Overweight and obesity (BMI)

• Crude = results weighted for season, age, sex, and socioeconomic status.
• Older adults (65 years and above) do not include institutionalised (including those in care homes) or hospitalised individuals, or those who could not be interviewed without assistance (e.g., individuals with dementia).

• Among the Belgian adult population the average BMI is 26.6 kg/m².
• The average BMI increases with age.
• The average BMI is higher in men than women, particularly among individuals aged 65 years and above.

• Among the entire population of Belgium aged three and above, 47% have a normal weight, 31% have overweight, 18% have obesity, and 4% have underweight.
• Among children and adolescents, the proportion of those with a normal weight is 72% and 69% respectively. However, as individuals age into adulthood, the proportion of those with a normal weight declines, with a corresponding rise of overweight and obesity.
• Differences by sex are apparent in middle-aged and older adults, where men are more likely to have overweight (including obesity) than women.

• Crude = results weighted for season, age, sex, and socioeconomic status.
• For adults, underweight is defined as having a BMI lower than 18.5 kg/m², while normal weight falls between 18.5 kg/m², and 24.9 kg/m². Overweight is categorised as having a BMI between 25.0 kg/m², and 29.9 kg/m² and obesity is defined as a BMI greater than or equal to 30 kg/m² according to the World Health Organization (WHO).
• In children and adolescents, this classification is age and sex-specific, as defined by Cole & Lobstein (2012).
• Older adults (65 years and above) do not include institutionalised (including those in care homes) or hospitalised individuals, or those who could not be interviewed without assistance (e.g., individuals with dementia).

• Crude = results weighted for season, age, sex and socioeconomic status.
• In adults, overweight (including obesity) is defined by the World Health Organization (WHO) as having a BMI above or equal to 25.0 kg/m².
• In children and adolescents, this classification is age and sex-specific, as defined by Cole & Lobstein (2012).
• Older adults (65 years and above) do not include institutionalised (including those in care homes) or hospitalised individuals, or those who could not be interviewed without assistance (e.g., individuals with dementia).

• Among the entire population in Belgium aged 3 and above, 49% have overweight (including obesity).
• The proportion of individuals with overweight (including obesity) increases with age. While the proportion remains relatively constant in children and adolescents, it increases significantly from adulthood. Among older adults, 64% of women and 80% of men are classified as having overweight (including obesity).
• Overall, men are more likely to have overweight (including obesity) (53%) than women (46%). This difference is only visible among middle-aged and older adults. In young people there are no significant differences in overweight (including obesity) by sex.

• Crude = results weighted for season, age, sex and socioeconomic status.
• In adults, overweight obesity is defined by the World Health Organization (WHO) as having a BMI above or equal to 30.0 kg/m².
• In children and adolescents, this classification is age and sex-specific, as defined by Cole & Lobstein (2012).
• Older adults (65 years and above) do not include institutionalised (including those in care homes) or hospitalised individuals, or those who could not be interviewed without assistance (e.g., individuals with dementia).

• 18% of the Belgian population aged 3 years and above have obesity.  
• The proportion of individuals with obesity increases with age. It is the lowest in children (4%) and adolescents (7%) and the highest in older adults (28%).
• The proportion of individuals with obesity is the same for men and women, except among older adults, where more men (32%) have obesity than women (24%).

• Crude = results weighted for season, age, sex and socioeconomic status.
• For adults, underweight is defined as having a BMI lower than 18.5 kg/m², while normal weight falls between 18.5 kg/m², and 24.9 kg/m². Overweight is categorised as having a BMI between 25.0 kg/m², and 29.9 kg/m², and obesity is defined as a BMI greater than or equal to 30kg/m², according to the World Health Organization (WHO).
• In children and adolescents, this classification is age and sex-specific as defined by Cole & Lobstein (2012).
• The educational level is calculated at the household level by considering the highest diploma obtained by: (i) the respondents or their partner for adults (aged 18 years and above), or (ii) the father and mother (or carer, if applicable) for children and adolescents (aged 3 to 17 years). However, for simplicity, we refer to the education level of individuals rather than the education level of their households.

• In the Belgian population aged three and above, 40% of the low-educated have a healthy weight, compared to 47% among the mid-educated and 59% among the highly educated.
• The proportion of individuals with overweight or obesity declines with the level of education.
• Among the highly educated, 27% have overweight, compared to 33% among the low- educated.
• Among the highly educated, 10% have obesity, compared to 23% among the low- educated.

• Adjusted = results weighted for season, age, sex and socioeconomic status, and adjusted according to age and sex based on linear regression model (using the Belgian population of 2022-2023 as reference).
• In adults, overweight (including obesity) is defined by the World Health Organization (WHO) as having a BMI above or equal to 25.0 kg/m².
• In children and adolescents, this classification is age and sex-specific as defined by Cole & Lobstein (2012).

• Overall, the proportion of individuals with overweight (including obesity) remained constant in the Belgian population aged 18 to 64 years old, except in Wallonia where the proportion decreased from 50% to 45% between 2014-2015 and 2022-2023.

• Adjusted = results weighted for season, age, sex and socioeconomic status, and adjusted according to age and sex based on linear regression model (using the Belgian population of 2022-2023 as reference).
• In adults, obesity is defined by the World Health Organization (WHO) as having a BMI above or equal to 30.0 kg/m².
• In children and adolescents, this classification is age and sex-specific as defined by Cole & Lobstein (2012). 

• Overall, the proportion of obesity remained constant in the Belgian population aged 18 to 64 years old, except in Brussels where the proportion increased from 12% to 18% between 2014-2015 and 2022-2023.
• The proportion of individuals with obesity is higher in Wallonia (20%) than in Flanders (14%).

• Adjusted = results weighted for season, age, sex and socioeconomic status, and adjusted according to age and sex based on linear regression model (using the Belgian population of 2022-2023 as reference).
• In adults, overweight (including obesity) is defined by the World Health Organization (WHO) as having a BMI above or equal to 25.0 kg/m².
• In children and adolescents, this classification is age and sex-specific as defined by Cole & Lobstein (2012). 

• The proportion of individuals with overweight (including obesity) in the Belgian population aged 3 to 64 years old has remained unchanged between 2014-2015 and 2022-2023, across all groups.

• Adjusted = results weighted for season, age, sex, and socioeconomic status, and adjusted according to age and sex based on linear regression model (using the Belgian population of 2022-2023 as reference).
• In adults, obesity is defined by the World Health Organization (WHO) as having a BMI above or equal to 30.0 kg/m².
• In children and adolescents, this classification is age and sex-specific as defined by Cole & Lobstein (2012).

• The proportion of individuals with obesity in the Belgian population aged 3 to 64 years old has remained unchanged between 2014-2015 and 2022-2023, across all age groups.