Overweight and obesity are defined as abnormal or excessive fat accumulation that presents a risk to health. In adults, they are commonly classified by the body mass index (BMI) – a person's weight in kilograms divided by the square of their height in metres (kg/m2). A person with a BMI equal to or more than 25 is considered overweight, while a BMI of 30 or more is generally considered obese.
- Obesity is a global, preventable health crisis.
- There are more than one billion obese people in the world.
- WHO estimates that by 2025, approximately 167 million adults and children will become less healthy because they are overweight or obese.
- Obesity and overweight can lead to physical and mental health problems.
- Simple practical measures can help to manage weight.
Why is managing weight important?
- Obesity is a disease that affects most body systems – the heart, liver, kidneys, joints, and reproductive system.
- Obesity and being overweight leads to a range of noncommunicable diseases, such as type 2 diabetes, cardiovascular disease, hypertension and stroke.
- Osteoarthritis and other musculoskeletal disorders are more common among overweight people.
- Many cancers are linked to obesity.
- Obesity and overweight can lead to gastroesophageal reflux, urinary stress incontinence and infertility.
- Obesity can also affect quality of life and lead to depression, anxiety and low self-esteem.
- Sleep disturbance such as apnoea and breathing problems are commonly linked to obesity.
Reasons for obesity and overweight
- Obesity and overweight develop gradually over time, as a result of poor diet and lifestyle choices.
- The fundamental cause is an energy imbalance between calories consumed and calories expended – which usually results from an increased intake of energy-dense foods that are high in fat and sugars, and an increase in physical inactivity.
- To maintain a healthy weight, an average physically active man needs about 2,500 calories and a woman 2,000 calories a day.
- Weight gain may also result from a rare genetic condition, an underlying medical condition, or certain medicines (such as some corticosteroids, or medications for epilepsy, diabetes and mental illness).
Practical tips for managing weight
- To lose weight at a safe and sustainable rate of 0.5 to 1kg a week, most people are advised to reduce their energy intake by 600 calories a day.
- Swap unhealthy and high-energy foods – such as fast food, processed food and sugary drinks (including alcohol) – for healthier choices.
- Eat at least five portions of a variety of fruit and vegetables every day. They can be fresh, frozen, canned, dried or juiced.
- Starchy carbohydrates (such as potatoes, bread, rice, pasta and cereals) should make up just over a third of the food you eat. Choose higher fibre or wholegrain varieties, such as wholewheat pasta, brown rice, or potatoes with their skins on.
- Cut down on saturated fat. This is found in many foods, such as fatty cuts of meat, sausages, butter, cheese, and processed food. When you are having meat, choose lean cuts and cut off any visible fat. Choose foods with unsaturated fats, such as oily fish, and vegetable oils and spreads.
- Avoid trying to lose weight quickly by crash dieting, as it carries many risks, including vitamin deficiency and creating new health problems.
- Take regular exercise to greatly increase your chance of long-term weight loss.
- A behaviour modification programme can help you make lifestyle changes, lose weight, and maintain a healthy weight. It helps you identify what has contributed to your obesity and set realistic weight loss goals.
- Always consult a doctor or nutritionist before taking over-the-counter and prescription weight loss drugs.
You can also get in touch with the ITF using the ITF Wellbeing app or ITF Wellbeing Facebook page for guidance on overweight and obesity.