Switching to a high-protein diet has its health benefits, including weight loss and muscle gain. According to a new study conducted by researchers from Purdue University, people who eat more protein than carbohydrates may also sleep better. Their findings, published in The American Journal of Clinical Nutrition, reveal how a simple diet change can help people lose weight and get more and better sleep.

For the preliminary study, researchers asked 14 participants to consume more dietary protein during four weeks of a weight loss regimen. Each participant’s diet constituted either 10 percent, 20 percent, or 30 percent of protein. Meanwhile, according to the U.S. Department of Agriculture, in a normal adult diet, roughly 10 to 35 percent of total calories should come from protein. They found those who ate more protein not only experienced additional weight loss but also reported better-quality sleep based on the Pittsburgh Sleep Quality Index, which evaluates sleep on the basis of several factors, including duration and quality, plus a person's habits, daytime function, frequency of nighttime disturbances and medication use.

Next, researchers examined 44 overweight and obese participants who ate either a normal-protein or high-protein diet designed for weight loss. Participants who followed the high-protein diet lost weight and reported a higher quality of sleep for up to four months after the dietary intervention, compared to those who ate a normal amount of protein.

"Most research looks at the effects of sleep on diet and weight control, and our research flipped that question to ask what are the effects of weight loss and diet -- specifically the amount of protein -- on sleep," said Wayne Campbell, a nutrition science professor at Purdue University, in a statement. "We found that while consuming a lower calorie diet with a higher amount of protein, sleep quality improves for middle-age adults. This sleep quality is better compared to those who lost the same amount of weight while consuming a normal amount of protein."

Sleep is the key to maintaining a healthy body, especially as a person ages. Most people know it’s important to get a good night’s sleep, but very few Americans clock in eight hours each night, according to the National Sleep Foundation. Adults need approximately seven to nine hours of sleep each night for optimum performance, health, and safety. Although a high-protein diet has been found to improve sleep quality, a lack of sleep has been linked to health problems including obesity, high blood pressure, negative mood and behavior, decreased productivity, and safety issues at home, work, or behind the wheel.

"Short sleep duration and compromised sleep quality frequently lead to metabolic and cardiovascular diseases and premature death," said the study’s co-author Jing Zhou, a doctoral student in nutrition science at Purdue University, in a statement. "Given the high prevalence of sleep problems, it's important to know how changes to diet and lifestyle can help improve sleep."

How To Eat For Sleep

Participants in the study were fed a diet of beef, pork, soy legumes, or milk protein, along with an additional 750 calories worth of fats and carbohydrates. Similar dietary benefits can be reaped from other protein sources that are both rich in nutrients and low in saturated fats and calories. Lean meats, seafood, beans, soy, low-fat dairy, eggs, nuts, and seeds are all proteins to rotate into the diet.

While keeping protein intake high, it’s important to help the body process all that protein with a limited amount of carbohydrates. But that doesn’t mean carbo-loading with pasta, potatoes, and cookies. But instead, choose smart carbs like whole grains, fruits, vegetables, and yogurt.

Campbell and his research team plan to examine how other protein sources and dietary patterns affect appetite, body weight, and composition.

"This research adds sleep quality to the growing list of positive outcomes of higher-protein intake while losing weight, and those other outcomes include promoting body fat loss, retention of lean body mass and improvements in blood pressure," Campbell said. "Sleep is recognized as a very important modifier of a person's health, and our research is the first to address the question of how a sustained dietary pattern influences sleep."

Source: Zhoue J, Kim JE, Armstrong CLH, Chen N, and Campbell WW. High-protein diets improve indexes of sleep in energy-restricted overweight and obese adults: results from 2 randomized controlled trials . The American Journal of Clinical Nutrition . 2016.