"Is It Better to Advise More Plants or Less Junk?"
The World Health Organization has estimated that over a million deaths
worldwide are linked to low fruit and vegetable consumption.
What can be done about it? There's always appealing to vanity.
A daily smoothie can give you both a golden glow and a rosy glow,
both of which have been shown to enhance one's healthy appearance
in Caucasian, Asian, and African skin tones.
But what about giving it away for free?
A free school fruit scheme was introduced in Norway
for grades 1 through 10.
Fruit consumption is so powerfully beneficial
that if kids just ended up eating 2.5 grams more fruit a day,
the program would pay for itself in terms of saving the country money.
That's the weight of half of a single grape.
However, that's assuming that miniscule increased fruit consumption
would be retained throughout life.
It certainly seemed to work while the program was going on,
with a large increase in pupils eating fruit,
but what about a year after the free fruit ended?
They were still eating more fruit. They were hooked!
And then, three years later, same thing: eating about a third of a serving more
three years later, considerably more, if sustained,
than necessary for the free fruit program to pay for itself.
And there were some happy side effects.
There was a positive spillover effect where not only
were the kids eating more fruit; their parents started eating more, too.
And although the intention of these programs was not to reduce
unhealthy snack intake, that's exactly what appeared to happen—
the fruit replaced some of the junk.
Increasing healthy choices
to crowd out the unhealthy ones may be more effective
than just telling kids not to eat junk, which could actually backfire.
When you tell kids not to eat something, they may start to want it even more.
Which do you think worked better,
telling families to increase plants or decrease junk?
Families were randomly assigned to one of two groups:
encouragement to get at least two servings of fruits and veggies a day,
with no mention of decreasing junk;
and the other group, who were encouraged to bring their junk food
intake to less than 10 servings a week but with no mention of fruits and veggies.
What do you think happened?
The Increase Fruit and Vegetable intervention just naturally reduced
their high fat and sugar intake,
whereas those told to just Decrease Fat and Sugar cut back on junk,
didn't magically start eating more fruits and vegetables.
This crowding out effect may not work on adults, though.
In a cross-section of more than a 1,000 adults in Los Angeles and Louisiana,
those that ate five or more servings of fruits and veggies a day
did not consume significantly less alcohol, soda, candy, cookies, and chips.
This finding suggests that unless the excessive consumption of junk
is curtailed, other interventions may have a limited impact.
It may be politically more expedient to promote an increase in consumption
of healthy items rather than a decrease in consumption of unhealthy items,
but it may be far less effective.
In most public health campaigns, the message is direct and explicit:
don't smoke, don't drink, don't take drugs.
In contrast, food campaigns have focused on "eat healthy foods" than "cut out the crap."
Explicit messages against junk are rare.
In the U.S., if just half of the population were to increase
fruit and vegetable consumption by one serving each per day,
an estimated 20,000 cancer cases might be avoided each year.
20,000 people who would not have gotten cancer
had they eaten their fruits and veggies.
The USDA recommends half our plate be filled
with colorful fruits and vegetables,
but less than 10% of Americans hit the recommended daily target.
Given this sorry state of affairs,
should we even bother telling people to strive for 5 a day
or might just saying "get one more serving than you usually do"
end up working better?
The researchers thought that the more realistic "just 1 more" goal
would be more effective than the very ambitious "5 a day" goal,
but they were wrong.
Those told to eat one more for a week, ate about one more,
and those that were told to eat five ate five, but here's the critical piece.
A week later, a week after the experiment was over,
the group that was told to eat 5 a day was still eating about a serving more,
whereas the eat one more group went back to their miserable baseline.
So more ambitious eating goals may be more motivating.
Perhaps, this is why in the US "5 a day" was replaced
with a recommended daily consumption of 7—13 servings of fruits and vegetables.
But if the recommendation is too challenging, people may just give up.
So instead of just sticking with the science,
policy makers need to ask themselves questions
like how many servings are regarded as threatening?