What Are the Health Risks of Obesity?

Obesity can affect many aspects of health, increasing the risk of conditions such as heart disease, type 2 diabetes, and high blood pressure.

These risks develop gradually over time, as excess body fat places pressure on organs.

Understanding the health risks and consequences of obesity can help people take action and manage their weight to protect their long-term well-being. Learn everything you need to know in the guide below.

At a Glance

• Obesity is a medical condition defined by a BMI of 30 or higher, and it can increase the risk of several long-term health problems.
• Living with obesity may raise the likelihood of conditions such as heart disease, type 2 diabetes, high blood pressure, sleep apnoea, certain types of cancer, joint problems, kidney diseases, and more.
• The condition usually develops due to multiple factors, including excess calorie intake, low physical activity, genetics, poor sleep and stress.
• Preventing and managing obesity often involves lifestyle changes, such as following a balanced diet, staying physically active and seeking professional support when needed.

What Is Obesity?

According to the WHO, obesity is a medical condition where a person carries excess body fat that may negatively affect their health. It is generally diagnosed in adults with a Body Mass Index (BMI) of 30 or higher.

While BMI does not measure body fat directly, it is widely used in healthcare to identify people who may be at greater risk of weight-related health conditions.

Obesity develops over time when energy intake (calories) consistently exceeds energy used by the body.

How Do You Know If You're Living With Obesity?

You’re living with obesity if you have a BMI over 30.

BMI is calculated using your weight and height. In adults, the categories are generally:

1. BMI below 18.5 → Underweight
2. BMI 18.5 - 24.9 → Healthy weight
3. BMI 25 - 29.9 → Overweight
4. BMI 30 - 34.9 → Obesity (Class 1)
5. BMI 35 - 39.9 → Obesity (Class 2)
6. BMI 40 or above → Severe obesity (Class 3)

How to calculate your BMI

1. Multiply your height (metres) by itself.
2. Divide your weight (kg) by the result.

Example:

• Weight: 90 kg
• Height: 1.80 m

Calculation:

90 ÷ (1.80 x 1.80) = 27.77 BMI (overweight)

For common health questions about BMI, watch the following video:

Health Risks of Obesity

Living with obesity can increase the risk of several medical conditions. Below are some of the most well-established health risks associated with obesity:

1. Heart Disease

Obesity is strongly linked to cardiovascular disease.

Excess weight and body fat can make your heart work harder to send blood to your body. They can also contribute to:

• Increased cholesterol levels
• Inflammation

Over time, this can increase the likelihood of heart attacks, heart failure, angina, and more.

Read more: Heart Disease: Risks, Symptoms & Treatments.

2. High Blood Pressure (Hypertension)

Carrying excess weight can lead to blood flowing through your vessels with a force greater than usual (that’s hypertension).

This way, your heart has to pump harder to send blood to your cells.

Read more: Blood Pressure Readings: What Do Your Numbers Mean?

3. Type 2 Diabetes

Type 2 diabetes is a condition where your body can’t use or produce enough insulin, leading to high blood sugar (glucose) levels. 

Having a large body size can reduce your body’s sensitivity to insulin, making it harder to regulate blood sugar levels.

Discover practical tips for managing diabetes in our useful guide!

4. Joint Problems & Osteoarthritis

Living with obesity places increased pressure on your joints and cartilage, leading to pain, swelling, limited range of motion, and osteoarthritis. 

The joints mostly affected include:

• Knees
• Hips
• Lower back
• Ankles

Browse all our quality arthritis medications:

5. Sleep Apnoea

Living with overweight or obesity means more fat concentrated around your neck, which obstructs normal breathing patterns during sleep (makes the upper airway smaller) and often leads to obstructive sleep apnoea.

If sleep apnoea is left untreated, it may lead to various health conditions, such as heart disease, diabetes, high blood pressure, and more.

6. Certain Types of Cancer

Research has shown that obesity is linked to several types of cancer, including:

• Breast cancer
• Bowel cancer
• Kidney cancer
• Ovarian cancer
• Thyroid cancer
• Colorectal cancer
• Esophageal cancer
• Multiple myeloma
• Meningioma

Overweight and obesity can cause chronic inflammation, increased hormone levels, and metabolic changes — all of which promote rapid cell division and may lead to cancer.

7. Fatty Liver Disease

Obesity can lead to the buildup of fat in the liver, which can cause liver damage, such as scarring, liver failure, and liver cancer.

8. Kidney Disease

Excess body weight may place additional strain on the kidneys, which are responsible for filtering waste and excess fluids from the blood.

Obesity can also increase the risk of diabetes and high blood pressure, which are the main causes of chronic kidney disease (CKD).

9. Pregnancy Complications

Obesity can also raise the likelihood of pregnancy-related problems, posing a threat to both the mother and the baby.

Possible pregnancy-related risks for the mother include:

• Gestational diabetes
• Preeclampsia (high blood pressure during pregnancy)
• Labour and delivery complications, such as the need for a C-section or prolonged labor
• Weight retention after giving birth

Possible pregnancy-related risks for the baby include:

• Congenital anomalies, such as neural tube defects, heart defects, etc.
• Stillbirth
• Macrosomia (being born larger than expected)

What Are the Most Common Health Risks of Obesity in Adults?

Some conditions occur more frequently in adults living with obesity. These include:

• Heart disease
• Type 2 diabetes
• High blood pressure
• Stroke
• Osteoarthritis
• Sleep apnoea
• Fatty liver disease
• Certain cancers
• Chronic kidney disease

What Are the Most Common Health Risks of Obesity in Children?

Childhood obesity can also lead to serious health issues. Some common risks include:

• early signs of type 2 diabetes
• high blood pressure
• breathing difficulties
• joint problems
• Idiopathic intracranial hypertension
• low self-esteem and mental health challenges

Other Obesity-Related Problems

Apart from medical conditions, obesity can also lead to:

• Breathlessness
• Snoring
• Increased sweating
• Tiredness
• Difficulty sleeping
• Feeling isolated
• Low-self esteem, anxiety, depression

Main Causes of Obesity

Common contributing factors include:

• consuming more calories than the body uses
• limited physical activity
• highly processed foods and sugary drinks
• genetics and family history
• hormonal changes
• poor sleep patterns
• stress and emotional eating
• environmental and lifestyle factors

Prevention & Treatment of Obesity

Prevention Strategies

• Follow a healthy, balanced diet, rich in whole foods, fruits, vegetables, lean protein, and more (see what foods help with weight loss).
• Stay physically active.
• Get enough sleep.
• Manage your stress levels.

Treatment Options

In addition to the prevention strategies we saw above, you can also:

• Consider reliable diet supplements, but only as part of a broader weight management plan and after consulting your GP or pharmacist.
• Join a structured weight management programme, such as Weldricks’ weight loss service.
• Have weight loss (bariatric) surgery (for severe obesity only).

Read also: How Do Weight Loss Medications Work? 

Health Risks of Obesity — Final Thoughts

Obesity is a complex condition affecting many areas of health, from heart problems and diabetes to joint problems, sleep or breathing difficulties.

Fully understanding the health risks associated with this condition is an important step towards prevention and long-term well-being.

If you have any questions about obesity or weight-related concerns, the Weldricks pharmacy team is here to help. Contact us now, and a trained professional will be happy to provide clear, reliable guidance and support.