The study is one of the first major scientific attempts to explore psychological well-being beyond the traditional finding that fruit and vegetables can reduce risk of cancer and heart attacks, researchers said.
Happiness benefits were detected for each extra daily portion of fruit and vegetables up to 8 portions per day.
Researchers found that people who changed from almost no fruit and veg to eight portions of fruit and veg a day would experience an increase in life satisfaction equivalent to moving from unemployment to employment.
The well-being improvements occurred within 24 months, researchers said.
“Eating fruit and vegetables apparently boosts our happiness far more quickly than it improves human health,” said Andrew Oswald from University of Warwick in the UK.
“People’s motivation to eat healthy food is weakened by the fact that physical-health benefits, such as protecting against cancer, accrue decades later. However, well-being improvements from increased consumption of fruit and vegetables are closer to immediate,” said Mr. Oswald.
The study followed more than 12,000 randomly selected people. These subjects kept food diaries and had their psychological well-being measured.
Researchers found large positive psychological benefits within two years of an improved diet.
“Perhaps our results will be more effective than traditional messages in convincing people to have a healthy diet,” said Redzo Mujcic from University of Queensland in Australia.
“There is a psychological payoff now from fruit and vegetables — not just a lower health risk decades later,” said Mr. Mujcic.
The findings were published in the American Journal of Public Health.