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Danish research: Vegetables hidden in a snack do not make children like the vegetables more

Article A research experiment with 256 Danish schoolchildren concludes that when the children repeatedly eat snack bars enriched with beetroot, carrot or pumpkin, the children might increase their liking of the snack bar but not of the vegetables themselves. 

If you want your children to eat more vegetables, adding vegetables to snack bars is not necessarily advantageous. 

This is the conclusion of a Danish research experiment conducted by a team of scientists from the University of Copenhagen with Taste for Life affiliate Annemarie Olsen in charge. The results have been published in the scientific journal Appetite. 

“We know that if children are exposed to a new taste experience repeatedly over time they will, in general, end up liking it. However, this is not the case with vegetables. Consequently, it could be an option to add vegetables to a popular snack such as a fruit bar and hope that the children eventually would come to like the vegetables they know from the snack. But our research shows that this is not the case. In our experiment, the children learned to appreciate the taste of the snack bar, but not the taste of the vegetables inside it”, Annemarie Olsen explains.

If you want to help your children to become better at accepting vegetables, Annemarie Olsen recommends that you “play with open cards” and present the vegetables to the children so they can get to know them. 

256 children tasted and judged snack bars with vegetables

256 Danish children between the age of 7 and 10 participated in the experiment. The purpose of the study was to examine if the children’s accept and appreciation of vegetables are affected when the vegetables are hidden in a snack – in this case a fruit bar enriched with different vegetables.

Each child received a fruit bar eight times through a period of time. The children were divided in groups exposed to either a vegetable-enriched fruit bar or a fruit bar without any vegetables. The groups received specially produced fruit bars made by the typical date paste mixed with:

  • Beetroot/carrot
  • Spinach/Jerusalem artichoke
  • Pumpkin/sweet potato
  • Neutral – which means a date-based fruit bar without any vegetables

A fifth group of children were exposed to the beetroot/carrot fruit bars every day while the other groups were exposed to the fruit bars every second day. This fifth group could inform whether the children would become bored with the food when they had the same snack for eight days in a row. 

A sixth group of children served as a control group and were not exposed to any fruit bars.

"Stealth"-vegetables: When the pointed cabbage is hidden in the lasagne 

But why hide vegetables in a popular snack?

In general, children prefer the food they know and like. In the supermarkets’ snack or bread section, for instance, you will find several examples of foodstuffs known by children which are enriched with vegetables. 

”In science, this is called ”vegetables by stealth”. The method is known by many parents, food manufacturers and food professionals as the trick of adding finely chopped or pureed vegetables to e.g. Bolognese sauce, lasagne, soup or bread and buns. The taste of the vegetables is not meant to be notable. According to the parents, the strategy is meant to make the children eat vegetables which they would otherwise have rejected,” Annemarie Olsen explains. 

However, it is much debated whether the children will learn to know and appreciate the vegetables being hidden in the food. For instance, will the child come to like pointed cabbage by eating lasagne in which the vegetable is hidden?

This effect, called the generalisation effect, occurs most often when the well-known and unknown food is similar in both taste and texture. If the two types of food are too different, it is not certain that the good taste of e.g. the well-known lasagne will make the unknown celery taste good.

What do vegetables known from a fruit bar taste like?

The 256 children in the experiment would help clarify if a generalisation effect from fruit bars to vegetables exists. 

In the beginning and in the end of the experiment the researchers measured how much the children liked the fruit bars and the individual vegetables which had been added to the bars. The children tasted small, raw pieces of the vegetables and judged how well they tasted. 

The results showed that the children did not change their opinion on the vegetables’ taste during the experiment. In other words, there was no generalisation effect based on the vegetable-enriched fruit bars.

“This means that children will not necessarily begin to accept or like more vegetables just because they have been added to a fruit bar,” Annemarie Olsen explains.

Besides, the results showed that the children’s’ liking of the fruit bars enriched with vegetables increased during the experiment. However, the effect was only significant for the fruit bars with beetroot/carrot and pumpkin/sweet potato. The children’s favourite was the neutral fruit bar – the one without any vegetables. 

Additionally, the experiment showed that the children who were exposed to a fruit bar every day eventually began to like it less. 

A strategy still interesting for some 

”This study shows that it apparently not is an effective strategy to add vegetables in other food products in order to make children like vegetables more. Often, it will be more appropriate to present the vegetables to the children as they are. However, to be able to draw more conclusions, we need more research,” Annemarie Olsen says. 

And she will not completely advise against the camouflaged vegetables:

“In return, the adding of vegetables in the food can make children, who would otherwise reject vegetables, eat more vegetables. Even if the children do not get to know the taste of the vegetables in this way, they will still benefit from the vitamins and minerals in the vegetables. Thus, for some children this approach could still be interesting,” Annemarie Olsen says. 

Mentioned in the article

Associate Professor, PhD

Associate Professor, PhD, University of Copenhagen

Annemarie Olsen is a member of Taste for Life’s management and part of the focus area Science of Cooking. Her research relates to human eating behavior in the area of sensory and consumer research, primarily focusing on children. Main topics are food preferences and intervention strategies.

She is also Head of Studies for the MSc programme in Food Innovation and Health at the University of Copenhagen.