Primary 1 Body Mass Index (BMI) statistics Scotland
School year 2024 to 2025

About this release

This annual release from Public Health Scotland (PHS) provides statistics on healthy weight, using body mass index (BMI) for Primary 1 school children (those aged around 5 years old), and includes data for school years 2001/02 to 2024/25. Statistics in this release are derived from height and weight measurements collected at health reviews in Primary 1.

Main points

• In school year 2024/25, 74% of Primary 1 children measured had a healthy weight, 24% were at risk of overweight or obesity and 1% were at risk of underweight.
• The percentage of both boys and girls at risk of obesity (both 12%) has increased compared with the previous year (11% and 10% respectively). The greater increase among girls means that the previous gap between boys and girls has closed.

Figure 1 is a line chart showing the trend in primary 1 children at risk of obesity by sex for school years 2001/02 to 2024/25 main points given in summary.

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Figure 1: Percentage of Primary 1 Children at risk of obesity by sex, school years 2001/02 to 2024/25, Scotland

• The percentage of children at risk of overweight or obesity has risen to 24% in 2024/25 from 22% in 2023/24.
• Data on differences in healthy weight between groups is monitored to assess how children's circumstances, such as access to affordable healthy food, is influencing inequalities in growth and nutrition. In 2024/25 children living in the most deprived areas (as measured by SIMD) were twice as likely to be at risk of obesity (16%) than children living in the least deprived areas (8%). There are also differences in healthy weight by ethnicity.
• In school year 2024/25 a total of 47,312 children had valid height and weight measurements recorded in Primary 1. This is approximately 87% of children aged 5 in Scotland, a small decrease from the previous year.

Background

Monitoring healthy weight across the child population is a way of seeing how well the needs of children are being met. Maintaining a healthy weight through childhood is associated with many health benefits. A child’s BMI is calculated by dividing their weight (in kilograms) by their height (in metres) squared. Children are then allocated to a healthy or unhealthy weight category by comparing their BMI to the range of BMIs seen among a reference group of children of the same age and sex. This summary provides information on the proportion of children found to be at risk of having an unhealthy weight based on the thresholds used for monitoring the health of the child population.

Further information

The next release of this publication will be December 2026.