Sorry, eating vegetables probably won’t make you any happier

    12 July 2016

    A higher intake of fruit and vegetables is linked to greater happiness, according to a study published in the American Journal of Public Health.

    But claims that eating more fruit and veg will actually make you happier are not supported by the evidence (see our expert verdict below).

    Researchers from the University of Warwick studied the food diaries of over 12,000 volunteers over a period of two years. During this time the participants’ ‘psychological well-being’ was measured.

    They found an increase in happiness for every extra daily portion of fruit and vegetables we eat, up to eight portions a day. The improvements occurred within two years, which researchers suggest is more immediate than any physical health benefits.

    They found that those who went from eating almost no fruit and vegetables to eight portions a day experienced the greatest increase in life satisfaction, equivalent to that of an unemployed person finding a job.

    Changes in happiness and life satisfaction were adjusted to take into account changing incomes and other personal circumstances.

    Professor Andrew Oswald, the study’s lead author, said: ‘Eating fruit and vegetables apparently boosts our happiness far more quickly than it improves human health.

    ‘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.’

    Dr Redzo Mujcic, who also worked on the study, said: ‘Perhaps our results will be more effective than traditional messages in convincing people to have a healthy diet.

    ‘There is a psychological payoff now from fruit and vegetables — not just a lower health risk decades later.’

    Instant analysis
    Food diaries during 2007, 2009 and 2013, taken from the Household, Income and Labour Dynamics in Australia study, were examined alongside questionnaire returns. Researchers cited a few small studies suggesting that high fruit and vegetable consumption was linked to wellbeing.

    The questions were simple enough: ‘How many days of the week do you consume fruit?’ and ‘How many days of the week do you consume vegetables?’ This was then stratified according to quantity. The data suggested the average daily amount was 3.84 servings, give or take two — a wide variation. Subsequently, each subject was asked how satisfied with their life they were and how often they were happy.

    The study suggested that the difference between zero fruit and veg and the maximum amount was about 0.24 points in life satisfaction and that this was akin to being employed after unemployment, or half the effect of marital separation. 

    Attempts to adjust for confounders were limited. Researchers examined whole household incomes, marital status and number of children, but didn’t examine relationship status, or even, say, sexuality or celibacy. Participants were asked if they never ate red meat or fish and if they had a regular breakfast, drank low-fat milk or avoided fatty foods. This is an incomplete approach to eating habits.

    The paper alluded to a chicken vs egg explanation regarding fruit and veg consumption — did people consume more of it as they were more affluent, and therefore would score better on wellbeing? Did people eat less healthily as they were unhappy? I would agree with the latter. When I’m feeling miserable, I order a takeaway. Ultimately the paper offered no explanation or discussion on this area.  

    I suspect that fruit and vegetable consumption is linked to wellbeing, and goes up when we feel better. However, contrary to the paper’s suggestion, eating more fruit and vegetables does not necessarily make you a happier person. These were two outcomes that were juxtaposed and a trend observed. There are so many other factors involved that I am not sure where to even start.

    Needless to say, I shall not be prescribing kale for depression, or asking patients if the real culprit for their illness might be a reduction in their veg intake.
    Research score: 1/5