Your high-protein diet is not wrecking your sleep

Poor sleep is increasingly treated as a public health issue in its own right, and diet is one of the first levers people reach for when their nights go wrong. Protein has attracted growing interest as a possible route to better sleep, yet the evidence has been limited and inconclusive. The question also cuts the other way: high-protein eating is popular among people who train, and some of them quietly wonder whether all that protein disturbs their rest. This review set out to settle what the trial evidence actually shows about raising protein intake and sleep in adults.

On 30 November 2021 the authors searched five electronic databases, including PubMed, Cochrane, Embase, Web of Science and CINAHL Plus, for randomised controlled trials of increased protein intake in adults. Increased intake was defined as at least 1 g per kilogram of body weight per day, at least 25% of total energy from protein, or supplementation of at least 10 g per day. Twelve intervention studies reported across 10 articles were included. The review tracked sleep quality, sleep latency, sleep efficiency, sleep time and wake episodes, pooled four of these outcomes, judged each trial's risk of bias with the Cochrane tool, and graded the certainty of evidence.

The headline result is a null: pooled analyses showed no significant effect of increased protein intake on sleep quality, sleep time, sleep latency or sleep efficiency, drawing on 8, 8, 7 and 6 studies respectively. The qualitative read of the included trials pointed the same way, with only subjective sleep quality showing a positive link to protein in a few studies. When the authors re-ran the numbers excluding trials at high risk of bias, a small effect in favour of higher protein emerged for sleep quality, a difference of 4.28 points on a scale from 0 to 100. The certainty of evidence was rated very low throughout.

Individual studies on protein and sleep have pointed in different directions, and this pooled answer is that no clear relationship exists in either direction. That cuts both ways: it deflates any hope that protein is a simple sleep aid, and it equally undermines the worry that a high-protein diet disturbs sleep. The authors are candid that the strength of the evidence is low, and they call for more randomised controlled trials built specifically around this question. The hint of benefit in the stronger trials keeps the door ajar rather than closing it.

If you eat a high-protein diet to support training or body composition, this review offers no reason to think your sleep is suffering for it. If you were considering raising protein specifically to sleep better, the pooled evidence does not support that as a strategy, beyond one tentative hint that subjective quality might improve slightly. The honest summary is that protein intake and sleep appear largely independent on current evidence. Judging your protein by its established roles, rather than expecting it to move your nights, fits what these trials show.