Parents receive mixed messages about food and sleep. Some sources say tryptophan in turkey helps children sleep. Others recommend warm milk before bed. Websites warn against sugar causing sleep problems. Health blogs promote specific “sleep-promoting” foods. With so much conflicting advice, what should you tell families?
A research paper titled “Influence of nutrition and food on sleep-is there evidence?” by Netzer, Strohl, and Pramsohler (2023) examined this question systematically. Published in Sleep and Breathing, the study reviewed over 4,000 research publications to answer one question: do specific foods or diets actually affect sleep? The conclusion challenges common beliefs. The authors found no direct evidence that certain foods or diets improve or worsen sleep. While this paper reviews research across all ages, its findings have important implications for child sleep consultants working with families who ask about food and sleep.
What the Researchers Did
The research team followed strict scientific methods called PRISMA guidelines. They searched for studies published between 2012 and 2022 using keywords like “sleep,” “sleep disorders,” “nutrition,” and “food intake.” They excluded studies about weight loss diets for treating sleep apnea, studies about connections between sleep disorders and metabolic disorders, and studies about drugs affecting sleep.
From 4,155 publications, they found only 988 that actually focused on nutrition, metabolism, and sleep together. After careful review, just 26 studies met their requirements for examining how specific foods or diets influence sleep.
This small number tells us something important: despite decades of research and many popular beliefs, we have very little solid evidence about food directly affecting sleep.
The Main Finding: No Direct Evidence
The paper’s conclusion is clear and surprising. The authors state: “There is no evidence of a direct influence of certain nutrition or food intake on sleep.” This does not mean food and sleep are unrelated. It means the connection works differently than most people think.
The research shows that sleep influences eating behavior much more than eating influences sleep. When people sleep poorly or sleep too little, their food choices change. They tend to eat more calories, choose less healthy foods, and gain weight. But eating certain foods does not appear to directly improve or worsen sleep quality.
The authors conclude: “Epidemiologic surveys suggest that shortened or fragmented sleep and chronotype in adults influence nutrition and fat metabolism.” The direction of effect goes from sleep to food, not from food to sleep.
What About Common Beliefs?
Many parents believe specific foods help children sleep. The research found no support for most of these ideas. One study examined whether eating more protein affects sleep in adults. The meta-analysis concluded there is no real effect on sleep itself. Some people reported feeling their sleep improved, but this was subjective opinion from questionnaires, not measured sleep quality.
A Japanese study looked at breakfast types in adults and whether people were morning or evening types. People who ate traditional Japanese breakfasts said they were more morning-oriented. But this study relied entirely on questionnaires. People who already consider themselves healthy and morning-oriented might naturally report eating healthier breakfasts. The study cannot prove that breakfast type causes changes in sleep patterns.
The paper states clearly about this research: “A direct influence on sleep or sleep-wake cycle by food cannot be concluded from these two reports.”
Research Specifically in Children and Adolescents
The paper includes a substantial section reviewing studies on nutrition and sleep in young people. This section is most relevant for child sleep consultants. The paper reviewed 24 articles about sleep and nutrition in children. Most studies linked missing nutrients and high sugar intake with shorter sleep time in obese children. But these were correlations, not cause and effect. A minority of these studies presented a link between obesity and food with sleep parameters.
Chinese studies found that adolescents who ate carbohydrates late at night slept less. But these same adolescents also had depression and other mental health issues that affect sleep. The paper notes this complicates the findings. Young Chinese athletes with healthy diets slept better, but they also lived healthier lifestyles overall. Which factor actually improved their sleep? The studies cannot tell us.
One study surveyed over 800 students about diet and sleep quality. Students who ate more sweets and meat and fewer vegetables had worse sleep. But 67% of participants were young women who already considered themselves healthy eaters. This creates bias in the results. The paper identifies “a number of issues that biased the outcome of the investigation.”
The pattern repeats across studies on children and adolescents. Children who sleep less tend to eat more fast food and processed foods. They spend more time gaming or online. But does the food cause poor sleep, or does staying up late lead to eating more junk food? The research suggests the second explanation is more accurate.
A systematic review examined 61 studies on children, adolescents, and young adults. These studies looked at sleep duration, time online, computer gaming, and consumption of fast food or ultra-processed foods. Almost all studies found correlations between short sleep, late-night activities, increased consumption of ultra-processed food, and risk for obesity. But the paper states clearly: “none of these investigations showed direct disruption of sleep or shortening of sleep by intake of ultra-processed food. A direct connection between length of sleep and particular food intake has not been established.”
One study of 850 students (equally divided between genders) found that morning chronotype affected BMI and eating behavior. But the study showed that questionnaire results for sleep, chronotype, and eating behavior differ at different time points in adolescents and young adults. This means the relationships are not stable or consistent.
Another study found that eating behavior and late sleep onset time do not differ much between adolescents and adults.
What Parents Try: Coffee and Food Timing for Children
The paper describes an interesting survey of nursing home staff caring for residents with dementia. This example shows how common beliefs about food and sleep persist even among caregivers. Nursing staff often encourage residents to eat well during daytime and have only a snack for dinner, believing this keeps residents asleep at night. If residents still wake up at night with chaotic sleep-wake cycles, staff give them coffee or tea and keep them busy to make them tired.
The authors note: “While this seems a practical approach in elderly demented patients, the authors concluded that the caffeine delivery negatively influences the sleep-wake cycle.” But the paper also states: “There has been no controlled trial to determine if certain food, certain amounts of food, or certain meal times may help persons with dementia to sleep at night.”
This example shows how beliefs about food timing and sleep persist without scientific testing. Parents may try similar approaches with children, but we lack evidence that these strategies work.
Sleep Restriction and Weight Gain: Important Adult Research
One rigorous study provides strong evidence for how sleep affects eating, but this research was conducted in adults. Researchers studied 224 adult participants in a randomized controlled trial. They restricted sleep in 198 participants to just 4 hours in bed per night for 5 nights. The control group of 27 participants got 10 hours in bed. The sleep-restricted adults ate 527 extra calories per day compared to control subjects. Sleep-restricted adults gained an average of 0.86 kg during the study period.
This shows a clear mechanism in adults: when people don’t sleep enough, they eat more. While this study was not done in children, it provides the strongest evidence for the direction of effect. The paper states: “The study results strongly suggested a connection between sleep restriction and weight gain.”
For child sleep consultants, this research suggests that poor sleep may influence eating behavior. Improving sleep may help with healthy eating habits, but changing diet alone will not fix sleep problems.
Another adult study examined timing of food intake. The research measured the influence of circadian rhythm on hormone-sensitive lipase, a fat-dissolving enzyme in adults. Results showed that eating dinner late (after 10:00 pm) reduced the effect of lipase. With lipase most active around midnight, longer fasting at night was associated with higher fat mobilization and fat burning. The paper states: “The findings suggest that the sleep-wake cycle affects the role of fat dissolving enzymes on metabolism.” But this study did not measure sleep quality itself.
A trial followed mildly obese adult women for several weeks on the MIND diet (Mediterranean-DASH Intervention for Neurodegenerative Delay Diet). This diet combines low carbohydrates and saturated fat with increased unsaturated fat and vegetables. The study found no influence of this diet on sleep quality measured by the Pittsburgh Sleep Quality Index questionnaire.
The paper states clearly: “Unfortunately there are no human studies that investigate how nutrition may influence sleep.” Other weight loss programs and diets in adults have been unable to show any influence on sleep parameters, though there may be gender differences in weight loss success.
The Science Behind Fat and Sleep: Animal Research
The paper explains biological mechanisms that connect sleep and metabolism. But the authors clearly state: “Most of this neuronal and mediator research has been performed in animals. It remains to be seen if these findings can be substantiated in human physiology.”
This is important. The science about how fat cells (adipocytes) produce hormones that affect sleep comes from animal studies, primarily in mice. We cannot directly apply these findings to human children.
The paper explains: “According to molecular research, a key for nutritional influence on sleep, sleep quality, and sleep disorders lies in the production of mediators in adipocytes.” Both white and brown fat cells may play a role in circadian rhythm. White fat can become brown fat or intermediate beige fat and vice versa. Brown fat cells are the most productive of signaling agents.
In animals, fat cells produce hormones including leptin and adiponectin that affect brain areas controlling sleep and wakefulness. Adiponectin increases wakefulness during the rest phase and activates wake-promoting neurons. Leptin promotes REM and NREM sleep and increases delta power during NREM sleep.
Brown fat cells produce a protein called UCP1 that interacts with melatonin. Melatonin stimulates browning of fat cells and production of UCP1. UCP1 then stimulates melatonin expression and stabilizes circadian rhythm and sleep. If melatonin stimulation is disrupted, the browning of white fat is disrupted. The paper suggests: “This may be one explanation on a molecular basis for weight gain associated with insufficient total sleep time.”
But all of this is animal research. The paper’s conclusion states: “Obesity via adipocyte signaling may influence the sleep-wake cycle, though the molecular research on this topic is based on animal studies.”
Some animal studies suggest certain spices like curcumin (found in saffron, thyme, and cinnamon) and quercetin (in onions) might affect fat cells. Other substances like pepper and capsaicin may work only in combination with other compounds. But the paper notes: “Research on these spices and chemicals is restricted to knock out mice… The application of these findings to humans remains speculative in view of the large doses of chemicals used in this animal research.”
What About Caffeine?
The paper notes that caffeine clearly affects sleep. Early research investigated the influence of caffeine and other methylxanthines on sleep structure, sleep quality, and insomnia. This topic has gained attention recently because of increasing consumption of taurine and caffeine-containing energy drinks in teenagers and adolescents. Energy drink consumption is thought to be a reason for fragmented and short sleep in school children and students.
But the paper states: “Caffeine is clearly a neuroactive substance but it is not regarded as a food substance” for the purposes of this review. As child sleep consultants, recommending that families avoid giving children caffeine-containing drinks and energy drinks remains sound advice based on evidence.
The paper also discusses alcohol, noting it initially makes people sleepy by inducing slow wave sleep but then disrupts sleep quality throughout the night as the effects change. This research applies to adults.
Problems With Current Research
The paper points out significant problems with existing studies, particularly in children. Most research on food and sleep in children relies on questionnaires. Parents or children report their own eating habits and sleep quality. This creates several issues:
People who believe they eat healthily tend to report better sleep, regardless of actual sleep quality. Few studies use objective measurements like actigraphy or polysomnography to confirm what questionnaires report. Studies cannot separate whether diet affects sleep, or whether believing you eat well makes you think you sleep well.
Many studies mix multiple factors. A child who stays up late gaming, eats junk food, and sleeps poorly might have poor sleep because of screen time, not because of food. Most studies cannot separate these different influences.
A recent meta-analysis examined 24 studies on food intake and sleep. The analysis concluded that morning chronotype has healthier eating behavior than evening chronotype, who eats more fat and carbohydrate-containing food. But the paper notes: “All the analyzed studies were based on subjective questionnaires. There have been no data derived from objective measurement of sleep or activity via actigraphy.”
Practical Implications for Sleep Consultants
What does this research mean for your work with families? Several practical lessons emerge:
First, you can tell parents that no specific food will make their child sleep better. This includes warm milk, turkey, bananas, or any other commonly suggested “sleep foods.” The research found no evidence supporting these claims. If parents have tried these and feel they work, the benefit likely comes from the bedtime routine or placebo effect, not the food itself.
Second, focus your recommendations on sleep practices rather than dietary changes. The research shows no evidence that changing what a child eats will fix sleep problems. The paper’s conclusion is clear on this point.
Third, when families mention their child’s weight concerns, recognize that poor sleep might contribute to unhealthy eating. Adult research clearly shows this connection. While similar controlled studies have not been done in children, the pattern of correlation in child studies suggests the same direction of effect. Improving sleep might support healthier food choices, but this is a secondary benefit of good sleep, not the primary goal.
Fourth, continue to recommend avoiding caffeine and energy drinks for children and adolescents. The evidence about caffeine’s negative effects on sleep remains strong and is specifically mentioned for children in this paper.
Fifth, be cautious about meal timing advice. The traditional saying “Have breakfast like an emperor, eat lunch like a king, and dine like a beggar” has not been proven to improve sleep. The paper mentions this traditional advice but states: “The scientific evidence for this traditional life advice should be examined.” One adult study suggested that eating dinner very late (after 10:00 pm) might affect fat metabolism, but this research did not measure sleep quality.
What Parents Should Know
Parents come to you with many questions about food and sleep. They have read conflicting advice online and from different sources. This research helps you give accurate answers based on systematic review of evidence.
You can explain that while nutrition matters for overall health, current research shows no direct evidence that specific foods or diets control whether their child sleeps well. The connection exists, but it works the opposite way: sleep quality affects food choices.
If parents insist on connecting food to their child’s sleep problems, redirect the conversation. Ask about bedtime routines, sleep environment, wake time consistency, screen time, and daytime sleep. These factors have much stronger evidence supporting their influence on sleep quality.
When parents report their child sleeps poorly and eats lots of sweets or junk food, acknowledge both concerns. But explain that the research shows sleep problems likely lead to poor food choices, rather than poor food choices causing sleep problems. Helping the child sleep better may naturally improve their eating habits.
Limitations and Future Research Needs
This paper makes clear that most research has significant limitations. Studies on children rely heavily on questionnaires without objective sleep measurement. Most studies cannot separate the many factors that affect both sleep and eating in children.
The biological mechanisms connecting sleep and metabolism come from animal studies. The paper’s conclusion emphasizes this: “Obesity via adipocyte signaling may influence the sleep-wake cycle, though the molecular research on this topic is based on animal studies.” We need human research, particularly in children, to know if these mechanisms apply.
Future research should use objective sleep measurements like actigraphy or polysomnography alongside careful diet tracking. Studies need larger sample sizes and better controls for factors like screen time, physical activity, and mental health. Research should focus specifically on children rather than mixing children and adults, since sleep needs and eating patterns differ significantly between age groups.
The paper found that only 26 out of 4,155 publications met basic requirements for examining how food affects sleep. This shows how little quality research exists on this topic despite widespread public interest.
Netzer, N.C., Strohl, K.P. & Pramsohler, S. Influence of nutrition and food on sleep-is there evidence?. Sleep Breath 28, 61–68 (2024). https://doi.org/10.1007/s11325-023-02921-1