Overweight people who lose weight on a high-protein diet have better sleep, according to a study from Purdue University published in the American Journal of Clinical Nutrition.

"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 professor of nutrition science. "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."

A pilot study with 14 participants found that consuming more dietary protein in a weight loss program leads to better sleep after four weeks. The main study was conducted with 44 overweight or obese participants who were either on a normal protein diet or on a high-protein diet. After three weeks of adapting to the program, participants were divided into two groups. The first group consumed 0.8 grams of protein per kilogram of body weight daily for 16 weeks, and the second group - 1.5 grams. The sources of protein used in both groups ranged from beef, pork, soy, legumes, and dairy products. Each month, participants completed a questionnaire to assess the quality of their sleep, and those who consumed more protein reported an improvement.

Campbell's lab has also studied how the amount and sources of protein in food affect appetite and 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."

References:

J. Zhou, J. E. Kim, C. L. Armstrong, N. Chen, W. W. Campbell. Higher-protein diets improve indexes of sleep in energy-restricted overweight and obese adults: results from 2 randomized controlled trials. American Journal of Clinical Nutrition, 2016; 103 (3): 766 DOI: 10.3945/ajcn.115.124669