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Obesity is more than just a few extra pounds.


Obesity is the heavy accumulation of fat in your body to such a degree that it rapidly increases your risk of diseases that can damage your health and knock years off your life, such as heart disease and diabetes.


The fat may be equally distributed around the body or concentrated on the stomach or midrift (apple-shaped) or the hips and thighs (pear-shaped).


For medical purposes, the body mass index (BMI) is used to determine if your weight is in the healthy range.


Doctors use BMI because it compares your weight against your height.


However, it's now recognized that central obesity (apple shaped obesity) is especially harmful to health. So, it's also recommended that abdominal waist measurements are done to assess overweight.



BMI – test yourself


The significance of your BMI will depend on whether you are apple or pear shaped.


Use a tape measure to measure your waist (usually at belly button level) and your hips (the widest part of your pelvis).


For a woman, an ideal waist measurement is less than 80cm (32 inches), 80cm to 88cm (32 inches to 35 inches) is high and more than 88cm (35 inches) is very high.


For a man, ideal is less than 94cm (37 inches), high is 94cm to 102cm (37 inches to 40 inches) and very high is more than 102cm (40 inches).


To work out your waist-to-hip ratio, divide your waist measurement by your hip measurement.


A ratio of 1.0 or more in men or 0.85 or more in women indicates that you have too much fat around your middle, putting you at increased risk of diseases that are linked to obesity, such as type 2 diabetes and heart disease.


  • You are in the normal range if your BMI is between 18.5 and 25 (kg/m2).


  • You are overweight if your BMI is between 25 and 30.


  • You are obese if your BMI is 30 or higher.


  • You are morbidly obese if your BMI is 40 or higher.


    How common is obesity?


UK statistics in 2009 showed that 44 per cent of men and 33 per cent of women were classified as overweight in 2009 (BMI 25 to less than 30kg/m2) and almost a quarter of adults (22 per cent of men and 24 per cent of women were obese (BMI 30kg/m2 or over).


This is more than 12 million people, placing huge demands on the health service for diseases related to obesity – such as diabetes and obesity, especially central or apple-shaped obesity are rapidly increasing, especially in young people.


At least one in three children between the ages of 2 and 15 are overweight.

Government statistics also show that children are more likely to have a weight problem if one parent is overweight, and this risk is increased if both parents are overweight or obese.


  • 14 per cent of boys are overweight.

  • 17 per cent of girls are overweight.

  • 19 per cent of boys are obese.

  • 18 per cent of girls are obese.


Government statistics also show that children are more likely to have a weight problem if one parent is overweight, and this risk is increased if both parents are overweight or obese.


What problems can obesity cause?


Psychologically, being overweight can affect your body image and damage self-esteem. In some cases this can cause social anxiety and depression.


Common physical problems include:


  • difficulties breathing

  • difficulties walking or running

  • increased sweating

  • pain in the knees and back

  • skin conditions such as acne

  • gallstones.


The following medical conditions are also more common in obese people than in those of normal weight:



These conditions are often known as obesity-related diseases and are some of the most common causes of death before the age of 75. This is why obesity increases your risk of mortality.



What causes obesity?


Obesity can be hereditary, so some people are at increased risk.


Genetic factors can affect appetite, the rate at which you burn energy (metabolic rate) and how the body stores fat.


These genetic factors simply put you at increased risk of becoming overweight because they alter your eating or energy burning habits.


But some diseases which have a genetic component can also lead to obesity, including polycystic ovary syndrome (PCOS) and hypothyroidism.


But even if your genes make weight gain more likely, it is not inevitable that you will be overweight.


Obesity develops from:


  • overeating

  • irregular meals

  • lack of daily physical activity.


This is why obesity has trebled since 1980, when only 6 per cent of men and 8 per cent of women were obese.


In this time our lifestyles have changed rapidly, with the ready availability of energy-dense (fatty and sugary) convenience foods and car journeys replacing walks to work and school.


Lifestyle is one of the most important factors that determine how far the genetic predisposition to weight gain develops – the good news here is that we can make choices about our lifestyle to control this weight gain.


Medicines such as antidepressantscorticosteroids and oral contraceptives can also cause weight gain.



                       When is obesity dangerous?


If you have a BMI of more than 25, you should lose weight.


The same is true if you carry too much fat around the middle because this increases your risk of heart disease and diabetes.


Your waist should be no more than 102cm/40 inches (men) or 88cm/35 inches (women), with stricter targets for Asians of less than 90cm/35 inches (men) and 80cm/32 inches (women) (because people of Asian origins develop obesity related disease, such as diabetes at much lower levels of overweight).



                             How is obesity treated?


Initially, your doctor will suggest you lose weight through a change in diet and an increase in physical exercise.


Clinical guidelines are to aim for a weight loss of between 5kg and 10kg (11 to 22lb) over three months. This equals about 0.5kg or 1lb per week.

If you are obese, losing this amount will have a positive effect on your risk of cardiovascular disease and diabetes by reducing blood pressure, blood sugar (glucose) and cholesterol levels.


A dietitian can help you lose weight by giving nutritional advice on buying and preparing foods and designing a weight-loss plan.


Weight-loss plans are usually based on a low-fat diet of between 1500 and 2000 calories a day, which will result in a weight loss of 5 to 10kg in more than 90 per cent of obese people.


                               How do diet and exercise help?


Your body needs a certain amount of energy (calories) each day. Excess energy is stored as fat. The more active you are, the more calories your body needs.


By eating less than your body needs and exercising more, you force your body to use its existing fat stores for energy.


By burning excess fat, you lose weight. Abdominal or central obesity (apple shapes) is particularly responsive to exercise.


Every human body needs exercise to stay healthy.


Ideally we should all aim for at least 150 minutes of moderately intense exercise each week (ideally 30+ minutes at least 5 days a week).


This is exercise intense enough to leave you feeling out of breath and raise your pulse rate up to 65 to 80 per cent of maximum.


If you combine this amount of exercise with a healthy diet, you should steadily lose weight down to a healthy level.


Based on a text by Professor Arne Astrup


What is obesity?

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