"Which Foods Increase Happiness?"
Thousands of papers have been published on the important topic
of what determines people’s happiness and psychological health,
but what about the potential influence
of the different kinds of foods that people eat?
The rising prevalence of mental ill health
is causing a considerable burden,
and so inexpensive and effective strategies are required
to improve the psychological well-being of our population.
And now we have a growing body of literature
suggesting that dietary intake may have the potential
to influence psychological well-being.
Dietary intake of what?
Well, given the strong evidence base for the
health benefits of fruits and vegetables,
researchers started there.
Cross-sectional studies from all over the world
support this relationship between
happiness and fruit and vegetable intake.
Those eating fruits and vegetables each day
had a higher likelihood of being classified as “very happy",
suggesting a strong and positive correlation
between fruit and vegetable consumption and happiness.
Perhaps feelings of optimism, too.
The largest such study was done in Great Britain,
where a dose–response relationship was found
between daily servings of fruits and vegetables
and both life satisfaction and happiness,
meaning more fruits and veggies meant more happiness.
People who got up to seven or eight servings a day
reported the highest life satisfaction and happiness.
And these associations remained significant
even after controlling for factors such as income
and illness and exercise, smoking and body weight,
suggesting fruit and vegetable consumption
wasn’t just acting as a marker for other healthy behaviors.
But how could eating plants improve happiness on their own?
Well, many fruits and veggies contain higher levels of vitamin C,
which is a co-factor in the production of dopamine,
the “zest for life” neurotransmitter.
And the antioxidants reduce inflammation,
which may lead to higher levels of eudaemonic well-being.
Aristotle's notion of eudaemonia,
described as the highest of all human goods,
the realization of one's true potential,
which was the aim of this study.
They wanted to know whether eating fruit and vegetables
was associated with other markers of well-being
beyond happiness and life satisfaction,
like greater eudaemonic well-being –
a state of flourishing characterized by feelings
of engagement, meaning, and purpose in life.
So a sample of about 400 young adults were followed
for about two weeks and indeed young adults who ate
more fruit and veggies reported higher average eudaemonic well-being,
more intense feelings of curiosity, and greater creativity.
And they could follow this on a day by day basis—
greater well-being on the days they ate healthier.
These findings suggest that fruit and vegetable intake is related
to other aspects of human flourishing,
beyond just feeling happy.
Not so fast, though.
Instead of eating good food leading to a good mood,
maybe the good mood led to eating good food.
Experimentally, if you put people in a good mood,
they rate healthy foods like apples
higher than indulgent foods like candy bars.
Given a choice between M&M’s and grapes,
individuals in a positive mood
were more likely to choose the grapes.
The results of these studies
lend support to a growing body of research
that suggests that positive mood facilitates resistance to temptation.
Who needs comfort food when you’re already comforted?
It’s like which came first, the chicken or the egg?
Yes, eating eggs can increase our likelihood of chronic disease,
but maybe chronic disease also increases our likelihood
of eating unhealthy foods.
Which came first, the mood or the food?
What we need is a study like this,
but instead of looking at well-being and diet
on the same day,
you see if there’s a correlation between what you eat today,
and how you feel tomorrow.
But we didn’t have a study like that…
until now.
They found the same strong relationships
between daily positive mood and fruit and vegetable consumption,
but lagged analyses showed that fruit and vegetable consumption
predicted improvements in positive mood the next day,
not vice versa.
On days when people ate more fruits and vegetables,
they reported feeling calmer, happier, and more energetic
than they normally do,
and they also felt more positive the next day.
So, eating fruit and vegetables really may promote emotional well-being.
Look, single bouts of exercise can elevate one’s mood,
why not the same thing with healthy food?
How many fruits and vegetables?
Seems we need to consume approximately 7.2 daily servings
of fruit or 8.2 servings of vegetables to notice a meaningful change.