Obesity

What is obesity?

Obesity means having too much body fat. In the UK, about 1 in 4 adults and 1 in 5 children aged 10-11 are living with obesity. It's become much more common in recent years.

How do you know if you have obesity?

The main way to check is using your Body Mass Index (BMI). This compares your weight to your height to see if you're in a healthy range.

You can use the NHS BMI calculator online. For most adults:

• Below 18.5 = underweight
• 18.5 to 24.9 = healthy weight
• 25 to 29.9 = overweight
• 30 to 39.9 = obese
• 40 or above = severely obese

Important: If you have Asian, Chinese, Middle Eastern, Black African or African-Caribbean family background, the numbers are different:

• 23 to 27.4 = overweight
• 27.5 or above = obese

BMI isn't perfect - very muscular people might have a high BMI without having too much fat. But for most people, it's a useful guide.

Another way to check: waist to height ratio

You can also measure around your waist at belly button level, then divide this number by your height (using the same units). If the answer is 0.5 or higher, you may have increased health risks.

For example: if your waist is 80cm and you're 160cm tall: 80 ÷ 160 = 0.5.

Why does obesity matter for your health?

Obesity can increase your risk of many serious health problems, including:

• Type 2 diabetes
• Heart disease
• Some cancers (like breast and bowel cancer)
• Stroke
• High blood pressure
• Sleep problems where breathing stops and starts during sleep
• Liver and kidney disease
• Pregnancy complications

It can also affect your daily life, causing:

• Feeling out of breath easily
• Sweating more
• Snoring
• Feeling very tired
• Joint and back pain
• Low confidence

What causes obesity?

It's usually caused by eating more calories than your body uses, especially from foods high in fat and sugar. But it's not just about willpower - many things can make it harder to maintain a healthy weight:

• Our environment makes it easy to eat unhealthy foods and hard to be active
• Your genes affect how your body stores fat
• Some medical conditions (like an underactive thyroid)
• Some medicines (including steroids and some blood pressure tablets)

What can help?

The best approach combines:

• Eating fewer calories with a balanced diet
• Being active for 150-300 minutes per week (like fast walking, swimming, or tennis)
• Getting support from weight management programmes

Speak to your GP if you're concerned about your weight. They can:

• Check if any medical conditions or medicines are affecting your weight
• Refer you to local weight management services
• Discuss medicines that might help if lifestyle changes aren't enough
• Talk about surgery options if appropriate

Remember: losing even a small amount of weight (3% of your body weight) and keeping it off can significantly reduce your health risks.

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Based on NHS.uk guidance. Written by Dr Krishnan Pasupathi, NHS GP.