29.AUG.2017 10 MIN READ | 10 MIN READ

We have been told one too many times that being overweight or obese is bad, but did you know the extent of damage obesity has on your health?

Last updated on 19 October 2020

Obesity significantly increases your risk of diabetes and high blood pressure, and these conditions are also intimately intertwined with heart disease. For instance, an obese person’s risk of a heart attack is 3 times greater than that of a person who has a healthy weight.

Obesity vs overweight

Although we have been using these 2 words interchangeably, there is a subtle difference in their medical definitions.

Obesity is a condition where a person has accumulated so much body fat that it might have a negative impact on their health. This is different from being overweight, where the weight may come from muscle, bone, fat or body water.

If you weigh at least 20% more than your ideal weight, you are considered obese. To calculate your ideal weight, health professionals have suggested using your body mass index (BMI) as a rough indicator. If your BMI is 30 or above, you are considered obese.

Do keep in mind that this is a very rough gauge and having a higher than normal BMI does not necessarily mean you are unhealthy. Imagine bodybuilders! They are constantly building muscle, which means they are also putting on weight but it does not mean that their health is at stake.

Obesity can happen for many different reasons, such as consuming too many calories, leading a sedentary lifestyle and getting insufficient sleep. But regardless of the reason, being obese puts one in danger of certain illnesses, such as type 2 diabetes, high blood pressure and heart disease.

How obesity increases your risk for type 2 diabetes

People who are obese have a high risk of developing type 2 diabetes, which is also known as insulin-resistant or adult-onset diabetes. This is a condition where your blood glucose level is persistently high.

Research suggests that people who are obese are up to 80 times more likely to develop type 2 diabetes than those who are not.

In obese persons, cells of fat tissues have to process more nutrients than they can manage. The stress in these cells triggers an inflammation that releases a protein known as cytokines. Cytokines then block the signals of insulin receptors, thus gradually causing the cells to become resistant to insulin.

Insulin allows your cells to use glucose (sugar) for energy. When you are resistant to insulin, your body is unable to convert the glucose into energy and you end up with a persistently high blood glucose level.

Besides suppressing normal responses to insulin, the stress also triggers inflammation in cells that can lead to heart disease.

The link between diabetes and heart disease

Compared to people without diabetes, people who have diabetes are at higher risk for severe heart disease, such as coronary heart disease heart failure or diabetic cardiomyopathy (heart muscle disorder).

This is because over time, high blood glucose from diabetes damages blood vessels and the nerves that control the heart and blood vessels. Additionally, people with diabetes also have other conditions such as high blood pressure and obesity that further raise their risk of developing heart disease.

However, there are steps that can be taken to reduce the risk of developing heart disease if you have diabetes. These include:

  • Keeping your blood glucose, blood pressure, and cholesterol under control
  • Quit smoking
  • Follow a healthy eating plan
  • Engage physical activity regularly
  • Maintain a healthy weight
  • Manage stress well
  • Get enough sleep

Coronary heart disease (CHD)

In CHD, a fatty substance builds up inside the coronary arteries that supply your heart with oxygen-rich blood. This results in narrowed coronary arteries and reduces blood flow to your heart muscle.

The fatty deposits also increase the likelihood of blood clots forming in your arteries, which either partially or completely block blood flow.

CHD can lead to chest pain, an irregular heartbeat, a heart attack or even death. CHD can also lead to heart failure by weakening the heart muscle over time.

Note that heart failure does not mean that your heart has stopped. It means your heart is unable to pump enough blood to meet your body’s needs, thus requiring medical attention.

Diabetic cardiomyopathy

Diabetic cardiomyopathy is a disease that damages the structure and function of the heart. This disease can lead to heart failure and an irregular heartbeat in people who have diabetes but do not have CHD.

How obesity increases your risk of high blood pressure

In obese individuals, the heart has to work extra hard to pump blood throughout the body, as a result of fatty substances accumulated in the arteries. This condition is called hypertension, where blood pressure on the inner walls of the arteries is very high. Individuals who experience abdominal obesity, where body fat is accumulated at the abdominal area, are likely to develop hypertension.

The link between diabetes and high blood pressure

Individuals with diabetes either do not have sufficient insulin to process glucose or have insulin that do not work effectively. Consequently, glucose cannot enter the cells to provide energy, and instead accumulates in the bloodstream. Blood with high glucose levels travels through the body and can cause harm to the blood vessels, making them targets for hardening, called atherosclerosis. If untreated, the blood vessel damage can lead to high blood pressure.

The link between high blood pressure and heart disease

Various heart disorders may occur when the heart consistently works under increased pressure.

Hypertensive heart disease is the number 1 cause of death associated with high blood pressure. It includes a group of disorders, such as heart failure, ischemic heart disease and left ventricular hypertrophy (excessive thickening of the heart muscle).

Ischemic heart disease

High blood pressure can cause ischemic heart disease, which is usually the result of a hardening of the arteries, otherwise known as coronary heart disease. This means that the heart muscle is unable to get enough blood as the pathway is blocked.

Left ventricular hypertrophy

Left ventricular hypertrophy is the enlargement and thickening of the walls of your heart’s main pumping chamber (left ventricle). The condition may develop due to high blood pressure or a heart condition.

In fact, high blood pressure is the most common cause of left ventricular hypertrophy. More than ⅓ of people show evidence of left ventricular hypertrophy when they are diagnosed with hypertension.

For your peace of mind, find out more about heart health or talk to one of our heart specialists today.


Article reviewed by Dr Ooi Yau Wei, cardiologist at Mount Elizabeth Novena Hospital.


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Ooi Yau Wei
Mount Elizabeth Hospital

Dr Ooi Yau Wei is a cardiologist practising at Mount Elizabeth Novena Hospital, Singapore.