University of Granada study links fruit at dinner with better night-time glucose control in obese adults

A fear-driven story has been circulating on social media, portraying the sugar in fruit as harmful and advising people to avoid fruit-particularly in the evening. However, a study suggests the opposite: eating fruit at dinner is linked with improved night-time glucose control in obese adults.

What the University of Granada study found about fruit at dinner

Led by the University of Granada and published in Clinical Nutrition, the research examined how the make-up of each main meal across the day relates to the subsequent glycaemic response in obese adults.

The university reported on Monday that breakfasts containing more fruit, dairy products, coffee or tea without added sugar, and protein were associated with lower subsequent glycaemic variability-considered beneficial for health. By contrast, lunches higher in carbohydrates were linked to higher subsequent glycaemic variability.

At dinner, higher fruit intake correlated with a better night-time glycaemic response. The reverse pattern was observed when dinners included alcoholic drinks, processed meats, and refined bread or refined pasta, which were associated with poorer night-time outcomes.

How the research tracked night-time glucose in obese adults

A key element of this work is its “exhaustive” real-world assessment of how the composition of each main meal is connected to the glycaemic response that follows.

To do this, participants wore a continuous glucose monitor for 14 days-a small sensor that measures blood glucose levels continuously.

Over the same period, dietary intake was recorded, with particular focus on breakfast, lunch, and dinner.

The researchers then linked each meal to its corresponding glycaemic response in participants’ everyday lives, outside controlled laboratory settings, providing a perspective that is more readily generalisable.

Social media claims about fruit sugar versus the evidence

Juan José Martín Olmedo, a researcher at the University of Granada and the study’s first author, and Lucas Jurado Fasoli, the senior author, emphasised that the findings reinforce the beneficial role of fruit, including at dinner.

"An alarmist narrative has spread on social media, demonising the sugar in fruit and discouraging its consumption, especially at night, but our data show precisely the opposite", he said.

"An alarmist narrative has spread on social media, demonising the sugar in fruit and discouraging its consumption, especially at night, but our data show precisely the opposite", he added.

Martín explained that, beyond sugar content, fibre and bioactive compounds generally support a better subsequent glycaemic response. He also noted that, in a population at high risk of type 2 diabetes, cutting out fruit due to unfounded fear "may even be counterproductive".