Chronobiology is a new buzz word in health and wellness. The term refers to the timing of our natural biorhythms, including our circadian rhythm, which help the body run efficiently. Erratic eating habits, especially late-night eating, and altered sleep schedules can throw our biorhythms out of sync. Even exposure to artificial light at night can affect our circadian rhythm. Epidemiological data suggests this has the potential to, amongst other things, increase our risk of developing gastrointestinal issues and type 2 diabetes (Canuto, Garcez & Olinto 2013, Vaughn, Rotolo & Roth 2014). Therefore, organizing the timings of our days correctly, including when we eat, is of huge interest to health geeks. Chrono-nutrition refers to coordinating food intake with the body’s daily rhythms and is increasingly gaining attention as more research emerges.
Front load your day
Our biorhythms affect food metabolism and energy balance. For example, one famous study showed participant’s blood glucose levels were 30-50 mg/dL higher in the afternoon and evening than the morning, terming the phenomenon ‘afternoon diabetes’ (Roberts 1964). Moreover, this same study found the blood sugar response to identical meals was more than 2-fold larger in the evening than in the morning. In terms of energy expenditure, another group of scientists found diet-induced thermogenesis (the amount of energy burned from eating a meal) was 31% lower after having an evening meal (Romon et al. 1993).
Despite consuming the same number of calories, it seems late eaters lose less weight than early eaters, have higher insulin and blood glucose levels, and a slower metabolism. This favours the idea of eating earlier in the day; the old saying ‘eat breakfast like a king, lunch like a prince and dinner like a pauper’ seems to have scientific backing.
Whilst many of us find ourselves too busy to eat a significant breakfast and often grab something light on the go, it’s time to start planning a proper breakfast. Try avocado and poached eggs on a slice of wholegrain bread, oatmeal with nuts and berries, or Greek yoghurt and trail mix. Eat smaller portions in the evening and experiment with light options for dinner, such as an omelette, or a veggie-based bowl.
Serve up when the sun’s out
A variety of enzymes involved in lipid and glucose metabolism are regulated according to circadian cycles; our bodies are used to sleeping at night, when melatonin is produced, and being active and eating during the day, when cortisol production is highest. Any disruption to this rhythm can throw the body’s rhythm out of balance and increase the risk of disease. Night shift-workers, for example, are at an increased risk of weight gain, high blood pressure, high cholesterol, high triglycerides, atherosclerosis and heart attack (McHill et al. 2014, Sun et al. 2017, Farha & Alefishat 2018).
Blue light is the most important signal for circadian synchronization, and this peaks at midday when the sun is out. Therefore, if possible, try to eat most of your food during daylight hours, and have a 12-15 hour fasting window overnight. Regardless of your schedule, try to get about eight hours of sleep per day; even better if it’s around the same time. Create a calm and dark space where you can wind down and settle into a restful sleep. Stay away from electronic devices containing LEDs as much as possible at night time; the light they admit affects chronobiology more than ANY drug currently on the market! Epidemiological evidence suggests using these devices at night leads to circadian phase delays, melatonin suppression and impairs sleep quality (Falbe et al. 2015).
When we eat may be just as important as what we eat. Eating more food later in the day and having an unnatural sleep/wake cycle may increase an individual’s risk of weight gain and metabolic disease. Good news is it’s easy to make small, yet significant shifts to our day, to help improve our health; for example, by getting regular sleep.