Stop the decline in fruit and vegetable intake among children

Personally, I have no trouble getting my two to chow down on plenty of fruit and vegetables. In fact, around 60% of their diets are fruit.

Well, my two adopted orangutans obviously have more discerning tastes than their young human counterparts.

However, if it makes you feel better their table manners are worse – they also use their feet for eating – so you can’t have everything.

Fruit and vegetable intake today (among humans)

Worldwide consumption of fruit and vegetables is way too low.

Most dietary guidelines suggest 5+ servings per day (2 fruit and 3 vegetable servings). However, almost all national surveys report intakes far below recommended levels.

Earlier this week a study reported that only 1 in 10 adult Americans met fruit and vegetable intake recommendations.

And children are faring no better with a European study reporting less than one in ten children consume 5 servings of fruit and vegetables per day.

The New Zealand Health Survey results are slightly better for fruit intake with 70% of children aged 2-14 years consuming 2+ serves per day, but only 42% reported eating 3+ serves of vegetables.
 
Evidence-based strategies to increase consumption are limited

A 2019 Cochrance review of 63 intervention studies designed to increase consumption of fruit and vegetables among children under 5 years found very small and somewhat disappointing increases in intake.

The authors also note the lack of high quality studies in the area.

Hence our review of a more recent well-designed trial by Professor Barbara Rolls (an academic celebrity in the world of children's eating behaviour) and team at Penn State University.

Here they set out to investigate two strategies aimed at increasing vegetable and fruit intake among children: adding or substituting.
 
In their previous work, Rolls and colleagues showed when portion size is increased – kids eat more. Would this hold true for fruit and vegetables?

They were also interested to see if substituting fruit and vegetables for other foods would increase intakes even more than just adding extra. 
 
This crossover study among 53 children aged 3 to 5 years had three treatment arms: Control, Addition and Substitution.

The Control arm incorporated typical portions of food:

Both the Addition and Substitution treatments incorporated 50% more vegetables and fruit:

In the Addition treatment the fruit and vegetables were simply added, whereas in the Substitution they replaced other foods of the same weight.

The researchers provided all meals and snacks for five days. Children ate breakfast, lunch, an afternoon snack, and dinner at the centre and were provided with packed evening and morning snack to eat at home. Food and beverages were weighed before and after meals and snacks.  
 
Across the 5-day menus they provided a variety of different vegetables and fruit, including:

The Winner

While both strategies increased fruit and vegetable consumption, the winner was:

Compared to the Control, Substitution increased vegetable intake by 41% (around 22 g) which was significantly different than the 24% increase (around 12 grams) found in the Addition group.
 
Impressed? Not really...

While the percent increase looks impressive, the absolute amounts are underwhelming.

The 12 g/d increase in the Addition strategy is equal to around one-fifth of a carrot.

Moreover, the children were provided with 300 g of vegetables in the Addition and Substitution treatments and only managed to eat just over one-quarter of this amount.

 
Fruit fared a little better

Children ate around half the portions supplied.

Intakes were similar between the two intervention groups with significant increases of 38% (around 69 g) for Substitution and 33% (around 60 g) for Addition compared to the Control.
 
So even though it’s encouraging that children do eat more when fed more, there’s a lot of food waste.
 
Previous work shows children prefer fruit to vegetables, and findings here are similar.

Not only did children eat a higher proportion of the fruit supplied, but they rated liking fruit more than vegetables.

What other components of the diet might change with Substitution? And are these changes for the better?

When we change one component of the diet, it’s important to assess the effects on overall food intake.

The Addition strategy increased daily food intake by 12% (69 g/d)  – attributable to greater fruit and vegetable intake with no evidence of a change in other foods.

However, the increase in food intake by 9% observed in the Substitution strategy was due to a due to a combination of greater fruit and vegetable intake and reduction in food from main dishes, and grain-based and dairy snacks.
 
And Substitution wins again

If calories are important, the Substitution strategy again comes out on top. There was a 6% (64 kcal/d) decrease in calories during Substitution, compared to a 5% (57 kcal/d) increase for Addition.

Regardless, energy density decreased in both Substitution (13%) and Addition (5%) compared to the Control.
 
Limitations? There are always a few...

This was only a 5-day trial. We don’t know whether the changes will be maintained.

Taking a closer look at the Addition strategy we see fruit intake steadily declined over the 5 days (although it remained above Control intakes).

Also, the generalisability of the results is limited. The children were from well-educated, high-income families – where most parents reported having as least an undergraduate degree.
 
With their fruit and vegetables provided, were children achieving recommended intakes?

Given the modest increases of fruit and vegetable intake in the trial, it was not surprising that most children were still consuming less vegetables than recommended.

Only three children met their vegetable recommendations – all during the Substitution strategy.

Fruit performed a little better. While only 25% met their recommendation during the Control condition, 57% and 45% met recommendations during the Substitution and Addition conditions, respectively.
 
So, what now?

The authors suggest a variety of strategies are needed.

In their previous work, hiding vegetables into recipes increased vegetable intake by around 67 g/d. This strategy doesn’t compromise palatability and there is less food waste.

However, they warn against using this strategy in isolation because repeated exposure to vegetables as snack or part of a meal can improve acceptability and thus intake. So, a combination of methods may be best.
 
Current food guides suggest half our plates should be fruit and vegetables.

Easier said than done, but substitution and hiding fruit and vegetables in meals may be two steps in the right direction.