Food and Nutrition Notes

Obesity and Overweight

Obesity is one of the most serious health problems in the world, no longer just affecting the affluent countries. The World Health Organisation (WHO) defines ‘overweight’ and ‘obesity’ as ‘abnormal or excessive fat accumulation that may impair health.’


Obesity is a health issue resulting from a combination of causes and factors.

Body Mass Index

‘Body mass index (BMI) is a simple index of weight-for-height that is commonly used to classify overweight and obesity in adults. It is defined as a person’s weight in kilograms divided by the square of his height in meters (kg/m2).’’

Body mass index is a commonly used medical term to determine overweight and obesity in adults. The World Health Organisation defines ‘overweight’ as having a BMI equal to or more than 25 and ‘obese’ as having a BMI equal to or more than 30.

This method of classifying body weight applies to adult men and women, except during pregnancy and old age. Children have their own BMI range, which takes age, gender, height and weight into account.

Fat Distribution

Fat distribution is a useful guide to determine whether or not someone is overweight or obese. Generally, individuals with fat distribution around the hips, thighs and bottom are classified as ‘pear shaped’, whilst individuals with fat distribution around the stomach and chest are classified as ‘apple shaped.’

Those who are ‘apple shaped’ are more at risk to obesity-related diseases such as cardiovascular disease (CVD) due to an accumulation of fat around the heart. There are many other health risks associated with being overweight or obese, and childhood obesity is severely affecting the health of children. They are likely to carry this body shape (and also any health issues associated with it) through to adulthood.

Common Health Consequences

Being overweight or obese (having a raised BMI) is a major risk factor for noncommunicable diseases and health risks such as:


According to WHO:

Dietary Advice to Manage Obesity

To help maintain a healthy weight, the Eatwell Guide recommends that adult men should not exceed 2500kcal per day, and adult women should not exceed 2000kcal per day from all foods and drinks.

Individuals should also follow the Eatwell Guide to make healthy choices that could have a positive impact on energy balance, such as:

Lifestyle Advice to Manage Obesity

Physical activity and sleep are both lifestyle factors that may contribute to the development of obesity.

Adults should try to sleep for 7.5 to 9 hours per night, and children should sleep for 8 to 11 hours per night.

As well as helping to control body weight overall, exercise also helps to control appetite. Adults should also aim for approximately 150 minutes of exercise per week, whereas children should exercise (moderate intensity) for 60 minutes per day.