Eating for Better Sleep & Foods that Improve Metabolic Health | Dr. Marie-Pierre St-Onge

Initial research indicated that higher fiber intake was associated with more deep sleep, while increased saturated fat consumption correlated with less deep sleep. Furthermore, consuming refined carbohydrates or simple sugars led to more arousals during sleep, hindering the attainment of optimal slow-wave and REM sleep.

Research consistently demonstrates a correlation between sleep restriction and increased pleasurable food consumption. Meta-analyses have shown overeating by 250 to 400 calories when sleep is restricted, which accumulates significantly over time due to the relationship between excess calories and body weight (approximately 3,500 calories per pound). This effect is particularly relevant for individuals experiencing night shifts, new parenthood, or caring for sick relatives.

A 2022 study by Naima Covassin found that sleep restriction (5 hours vs. 7.5 hours per night) for just two weeks resulted in participants gaining half a kilogram, roughly equivalent to one pound. This highlights the significant impact of even short-term sleep deprivation on metabolic health and weight management, demonstrating how easily weight can be gained without any other lifestyle changes.

Contrary to expectations based on stress research, a study examining the impact of sleep restriction (4 hours per night for 5 days) did not show significant changes in cortisol levels. This suggests that the physiological stress response isn't always directly linked to sleep deprivation, particularly when individuals are in controlled lab environments with minimal external stressors.

While a controlled study showed no adverse effects on glucose or insulin, researchers observed that metabolic abnormalities are prevalent in free-living populations with insufficient sleep. This suggests that the combination of poor sleep, less sedentary behavior, and unhealthy dietary choices (higher fat, sugar, salt) compounds to create cardiometabolic risks not seen in lab settings.

Researchers found that a diet closely aligned with the Mediterranean diet was associated with better sleep duration and reduced insomnia symptoms in a cohort. This finding launched further studies examining the relationship between diet quality and sleep, including analysis of data from the Women's Health Initiative.

A unique approach in longitudinal studies involves tracking individuals over time while accounting for baseline conditions. In this study, researchers categorized participants based on their insomnia status at both the beginning and 3-year follow-up points – those with consistent sleep, those who improved, and those with persistent or developing insomnia.

The DASH (Dietary Approaches to Stop Hypertension) diet, which emphasizes fruits, vegetables, nuts, seeds, low-fat dairy and plant-based foods, was also examined. Women following a dietary profile closer to the Mediterranean or DASH diets were found to be less likely to experience insomnia at the 3-year mark, alongside reduced risk of hypertension.

In inpatient studies, researchers controlled participants' diets initially and then allowed self-selection to examine the impact on sleep. They observed that while sleep efficiency was consistent during a short 4-hour window, variability in sleep duration occurred during a longer 9-hour opportunity, suggesting potential links between diet and sleep quality.

Dr. St-Onge emphasizes that if you consistently need naps despite getting sufficient sleep, it's crucial to investigate underlying issues affecting your nighttime sleep quality. She suggests examining factors contributing to poor sleep rather than relying on naps as a solution for daytime fatigue. This highlights the importance of addressing root causes of sleep problems.

A debate arose within Dr. St-Onge's lab regarding napping, with one advisor believing naps indicate sleep deprivation and are unhealthy. This sparked discussion referencing research from the Stanford Sleep Lab suggesting potential health benefits of short naps. The anecdote illustrates a common conflict between restrictive views on sleep and scientific evidence supporting strategic napping.

A recent study published in Nature revealed that the optimal sleep duration for aging, across various organs, falls within a range of 6.5 to 7.8 hours. The research also indicated slight differences between men and women, with women generally requiring slightly longer sleep durations for optimal organ health. This challenges the prescriptive '6-8 hours' guideline often promoted.

Women tend to sleep longer than men but frequently report poorer sleep quality and experience more difficulties like insomnia, trouble falling asleep, or maintaining sleep. This discrepancy suggests that while women may spend more time in bed, their sleep is often less restorative compared to men, highlighting a need for further research into the physiological factors involved.

A 2006 Nurses' Health Study tracked nurses over a 14-year period, revealing that those consistently sleeping only 5-6 hours per night experienced significantly higher rates of weight gain compared to those who slept 7-8 hours nightly. This highlights the long-term impact of insufficient sleep on metabolic health.

Dr. St-Onge explains that many significant scientific discoveries arise unexpectedly, often when researchers observe unforeseen effects in study subjects. These observations can lead to entirely new lines of inquiry beyond the initial research question, highlighting how unexpected benefits like improved sleep or skin health can spark further investigation.

A study investigated a coffee beverage enriched with mannan oligosaccharides, a long word derived from spent coffee grounds. The research found that this beverage led to a statistically significant greater loss of adipose fat tissue in overweight men compared to a placebo beverage – but only in men; the effect was not observed in women.

Dr. St-Onge differentiates between structural/functional claims (like calcium for bone health) and health claims (like fiber reducing cholesterol). Health claims require approval and are often seen on food packaging, while functional foods offer benefits beyond basic nutrition – exemplified by her earlier research into kefir.

Dr. St-Onge recounts how a graduate student, prompted by an advertisement from the McCormick company offering donated spices for research, chose to investigate ginger's potential impact on energy expenditure (thermic effect of food). This demonstrates a unique funding model and highlights the exploration of herbs and spices beyond their common culinary uses.

Dr. Marie-Pierre St-Onge’s research is unique because she leads one of the few laboratories globally that investigates the bidirectional relationship between sleep and food intake. This means her lab examines how sleep impacts eating habits, as well as how diet affects sleep quality, providing a more comprehensive understanding of their interconnectedness.

Studies have revealed that even modest sleep deprivation influences hunger hormones differently between genders. In men, it tends to increase the hormones driving appetite, whereas in women, it reduces naturally produced GLP peptides, which typically suppress feelings of hunger and promote satiety.

The speaker describes a cultural phenomenon in Argentina where people frequently eat very late at night (around 9 or 10 p.m.) and remain active until early the next morning, often into their 70s and 80s. This highlights how cultural norms can influence eating patterns and potentially impact health outcomes, even if those outcomes aren't necessarily positive.

Research by Marta Garaulet in Spain has demonstrated that participants in weight loss programs who consume their largest meal earlier in the day, specifically at lunch, tend to experience better weight loss results compared to those who eat later. This finding suggests a potential link between meal timing and metabolic health, even within cultures where late-night eating is common.

Alan Aragon's expertise in nutrition reassured the speaker that current recommendations regarding protein intake are often overemphasized. While striving for high-quality protein is beneficial, most individuals can achieve adequate muscle protein synthesis with just two meals and a potential snack, challenging the notion of needing to force late-night meals or early breakfasts.

Dr. St-Onge's PhD dissertation focused on medium-chain triglycerides (MCTs), which are processed differently by the body compared to long-chain triglycerides. MCTs travel directly to the liver for metabolism, leading to a higher thermic effect of food – meaning the body burns slightly more calories processing them. Her research involved purified MCT oil combined with flaxseed oil and plant sterols to study its impact on energy expenditure.

Dr. St-Onge recounts a piece of advice she received upon moving to the US, which was to avoid bagged bread from grocery stores and instead purchase freshly baked bread from bakeries. She explains that bagged bread often contains numerous additives and excessive sugar compared to bakery-fresh options, highlighting a difference in food formulation practices between countries.

Dr. St-Onge observed that yogurt purchased in the US tasted significantly sweeter than similar brands she consumed in Canada, despite having the same name and ingredients list. This observation led her to believe that food formulations are adapted to suit the preferences of different populations, with US yogurts being formulated to be sweeter.

Dr. St-Onge mentions the increasing popularity of GLP-1 receptor agonists like Wegovy and Ozempic, noting that many individuals are finding it easier to lose weight due to a reduction in appetite. She acknowledges she hasn't personally tried these medications but observes their impact on weight management.

Dr. St-Onge discusses a societal resistance to healthy eating habits, where individuals who prioritize their health through mindful food choices or limiting certain foods (like alcohol) may face social scrutiny and be perceived as restrictive. She contrasts this with the prevalence of unhealthy food conventions in the US, such as consuming hot dogs at baseball games.

The discussion highlights a difficulty in publishing negative or null results when research is funded by companies seeking to promote their products. There's concern that this funding structure can create pressure to find positive outcomes, potentially skewing the interpretation of data and limiting transparency. The speaker notes it 'doesn’t compute' when these challenges arise.

Dr. St-Onge expresses a clear preference for research funding from the National Institutes of Health (NIH) or the United States Department of Agriculture (USDA). She argues that these governmental sources are less likely to introduce bias compared to industry funding, allowing for more objective and reliable results in nutrition studies. The speaker specifically states she 'could imagine a world where you wouldn't need the money from companies.'

Jay Bhattacharya’s perspective, referenced in the discussion, emphasizes the critical importance of publishing negative or null results in scientific research. These findings can steer individuals away from ineffective practices and prevent wasted resources. The speaker highlights that these results are often suppressed due to publication pressures.

The conversation underscores the necessity for rigorous statistical analysis and training within research labs. Mentors should guide students to accurately interpret data, recognizing that seemingly different numerical values may not be statistically significant due to factors like standard deviation. This ensures a more objective assessment of results and prevents misinterpretations.