This article is a summary of this published research: Chrono-nutrition – an emerging, modifiable risk factor for chronic disease?
Our body has internal clocks called circadian rhythms that regulate our daily biological processes. Changes in our eating and sleeping patterns, such as during the COVID-19 pandemic, can have metabolic effects. Chrono-nutrition is a new field of research that explores the relationship between our biological rhythms and nutrition. This review examines global trends in the timing of energy intake and its potential association with obesity.
The timing of energy intake varies greatly among different countries and regions. Some people consume more energy earlier in the day, while others eat more in the evening. Several studies suggest a positive link between evening energy intake and obesity. However, the evidence regarding this association is inconsistent.
Our biological clocks, located in the brain and various tissues, regulate our bodily functions. Feeding behavior also follows a daily pattern, with rodents consuming more calories during their active phase. Studies have shown that consuming calories during the resting phase leads to weight gain. Similar findings have been observed in humans, with meal timing influencing metabolic responses and weight loss.
Regulating blood glucose and lipid levels is crucial for health. Postprandial glucose and triglyceride responses can be influenced by the timing and composition of meals. Exaggerated post-meal glucose and lipid levels are associated with cardiometabolic diseases.
In conclusion, chrono-nutrition investigates how the timing of food intake impacts our health. Understanding the connection between our biological rhythms and nutrition can have important implications for managing weight and preventing chronic diseases.
How Restful Nights Impact Weight and Health
Getting enough sleep at night and being awake during the day is an important part of our body’s natural rhythm. Sleep is crucial for our overall health and well-being as it affects various aspects of our body’s functioning, including cognitive performance, metabolism, appetite regulation, immune function, and hormone regulation. When our sleep patterns are disrupted, it can lead to metabolic and hormonal changes, such as insulin resistance and glucose intolerance.
Research has shown that insufficient sleep duration is associated with a higher risk of obesity and cardiometabolic diseases. The relationship between sleep and health follows a “reverse J-shaped” curve, meaning that both too little and too much sleep can be detrimental. The optimal amount of sleep for most individuals is around 7-8 hours per night.
In a study funded by the British Nutrition Foundation, researchers investigated the effects of sleep duration and quality on energy balance, dietary intake, and cardiometabolic risk factors. Their findings revealed that partial sleep deprivation resulted in increased energy intake without a corresponding increase in energy expenditure, leading to a positive energy balance and potential weight gain. They also found that sleep quality is linked to lipid metabolism, and extending sleep duration can be a feasible intervention for habitual short sleepers.
Although the impact of sleep on dietary outcomes may seem small in the short term, it can accumulate over time and contribute to an increased risk of obesity and related health problems. Studies have shown that sleep extension in individuals with short sleep duration can have positive effects on appetite regulation, glucose metabolism, body weight, and dietary intake. However, more well-designed and longer-term studies are needed to fully understand the role of sleep in tackling the obesity crisis and promoting better health.
Exploring the Role of Morning Meals in Weight Loss
One particular area of research in chrono-nutrition focuses on the role of breakfast, which is the first meal of the day. In the UK, a significant portion of the population tends to skip breakfast, although this trend may have changed recently due to the pandemic. Consuming a meal early in the day after an overnight fast is thought to play a crucial role in regulating our internal biological rhythms and controlling glucose levels. However, the impact of breakfast within the context of circadian eating patterns is complex.
Observational studies generally suggest that eating breakfast may have a protective effect against weight gain. However, controlled interventions that have investigated the effects of skipping breakfast on energy balance have not supported the hypothesis that skipping breakfast leads to better weight control.
The Big Breakfast Study, funded by the Medical Research Council, aims to shed light on the underlying mechanisms of how a larger morning meal may enhance weight loss. This study examines the behavioral and physiological adaptations related to energy expenditure and circadian biology. By conducting a randomized controlled trial comparing morning-loaded and evening-loaded weight loss diets over a 4-week period, the study will provide valuable insights into the mealtime-dependent metabolic processes and their impact on overweight and obese individuals.
Exploring the Effects of Fasting and Time-Restricted Eating on Health and Weight Management
Our biological clock requires periods of fasting to reset itself, and recent approaches like intermittent fasting and time-restricted eating have gained popularity as potential methods for weight management and improving metabolic health. Intermittent fasting has also been linked to healthy aging. The three most studied intermittent fasting regimens in humans are alternate-day fasting, 5:2 intermittent fasting (two fasting days per week), and daily time-restricted feeding.
Time-restricted feeding (TRF) or time-restricted eating (TRE) is a form of intermittent fasting that aligns with our circadian rhythm. However, studies on TRF in humans have been limited to pilot or feasibility studies with different protocols and participant characteristics, making it challenging to apply the findings to real-life situations.
In this Virtual Issue, Dr. Clayton, a recipient of a British Nutrition Foundation Drummond Pump Priming award, will conduct a randomized crossover study exploring the effects of extended morning fasting or evening fasting on energy balance, metabolic health markers (such as blood sugar control), and participants’ subjective experiences. The primary hypothesis is that evening fasting will reduce energy intake, improve blood sugar control and appetite compared to morning fasting. This study focuses on lean, healthy individuals, contributing to our understanding of time-restricted eating for weight management in this population.
Another study by Lynch et al. in this Virtual Issue examines the impact of early and late time-restricted feeding on established risk factors for type 2 diabetes in a 10-week intervention trial. The main hypothesis is that daily time-restricted feeding will decrease food intake, body weight, and adiposity while improving markers of metabolic disease. The study also explores whether early time-restricted feeding leads to more significant metabolic changes compared to late time-restricted feeding. Additionally, Lynch et al. will investigate the practical implications of eating earlier in the day, including its effects on social interactions and food preferences.
Both studies by Clayton et al. and Lynch et al. will provide valuable insights into the optimal timing of food intake—whether earlier or later in the day—for weight management and the potential role of chrono-nutrition in preventing chronic diseases.
The Impact of Shift Work and Circadian Rhythms on Nutrition
Recent attention has focused on the potential role of chrono-nutrition in chronic diseases. Modern lifestyles, including shift work, exposure to artificial light for extended periods, and irregular eating patterns, can disrupt our natural circadian system. Research indicates that shift workers, especially those working at night, are at a higher risk of developing chronic diseases like type 2 diabetes and cardiometabolic disorders.
Understanding the relationship between working hours and diet is still an area of ongoing research. Shift workers represent a significant portion of the workforce, with 15% of the UK population working in shifts and 12% working at night. The review by Gibson in this Virtual Issue provides insights into the current state of research and future directions in the field of working hours and nutrition.
However, chrono-nutrition is not only relevant to shift workers but also to the general population. Circadian patterns change throughout our lives, with the amplitude reducing and the timing becoming more variable as we age. Adolescents and older adults are particularly susceptible to sleep disorders due to changes in their circadian rhythms. Sleeping disorders like delayed sleep phase disorder in adolescents and shift work disorder and jet lag disorder in older adults can disrupt their health. Chrono-nutrition considerations may also be important for those with age-related disorders such as dementia.
While the importance of chrono-nutrition is evident, further research is needed to develop appropriate public health recommendations for different age groups and individuals with specific lifestyle patterns.
Understanding the Impact of Chrono-nutrition
Public health implications: What about chrono-type?
Understanding how different aspects of chrono-nutrition, such as fasting, sleep, working hours, and nutrient distribution, influence our health can have a significant impact on improving the well-being of many people. When addressing chrono-nutrition in the context of managing obesity and related disorders, it is crucial to consider an individual’s chrono-type, which refers to their preferred time of day for activities and rest.
Studies have shown that individuals with a later chrono-type, or evening-type, tend to have unhealthy eating habits associated with obesity. They consume more of their energy intake later in the day, which increases the risk of overweight/obesity. On the other hand, individuals with a morning chrono-type tend to engage in more physical activity in the morning and have healthier habits like regular breakfast consumption and more meals throughout the day.
It is important to note that chrono-type is a relatively stable trait, but it can have implications for our health. Research has also highlighted the potential future risk of circadian misalignment among young adults if the mismatch between sleep-wake behavior and circadian preference persists.
Considering chrono-type in both observational and intervention studies can provide valuable insights into the impact of chrono-nutrition on real-life health outcomes. This knowledge can contribute to developing effective public health strategies for promoting healthier eating patterns and reducing the risk of chronic diseases.
Keywords: chrono-nutrition, chrono-type, obesity, eating habits, circadian misalignment, public health.
In conclusion
In conclusion, chrono-nutrition is an emerging field of study that has important implications for public health. Our modern lifestyle and constant availability of resources have disrupted our natural circadian rhythms, and it is crucial to develop interventions to counteract these effects.
Intervention studies on chrono-nutrition should be conducted in real-life settings, considering the day-to-day and seasonal variability, as well as individual differences in chrono-type. Personalized approaches will be necessary as there is no one-size-fits-all solution in chrono-nutrition.
By considering chrono-nutrition, we can gather valuable evidence from real-life studies to better manage chronic diseases like obesity and cardiometabolic disorders. Effective interventions can then be translated into public health recommendations. Already, organizations like the American Heart Association have begun incorporating chrono-nutrition principles into their guidelines, such as emphasizing a more regular energy intake throughout the day with a greater proportion of calories consumed earlier.
The findings from the studies discussed in this Virtual Issue will contribute to future recommendations. It is important for public health guidelines to address not only a healthy diet and physical activity but also sleep patterns and chrono-type. To truly promote a healthy lifestyle, we need to consider not only what we eat but also when and how we sleep.
