Purdue University researchers found that a high-protein diet improves the sleep of overweight and obese adults who are losing weight with the diet. The study published in the American Journal of Clinical Nutrition states that the benefits can be seen in as early as three to four months after the dietary change.

“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,” says nutrition science Professor Wayne Campbell. “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.”

Initially, the team’s pilot study involved 14 individuals who ate more foods high in protein who slept better after four weeks of weight loss. They conducted their main study that included 44 overweight or obese people.

Purdue University's Wayne Campbell, a professor of nutrition science. Photo from Purdue University

Purdue University’s Wayne Campbell, a professor of nutrition science. Photo from Purdue University

Some consumed a normal-protein weight loss diet while others consumed a high-protein weight loss diet. When these participants got used to the diet, a dietitian designed their diet that consisted of 0.8 or 1.5 kilogrammes of protein for each body weight kilogramme to be eaten daily for 16 weeks.

The participants’ daily caloric needs have also been considered. Protein sources included beef, pork, milk protein, legumes and soy.

Based on the survey that rated their sleep quality throughout the study, those who consumed the high-protein diet experienced an improvement in their sleep quality. These improvements were observed three and four months after the dietitian introduced this dietary modification.

Study’s first author Jing Zhou adds that their study suggests that those who want to sleep better need to consider modifying their diet and lifestyle, which may include consuming high-protein food. Nevertheless, more research is still needed to verify the study’s findings.

“Sleep is recognised 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,” Campbell asserts. “We’ve shown an improvement in subjective sleep quality after higher dietary protein intake during weight loss, which is intriguing and also emphasises the need for more research with objective measurements of sleep to confirm our results.”