Teenagers turn 'food pyramid' upside down

Irish teenagers are in trouble if the old maxim "You are what you eat" is true

Irish teenagers are in trouble if the old maxim "You are what you eat" is true. A survey by students from Patrician College, Portlaoise, suggests that 13- to 16-year-olds have turned dietary advice literally on its head.

Elizabeth Parsons and Laura Byrne, both 14 and second-year students, described their work on the opening day of the Esat BT Young Scientist and Technology Exhibition 2003.

Judging got under way yesterday afternoon and continues through tomorrow afternoon after which the Young Scientist of the Year will be announced.

"It is all about the eating habits of teenagers from 13 to 16," explained Laura."We were trying to find out if we have a healthy diet."

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The answer was clear, added Elizabeth. "No we don't." The two surveyed 460 students from three schools in their area.

"We asked them to find out their food pyramid," Elizabeth said.

The familiar pyramid indicates the optimal diet for health with cereals and potatoes forming the wide base of the pyramid and the tasty but bad for you fatty foods, chocs and crisps, at the point.

When students filled in their personal eating habits, however, the pyramid was turned upside down, with biscuits and fatty foods forming the bulk of the diet and fruit and cereals the least often eaten foods. Both boys and girls indicated this eating pattern, they said.

Involvement in sports was also examined by the two. "About 84 per cent of boys participated in sports and 51 per cent of females," said Elizabeth.

Perversely, female involvement in sports was counterbalanced by an increased likelihood that they would eat more rubbish foods, added Laura.

While the sporty girls ate snack foods less often, they ate more at each sitting, she said. "Teenagers have an unbalanced diet and girls don't participate in sports because it is not available," she added.

They also asked a classmate to adjust her eating pyramid to the optimal to see whether eating habits could be altered.

"She said she felt better in herself," Laura said.

Food wasn't the issue for Brett Lawless (16), a transition year student from The High School, Rathgar, Dublin. His project involved teaching a computer how to teach itself, to learn from its experiences.

It was all about "neural networks", explained Brett, who entered the competition for the first time this year. He is in the process of putting together a new type of "learning algorithm" that enables a computer to interpret what it "sees" or "hears".

It starts appropriately enough with a "training programme", he said.

"You give the computer input and a desired output. The difference between the input and desired output is measured." The system can use this difference as a route to learning.

When it encounters something new it creates a new category for it, he explained.

More exposure to this same data allows it to sharpen its recognition of this category. Interpreting visual data requires it to look at a range of things such as motion, object edge detection and colour. If the object is unfamiliar, all of these feed into the definition of a new category of object which the computer then builds up for itself. It didn't matter if the data is visual or audible, he added.

He acknowledged that his project was a "work in progress" as he continued to add new elements to his teachable computer. He hoped to bring the project forward from this year's competition into the 2004 Young Scientist exhibition.

Dick Ahlstrom

Dick Ahlstrom

Dick Ahlstrom, a contributor to The Irish Times, is the newspaper's former Science Editor.