A healthy diet is fundamental to overall wellbeing, but recent research suggests that when we eat is just as important as what we eat. In this two-part series, we explore Chrononutrition – the study of how meal timing affects health and metabolism. We’ll first look at Intermittent Fasting (IF), a popular but sometimes controversial dietary approach gaining traction in the fitness and wellness communities.

Disrupting our eating rhythm can have short- and long-term effects

Chrononutrition is rooted in the body’s circadian system, which regulates biological functions like metabolism, hunger and body temperature. Our traditional eating patterns – breakfast, lunch, and dinner – train the body to follow a fuel-refuel-fuel-refuel rhythm. Disrupting this rhythm can have both short- and long-term consequences, including dehydration, blood sugar fluctuations, and even weight gain.

As scientists have explored the relationship between eating patterns and metabolism, they have developed various meal timing strategies tailored to different lifestyles and health goals. One of the most widely recognised is Intermittent Fasting, which involves restricting food intake to a set window each day. IF has been praised by advocates who claim it can help you to look better, live longer, improve your energy and mood, and support weight management.

While some of these claims may be exaggerated, scientific research supports the idea that meal timing significantly influences health. Studies show that poor food choices at night are linked to issues like malnutrition, weight gain, depression, and heart disease. On the other hand, consuming the first meal of the day at an appropriate time can boost mental health, sustain energy levels, and enhance daily performance.
A major new study has confirmed that IF can improve health in real-world conditions. The study found that a 10-hour eating window was both manageable and beneficial, leading to improved mood, energy levels, and hunger control.

For the first time, researchers also discovered that consistency is key. Participants who followed time-restricted eating every day experienced significantly greater health benefits than those who were inconsistent.

Dr. Sarah Berry, chief scientist at ZOE and a researcher at King’s College London, explained that 37,545 people participated in the study via the ZOE Health app. They ate normally for one week, then restricted their eating to a 10-hour window for two weeks. Over 36,000 participants chose to extend their participation, with 27,371 classified as highly engaged. Among these, 78% were female, with an average age of 60 and a BMI of 25.6. Interestingly, those with longer eating windows before the study saw the greatest health improvements.

We don’t need to be eating all the time

Dr. Kate Bermingham, also from King’s College and ZOE, emphasised the importance of meal timing. She said the study adds to growing evidence that when you eat matters just as much as what you eat. We don’t need to be eating all the time – many people feel fuller and even lose weight when they limit their food intake to a 10-hour window.

Stay tuned for part two, where we explore practical ways to implement Intermittent Fasting and how to balance meal timing with nutritional quality for optimal health.