When you eat might be just as important as what you eat. Here’s how to time it right for you

‘Breakfast like a king, lunch like a prince, dinner like a pauper,’ goes the adage – and it turns out there’s some truth in it. In information and conversations about nutrition, the emphasis is often on what we put on our plates. But an emerging field of research suggests that when we eat is just as important. Called circadian eating, the concept is rooted in the idea of eating in line with your body’s circadian rhythm – your internal clock.

‘Without any external stimulus, we have a rhythm that determines our sleeping and waking. This is our circadian rhythm,’ says registered dietitian Helen Phadnis, adding that this internal clock is also impacted by external factors: ‘Sunlight, temperature, exercise and social interactions can all contribute to how it functions.’ The most obvious example of this at play is with jet lag. When moving across time zones, the brain finds it hard to sleep as the circadian rhythm is still synced to the original time. While the circadian rhythm’s primary function is to control when you’re awake and asleep, it subsequently affects lots of aspects of health and wellbeing, such as energy levels, focus and productivity throughout the day – and eating patterns.

Thanks to this internal clock and the pattern of waking and sleeping, the body doesn’t function identically throughout any one 24-hour period. ‘The metabolism is profoundly different during the day and during the night,’ writes Russell Foster, a professor of circadian neuroscience and author of Life Time: The New Science of the Body Clock, and How It Can Revolutionize Your Sleep and Health. ‘As day-active animals, we consume calories during the day and then we burn them. At night, we use stored calories (from glucose in liver and fat, for example) while asleep, to keep our metabolism going.’ He uses the example of exercise to illustrate this: ‘If you work out in the morning, before breakfast, you’re using your stores, while if you work out later in the day, you’re using the food that you’ve eaten that day.’