In particular, the study showed that a diet rich in fruit and vegetables and regularly moving makes people happy, rather than the other way around – that happier people may be more likely to choose health promoting behaviours. The reason all comes down to people’s ability to delay gratification.

“The consumption of fruits and vegetables and sports activity are often undertaken as investments in a healthier future rather than because they bring immediate pleasure,” researchers write. When we purposely decide to push back our gratification, by reaching for vegetables or scheduling in a run, we can change the neural pathways in our brain. Specifically, we dull the limbic system (associated with survival and our ‘fight or flight’ mode). “The ability to delay gratification is strongly correlated with brain function… [therefore] healthy behaviours have a significant impact on the life-satisfaction,” say the paper’s authors.

Fruit, vegetables and exercise really do make you feel better, according to science