FOOD FOR THOUGHT

While the nutritional content of your daily fare matters, so does when you choose to chow down. It’s time to get to grips with chrononutrition: the dietary difference-maker to your body’s metabolic health that you might be overlooking

Should you be keeping your mealtimes consistent?

Whether it’s your morning vinyasa practice, your 11am coffee or your lavender-scented, screen-free reading window between 10.30pm and 11pm, humans are creatures of habit. The attraction to routine isn’t surprising, and a key element of a daily routine is, of course, when you eat. The study of meal timing and its effect on health – aka chrononutrition – considers three key aspects of your eating patterns: meal consistency (skip breakfast?), meal frequency (do you eat little and often or have bigger main meals?) and clock time (when are your first and last calories consumed?).

Health researchers are increasingly interested in chrononutrition because food is a ‘zeitgeber’. That is – aside from another win for German linguistic efficiency – something with the ability to impact your circadian rhythms (aka your internal body clock) and, consequently, your metabolic health – as reflected by your levels of blood sugar, cholesterol, blood pressure and body fat. Research suggests that having irregular eating patterns and distributing most of the day’s calories close to the body’s ‘biological night-time’ is associated with increased body fat and a higher risk of metabolic syndrome – a combination of high blood pressure, raised blood glucose and cholesterol.

Such eating habits are more common than you might think. In one 2015 study, researchers monitored meal timing in healthy adults over three weeks using a smartphone app. Rather than three daily meals, they discovered erratic eating patterns and significant variation between weekdays and weekends, with participants tending to eat later on the latter. Researchers concluded this shift to a longer, later eating window on weekend days was the metabolic equivalent of travelling across time zones, a phenomenon they dubbed ‘metabolic jet lag’ – which could, over time, have repercussions for your metabolic health.

Although no relationship was found between body mass index (BMI) and a longer eating window in this study, a larger Spanish study found a positive relationship between this so-called jet lag and BMI in young adults. A year later, in 2016, a separate study, conducted on women of a healthy weight, found that a regular meal pattern (three meals, three snacks) resulted in better insulin sensitivity and less hunger when compared with an irregular meal pattern (varying between three and nine meals) comprising the same total amount of calories. The impact of meal timing on metabolic health may also explain why shift workers disproportionately develop metabolic syndrome, even though research suggests they don’t eat more calories.

If you do relate to the symptoms of metabolic jet lag, there are a couple of ways you can resync. On weekends, you can make an effort to mimic your weekday mealtimes, or you can still have later meals at weekends, but reduce your overall eating window, as research suggests reducing from a 15 to 10-hour period limits metabolic jet lag while improving energy levels and sleep. And for shift workers: consume the majority of your calories in the earlier part of your wake cycle and, if you need to snack during the night, opt for high-protein, high-fibre morsels. Now’s the time.