Why Scientists Say We’ve Been Eating at the Wrong Time of Day

“Have breakfast like a king, lunch like a prince and dinner like a pauper.”
It’s a phrase my Spanish friend Javier Hirschfeld grew up hearing and one that perfectly captures Spain’s long‑standing approach to food. In much of Spain, lunch is the day’s biggest meal, while dinner is often a light bite or skipped entirely.

Across the UK and US, however, the pattern is reversed: a quick lunch followed by a heavy evening meal. But emerging research suggests we may have been doing it backwards all along. A growing scientific field known as chrononutrition argues that healthy eating isn’t just about what we eat but when we eat it.

Chrononutrition studies how our internal body clock, or circadian rhythm, shapes hunger, digestion and metabolism. And the findings are striking. In one small controlled trial, 32 healthy women ate identical meals for two weeks. Those who ate lunch later in the day had poorer blood‑sugar control and burned fewer carbohydrates. Other studies echo the same conclusion: timing matters far more than we once believed.

Why does eating the same food at different times produce such different results? When I put this question to Frank Scheer, a professor of medicine and neuroscientist at Brigham and Women’s Hospital in Boston, he explained that “we’re not the same person in the morning and the evening from a biological point of view.”

Our body clock regulates almost every aspect of our physiology including how efficiently we metabolise food.

The science suggests that front‑loading calories earlier in the day may help reduce obesity risk, improve cardiovascular health and support better metabolic function. In other words, Javier’s childhood mantra may have been right all along.