impressive! It’s also an example of the satiety benefits protein offers.
Another reason – when you’re restricting calories, your body enters a catabolic state and breaks down muscle tissue. It’s the cortisol effect again. Increasing the protein content in your diet helps preserve lean muscle while you’re losing body fat. Of course, you should also resistance train to help preserve muscle tissue. Protein plus resistance training are the keys to preserving lean body mass.
Then there’s the thermic effect of protein. If you eat a meal that’s high in carbs versus one that’s high in protein, you’ll burn slightly more calories after eating the protein meal than the carb one. Plus, eating a protein meal or snack reduces cravings as well, so you’re less likely to snack on the wrong foods.
Of course, you don’t want to go on a very low-calorie diet due to the stress it places on your body. On the other hand, when you are reducing your calorie intake increasing the protein content of your diet works in your favor – and now it even seems it might even help you sleep better.
The Bottom Line
Whether or not eating more protein will help you sleep better when you’re not trying to lose weight isn’t clear but it may offer this additional perk if you are. Regardless, you might want to increase the amount of protein you’re consuming if you’re trying to lose weight. Doing so might make losing weight a little easier.
References:
Science Daily. “Losing Weight with a High-Protein Diet Can Help Adults Sleep Better” March 24, 2016.
American Journal of Clinical Nutrition, 2016. 103: (3): 766.
Am J Clin Nutr July 2005. vol. 82 no. 1 41-48.
J Am Coll Nutr. 2002 Feb;21(1):55-61.
Br J Nutr. 2010 Nov;104(9):1395-405. doi: 10.1017/S0007114510002060. Epub 2010 Jun 22.
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