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Overweight and Obesity

Excess weight and obesity is becoming more common in Wales, and at the same time our collective ability to recognise what being a healthy weight looks like is reducing. This is a cause of significant public health concern, since carrying excess weight can have significant implications for an individual’s physical and mental health.

What is overweight and obesity?

At its simplest being overweight or obese is the result of an energy imbalance. It occurs when the amount of energy we take in as food is much greater than the energy we use going about our daily lives.
Therefore being overweight or obese describes someone who is carrying an excess of body fat, which results in weight gain. The most widely used measure of obesity is the body mass index (BMI) – weight in kilograms divided by height in metres squared. BMI provides a good indicator for levels of body fat.

  • BMI categories are:
  • underweight <18.5
  • healthy weight 18.5 to <25
  • overweight 25 to <30
  • obese 30 to <40
  • morbidly obese 40+

There are some other less common measures of obesity, including the waist to hip ratio, waist circumference and abdominal fat.

Why is obesity a problem in Wales?

Obesity prevalence is rising in Wales, as it is globally, and the healthcare costs associated with treating obesity are high and continuing to increase.

Being overweight or obese increases the risk of a wide range of chronic diseases, principally type 2 diabetes, hypertension, cardiovascular disease including stroke, as well as some types of cancer, kidney disease, obstructive sleep apnoea, gout, osteoarthritis, and liver disease, among others. Obesity is also associated with and contributes to a shortened lifespan. Our Health and its Determinants report gives an overview of the health and well-being of Wales.
It can also impair a person’s well-being, quality of life and ability to earn. Poor diet and a sedentary lifestyle are the main causes of overweight and obesity. Some people may also experience psychological problems such as low self-esteem, poor self-image, and low confidence levels.
Weight loss reduces all of these diseases in a dose-related manner: the more weight lost, and the closer to a healthy weight the individual becomes, the better the outcome. Obesity leads to an increased number of years of life lived with a disability and lowers life expectancy.

How many people does obesity affect in Wales?

The proportion of children and adults in Wales who are of a healthy weight is dropping:

  • Between 2003 to 2015 there was a 4% increase in levels of obesity among adults, and a 3.6% decrease in those of a healthy weight
  • Around 60% of adults (16 +) are overweight or obese – with a quarter of those classified as obese

Many of our sedentary behaviours start in childhood. For example, many primary and secondary school children are taken to school by car, which sets in place patterns of behaviour that then repeat throughout life.

The case for action on obesity in Wales establishes the scale of the challenge.

Obesity Infographic Causes

Obesity Infographic Impact

Obesity Infographic Scale

Overweight and Obesity Data and Information

Evidence: What works to tackle obesity?

Public Health Wales has produced a suite of evidence documents to support the Welsh Government’s ‘Healthy Weight: Healthy Wales’ strategy:

Evidence Reviews


International Perspectives International perspectives on action to prevent and reduce obesity

Literature reviews of international evidence, which includes a review of the literature gathered from around the world about innovative action on obesity.

Rapid review of ultra-processed food and obesity

This report examines the link between the consumption of ultra-processed foods and obesity.  It gives an overview of the literature, key studies and provides a working definition of ultra-processed food according to the NOVA classification.

Policy Context

The Public Health (Wales) Act 2017 required Welsh Government to produce an Obesity Prevention and Reduction strategy. Public Health Wales is supporting the Welsh Government in developing the first national obesity prevention and reduction strategy.

A consultation on the Welsh Government’s new plan to combat the greatest public health challenge facing Wales – obesity – has been launched by Health Minister Vaughan Gething.

You can submit your views during the consultation which ends on 12 April 2019.

Called ‘Healthy Weight: Healthy Wales’, it outlines the actions to be taken to help people in Wales maintain a healthy weight.

Wales has a very supportive policy context, including:

Public Health Wales Programmes

Every Child was launched in 2017 to improve the health and well-being of children. Part of its work includes 10 Steps to a Healthy Weight which outlines the key factors that increase the likelihood of a child being a healthy weight when they start school. The advice focuses on three age ranges: pre conception and pregnancy, 0-2 years and 2-5 years.

By 2030, we want Wales to have an environment and society in which healthy choices are the easy choices. This means increasing physical activity and promoting healthy weight. Find out more about how we're working towards a healthier future for Wales.

We are also utilising universal settings based approaches such as:

Contact details

For more information please contact:

Lucy O’Loughlin
Consultant in Public Health - Lead, Obesity and Nutrition programme