Canadian children and teens ate better during school hours in 2015 than in 2004, according to a study that dietitians say also showed major room to improve.

Researchers from the University of British Columbia's Food, Nutrition and Health program looked at what foods kids ate at school and during the school day in 2004 and 2015. The nationally representative data came from more than 7,000 students aged six to 17 or their parents who filled in detailed surveys about their diet for a day.

Then Claire Tugault-Lafleur, a postdoctoral research fellow, and her team scored the school-day (9 a.m. to 2 p.m.) diets on a 100-point scale for nutritional quality that considered 11 key components.

Kids' average nutrition scores during school improved 13 per cent from a decade earlier from 51.3 points to 58.0 points out of 100, the researchers said in Monday's issue of the journal Public Health Nutrition.

Why? The students crunched more fruits and veggies, slurped fewer sugar-sweetened beverages such as soda, fruit drinks and sports drinks, and chose considerably fewer calories from "minimally nutritious" foods like cookies and chips.

"It was definitely good news," said Tugault-Lafleur, the study's lead author.

School food programs across Canada vary considerably in quality, and a national, universal one could help, said Claire Tugault-Lafleur. (UBC Faculty of Land and Food Systems)

She also found school-day scores for dark green and orange vegetables, milk and alternatives and meat and alternatives improved, but stayed well below national recommendations at the time.

Previously, Tugault-Lafleur found a difference in diet quality between elementary and secondary school students.

"We wanted to look at whether the gap between older and younger children has improved or decreased over time," she said. "Basically everybody improved a little bit. Younger kids continued to eat more nutritiously than teens."

Dietitians say teens tend to eat more junk food when they leave school property while younger children eat what they've brought to school.

In 2015, children from food-insecure homes — where families lack access to food because they can't afford it — had lower diet quality scores compared with their peers from food-secure households. But that wasn't the case back in 2004, and it's a troubling sign.

The new Canada Food Guide focuses on filling half the plate with fruits and vegetables, a quarter with whole grains and a quarter with proteins to help bring down Canadians' intake of saturated fat and sodium, which increase the risk of heart disease. (CBC)

"It's definitely a cause for concern," Tugault-Lafleur said. That's where a universal, national, cost-shared healthy school food program comes in. Canada is the only G7 country without a national school food program.

"Currently we have some patchworks of programs but it's not comprehensive," she said. "There can be considerable variation in quality."

A national, universal school food program could help vulnerable Canadian students increase how much whole fruit, vegetables, whole grains, milk and alternatives they eat to move closer to national recommendations.

"It's something to think about in the next coming election," she said.

Kids can't learn when they're hungry

Dr. Catherine Pound, a pediatrician at the Children's Hospital of Eastern Ontario who wasn't involved in the research, said the findings underlined the need to focus on children from food-insecure households.

"When they're going to school hungry, they can't learn, they can't focus," said Pound, who also heads the Canadian Paediatric Society's nutrition and gastroenterology committee.

"It affects their development. We do see deficiencies in important nutrients. Depending on the severity, it certainly does have an impact on learning, brain development and health."

Toronto-based registered dietitian Leah Shainhouse works with people of all ages, coupling nutrition education with practical skills as simple as steaming green beans or choosing flavours that complement a meal while cutting back on sodium.

More nutrients, less sugar

Shainhouse said in the study, eating more fruit, vegetables and whole grains allowed students to have nutrients like vitamin A, B vitamins and fibre. In 2015, students also reduced their total sugar consumption, such as by choosing healthier snacks.

All provinces have introduced healthier changes in school, such as restricting sales of foods high in added sugar, fat and sodium.

To encourage more improvements, Shainhouse gives school and extracurricular workshops to teach nutrition and cooking skills to students, who often share the lessons with their parents.

"What I've noticed is especially with the younger kids when I've done some of these culinary classes they get super excited," Shainhouse said. "For instance if we do something where we're eating brown rice instead of white rice … they realize that they like it and they actually go home and influence what their parents are going to be purchasing."

Shainhouse hopes the new Canada Food Guide's focus on filling half the plate with fruits and vegetables, a quarter with whole grains and a quarter with proteins will help bring down Canadians' intake of saturated fat and sodium, which increase the risk of heart disease.