The study, published by the National Institute of Nutrition last week, was conducted over 12 months on 5,028 students aged 7-17 from 75 schools in Hanoi, Ho Chi Minh City, the northern province of Thai Nguyen, the central province of Nghe An and the southern province of Soc Trang.

It found that overweight students tend to consume more protein-rich food. Many students, including those who are not overweight, tend to pursue unhealthy food habits, consuming sugary drinks and sweet food product.

Primary school students tend to consume more energy and protein foods than recommended, while secondary and high school students don’t consume enough food rich in energy, iron, zinc, calcium and other vitamins, the study found.

Low levels of physical activity and high screen time were contributing to the increased rate of obesity among urban kids.

The study also found that obesity rate among students decreased with age, while the rates of underweight students increased with age.

Tran Thuy Nga, who headed the study, said intervention programs were needed to combat malnutrition among rural children and obesity among urban ones.

Vietnamese people are consuming too much meat and not enough vegetables, experts said. The amount of meat consumed by an average Vietnamese has increased six times over the past 30 years, to nearly 100 grams a day. Their vegetable consumption yet has reduced to around 200 grams a day, half of the amount recommended by the World Health Organization.

Vietnam is also among the least physically active countries in the world, a Stanford University survey in 2017 found. It showed that an average person walked only 3,600 steps a day, compared to 4,000 steps in the Philippines, 5,800 steps in South Korea and 6,200 steps in China.

About 30 percent of the population do not get the physical recommended by the WHO, of at least 150 minutes a week, according to a study by the Ministry of Health.

Vietnamese children fared worse however. About 46 percent of students in secondary school and 39 percent in primary school in Hanoi and Ho Chi Minh City don’t get enough physical activity, the National Institute of Nutrition has estimated.

The lack of physical activity among Vietnamese children is partly attributed to the lack of priority given to physical education in schools and families, alongside increasing consumption of fast food and sugared beverages.

Authorities are trying to change the situation. The health ministry aims to reduce the number of people engaging in low activity from 30 percent to 10 percent by 2025. It has launched a campaign urging citizens to walk 10,000 steps a day to stay fit.

*Correction: An earlier version of this report said the rate of overweight children in urban Vietnam was 86 percent. But the National Institute of Nutrition, the author of the study, adjusted their figures later.