Having a hard time falling asleep on some or most nights? It could be affecting your weight. But new research suggests that eating more protein while reducing your calories can improve sleep while helping you achieve greater fat loss (1).

How well people sleep each night has recently been a target of research because it’s thought to be an indicator of whether or not they are successful in losing weight. Now new research from scientists at Purdue University suggests that getting more protein each day while reducing calories may be key to sound sleep and greater fat burning.

Previous research had already established that higher protein intake leads to preserving lean body mass in those looking to shed extra weight (2). Quality of sleep had also been a determining factor in fat-loss success (3). However, past research on diet had not yet looked at the relationship between the two for improving diet, weight management, and overall health (4-6).

In the new study, scientists set out to answer the question, “How is sleep affected by a higher protein intake?”

Two Randomized Controlled Studies

Jing Zhou and colleagues evaluated the effect of protein intake on sleep during weight loss in middle-aged overweight adults in two randomized, controlled intervention studies:

  • The first study assessed the effects of protein quantity from either animal or vegetable sources on appetite response. The scientists randomized 14 subjects to a diet with either low protein (10 percent of total calories), medium protein (20 percent of total calories), or high protein (30 percent of total calories) for four weeks. Over the duration, the researchers assessed a global sleep score and sleep quality index.
  • The second study aimed to investigate the effects of higher protein intake on fat loss and metabolic health. The scientists randomized 44 subjects to either a normal-protein diet (0.8 gram per kilogram) or a high-protein diet (1.5 grams per kilogram) while being in a 750-calorie deficit for 16 weeks.

Afterward, the researchers found consistently better global sleep scores for subjects eating higher protein from both studies. In the first study, the high-protein group had improved global sleep scores, while in the second study, the global sleep improved only in the high-protein group and not the normal-protein group.

The combined results of both studies suggest that higher protein intake improves sleep during normal calorie consumption and when reducing calorie intake for weight loss.

How Sleep Works to Help You Lose Weight

The findings of better sleep helping support weight loss is unsurprising, judging from the increasing evidence from laboratory and epidemiologic studies indicating that insufficient sleep is actually a risk factor for obesity (6, 7). Among the reasons is that reduced amount or quality of sleep is thought to stimulate hunger and can lead to eating too much or having more frequent occasions to eat (6).

Authors of another newly published study point to the involvement of reward mechanisms in the brain for overeating during periods of reduced sleep (7). Activation of the endocannabinoid (or eCB) system is a key component of the overeating pathways involved in appetite and food intake.

In their randomized crossover study, Hanlon and colleagues examined eCB over four nights of eight and a half hours of normal sleep versus four and a half hours of restricted sleep in healthy, young adults. They also assessed hunger, appetite, and food intake under controlled conditions over a 24-hour period.

Interestingly, when sleep-deprived, the study participants reported increases in hunger and appetite that matched the afternoon elevation of eCB and were more prone to eating snacks.

The new research on the brain’s appetite system is quite complicated, but the message is clear to anyone who is trying to lose weight: Make quality sleep a priority.

Eat higher amounts of protein to not only help preserve lean body mass when trying to reduce body fat, but also to aid in supporting better sleep. Strive for a normal sleep pattern where you are averaging seven to nine hours of sleep a night, and finally, be consistent over time for long-term weight management.


  1. Zhou J, Kim JE, Armstrong CL, Chen N & Campbell WW. Higher-protein diets improve indexes of sleep in energy-restricted overweight and obese adults: results from 2 randomized controlled trials. Am J Clin Nutr. 2016 Feb 10. pii: ajcn124669. [Epub ahead of print]
  2. Leidy HJ, Carnell NS, Mattes RD & Campbell WW. Higher protein intake preserves lean mass and satiety with weight loss in pre-obese and obese women. Obesity. 2007 Feb; 15(2):421-9.
  3. Thomson CA, Morrow KL, Flatt SW, Wertheim BC, Perfect MM, Ravia JJ, Sherwood NE, Karanja N & Rock CL. Relationship between sleep quality and quantity and weight loss in women participating in a weight-loss intervention trial. Obesity. 2012 Jul; 20(7):1419-25.
  4. Brunner EJ, Wunsch H & Marmot MG. What is an optimal diet? Relationship of macronutrient intake to obesity, glucose tolerance, lipoprotein cholesterol levels and the metabolic syndrome in the Whitehall II study. Int J Obes Relat Metab Disord. 2001 Jan; 25(1):45-53.
  5. Cecchini M, Sassi F, Lauer JA, Lee YY, Guajardo-Barron V & Chisholm D. Tackling of unhealthy diets, physical inactivity, and obesity: health effects and cost-effectiveness. Lancet. 2010 Nov 20; 376(9754):1775-84.
  6. Filiatrault ML, Chaput JP, Drapeau V & Tremblay A. Eating behavior traits and sleep as determinants of weight loss in overweight and obese adults. Nutr Diabetes. 2014 Oct 20; 4:e140.
  7. Hanlon EC, Tasali E, Leproult R, Stuhr KL, Doncheck E, de Wit H, Hillard CJ & Van Cauter E. Sleep Restriction Enhances the Daily Rhythm of Circulating Levels of Endocannabinoid 2-arachidonoylglycerol. Sleep. 2015 Nov 19. pii: sp-00259-15. [Epub ahead of print]