Cardiovascular Disease and Weight

​​Introduction

Prevalence of Obesity 

Obesity is a major public health issue that is considered to be a leading cause of death globally. It is defined as an excess of fat storage and formation in the body and is a matter of concern due to its growing incidence, causing damage on a personal and wider economic level.

According to the World Health Organisation, more than 13% of adults were obese in 2016. In the UK, 1 in 4 adults and 1 in 5 children aged 10-11 are affected by obesity.1 The number of deaths caused by obesity exceeds those caused by being underweight. In addition, obesity is a risk factor for the development of many chronic health issues that could lead to serious complications that affect quality of life. Mental health issues may also arise as a consequence, such as depression, stress and the possibility of developing eating disorder behaviours.2 

In general, BMI (Body Mass Index) is used as a rough indicator of body fat. It is calculated using the weight and height of an individual, and may be nuanced with age and level of weekly exercise. A person is considered overweight when the BMI is greater than or equal to 25, while those who are obese will have a BMI equal to or greater than 30. A BMI chart can be seen below.3 

Chart showing BMI score using weight (x-axis) and height (y-axis). (Source: Patient.Info)3

However, it should not be used to diagnose obesity, as people with high muscle mass may have a high BMI. Thus, BMI should be used as an indicator and not a diagnostic tool for obesity.

Causes of Being Overweight

Diet

Becoming overweight occurs when calorie intake is consistently greater than the number of calories burnt.5 

Being mindful about your calorie intake can be challenging sometimes. The calories we need come from 3 main components of our food: protein, fat, and sugar. The amount of calories in each of the components varies, with fat having more caloric content than protein and sugar. Eating in a calorie surplus (more than your daily caloric requirement) will cause weight gain, and eating in a deficit than that will lead to weight loss. 

Choosing food rich in protein is important, as it contains fewer calories and makes you feel fuller for longer than sugary foods that give a lot of energy but wear off quickly. 

Genetics and Gut Microbiome

Recent studies have shown that obesity is not as dependent on external factors as we have previously thought. Genetics have a huge impact on one's susceptibility. Furthermore, research on gut microbiomes showed that people possess slightly different levels of 'good' and 'bad' microbes in the gut; thus, for many people, being overweight or obese is the result of a combination of factors – not just an inactive lifestyle and a bad diet.6

Physical Inactivity

Physical activity is any kind of sustained activity that works the muscles. These can be low intensity, such as walking or yoga, or high intensity such as running and lifting weights. Being inactive means that any excess energy from food will be stored as fat and contribute towards obesity. Staying active will keep you healthy not only physically but mentally as well.7 It is recommended to walk at least 30 minutes a day to reduce the risk of obesity-related health problems. 

Smoking

There is a belief that smoking is associated with weight loss, but recent studies have found that heavy smokers are more likely to gain weight. This may be because smokers tend to be less health-conscious.8 Smoking can also cause metabolic syndromes that could lead to central fat accumulation in smokers.9

Alcohol Consumption

Many people are unaware that alcohol has a lot of calories in it. One gram of alcohol has 7 calories and one unit of alcohol has 8 grams or 10 ml of alcohol, which comes to 56 calories. Excess drinking on top of eating a regular diet causes weight gain, as almost all kinds of alcoholic drinks are high in calories.10

How Does Weight Affect Cardiovascular Health?

Obesity is the most important risk factor that contributes directly to cardiovascular diseases among adults. Gaining weight means extra strain on the heart, and that may cause injury to the heart muscle itself or the vascular system as a whole.

Obesity can lower the levels of good cholesterol and increase the levels of bad cholesterol and triglyceride. Additionally, it increases blood pressure, as more blood needs to be supplied to cells in those with high body fat percentage. Overweight people are also more likely to have diabetes than those with normal body weight because obesity increases insulin resistance.8

Type 2 Diabetes

Type 2 diabetes is a health condition whereby the body is unable to regulate glucose levels in the blood. According to Public Health England, obesity is a major health factor that contributes to Type 2 diabetes. An obese adult is five times more likely to have type 2 diabetes than a healthy adult, and 90% of adults with type 2 diabetes are obese or overweight.11

The link between obesity and type 2 diabetes is not fully understood, but it is suggested that fat cells in the abdomen release chemical materials that make the body less responsive to insulin. Obesity can change the body’s metabolism, causing many inflammatory materials to be released, thereby increasing the body's resistance to insulin. 

Many symptoms of type 2 diabetes often remain silent but early signs include: a frequent need to go to the toilet, tiredness, thirst, losing weight without a clear reason, bad breath, and wounds taking more time than usual to heal. If untreated, diabetes can cause serious complications such as blindness, kidney problems, and nerve damage.

High Blood Pressure

Blood pressure is the force that the blood applies against the wall of a vessel. When that force is very strong, it is referred to as high blood pressure or hypertension. Its effects are not necessarily noticeable, and it is commonly referred to as the ‘silent killer’.

The measurement of blood pressure consists of two numbers: the numerator measures the force when the heart beats, and the denominator measures the force against the wall when the heart is in the rest position. A normal measurement is 110/70.

Obese individuals tend to have a high risk of hypertension compared to people with a normal weight because the heart is put under increased strain when pumping blood to the body. Sticking to an active lifestyle, reducing fatty and salty foods and drinking plenty of water can help control your blood pressure.12

As a precaution, measure your blood pressure regularly and consult your doctor if you notice a change. If the score is significantly high, you may witness some of the following symptoms: headache, nose bleeding, tiredness, or blood in the urine. Untreated high blood pressure can cause serious complications such as stroke, heart attack, heart failure, and kidney problems.

Heart Disease

Heart disease or cardiovascular disease (CVD) is a range of chronic diseases that involve dysfunction of either the heart muscle itself or the blood vessels or both. It can be reflected as a heart attack, stroke, angina, or coronary heart disease. Heart disease is a major cause of death globally. According to the WHO, heart disease kills 17.9 million people every year. A lot of risk factors play a key role in the development of cardiovascular disease – one of them being obesity.16

Obese individuals who follow an unhealthy diet tend to have a high level of cholesterol, causing fatty substances to stick to the vessel walls. When this happens, vessels are narrowed or even blocked, potentially leading to a heart attack.

The signs and symptoms of heart diseases include: chest pain, breathing difficulties, neck, jaw, and shoulder pain, tight feeling on the chest, fatigue, and cold sweats. Treatment ranges from medications to surgery according to the severity of the disease.

Stroke

A stroke happens when the oxygenated blood supply to the brain is reduced because of a blocked artery. This kind of stroke is called ischemic and it forms approximately 87% of all stroke cases.17  Another kind of stroke is called a hemorrhagic stroke which occurs when blood leaks from any of the brain’s arteries, which causes pressure on the brain. In both cases, the brain tissues will not get the oxygen it needs and start to experience potentially fatal damage.

There are many risk factors that increase the possibility of having strokes, such as obesity, alcohol, smoking, and lack of physical activity. The link between obesity and stroke is determined by the inflammatory effect of the fatty tissues that cause difficulties in blood flow within blood vessels. Due to hypertension also being a key cause of a stroke, there is also a strong positive relationship between obesity and high blood pressure.

According to the NHS, symptoms of a stroke mainly include: sudden headache, numbness, confusion, difficulty swallowing, and loss of consciousness.18 Changing to a healthy, active lifestyle and reducing alcohol intake are important prevention factors against a stroke.

Metabolic Syndrome

Metabolic syndrome is a mixture of health conditions that increases the risk of cardiovascular diseases. According to National Heart, Lung, and Blood Institute (NHLBI), to be diagnosed with metabolic syndrome, you must have at least 3 of the following factors:19

  • Accumulated fat in the stomach area (rather than any other parts of the body)
  • High triglyceride level in the blood
  • Hypertension (high blood pressure)
  • High blood sugar level

Recent research has indicated an association between obesity and metabolic syndrome, especially in the fat located in the waist area because it causes insulin resistance. Metabolic syndrome increases the risk of heart disease and diabetes.

Impact of Weight Loss on Cardiovascular Disease Risk

Losing weight can reduce the risk of developing cardiovascular disease. This can be achieved largely through lifestyle changes, such as: 

Diet

The most important key factor to maintain your weight is by following a healthy, balanced diet; it should be one that allows you to enjoy the food you love without gaining much weight. 

Taking into consideration your daily need for calories, ensure to have a balanced diet that incorporates foods such as lean protein, whole grains, a lot of fresh vegetables and fruits, low-fat dairy products, plenty of water, and foods rich in fibre. Try to avoid ‘empty calories foods’ – foods high in calories and low in nutritious value. Keep your diet in line with the NHS ‘Eat Well’ guide.

Make adjustments to your diet to focus on healthy fats such as olive oil and avocado (in place of butter and cream for example). Avoid sweets, cakes, and biscuits as snacks and replace them with fruits, vegetables, and raw nuts.

Exercise

Any kind of exercise could add up a great benefit to your body and mind. It only takes small changes to your daily routine, such as going on a daily walk, to see the health benefits of exercise.

It is recommended to do a mix of low-impact exercise like walking and strength training every week. Strength training could be activities such as weight lifting, using strength bands, or doing push-ups.

Quitting Smoking

Quitting smoking is a part of moving to a healthier lifestyle as it is a key risk factor for many diseases. Though it can be hard, it is achievable. Try to avoid the habits that trigger your cravings. Start by removing all tobacco from your surroundings. For support, you can contact your GP.21

By stopping smoking, you are improving the quality of your life, adding on extra years, as well as decreasing the risk of developing serious health conditions like CVD. 

Summary

Heart diseases are a group of health conditions that relate to the heart and contribute to your quality of life. As discussed, the main risk factor of heart disease is obesity. Having a poor diet and a sedentary lifestyle can contribute to becoming obese, although there are also genetic factors that can also equally come into play. Through a series of lifestyle changes, you can reduce the risk by adopting healthy habits, such as maintaining a healthy diet, exercising regularly, and quitting smoking.

References

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Randa Fahoum

Master's degree - Public Health, University of York, England
Randa is an experienced Dentist and Health Writer.
She wants to improve health and wellbeing across the globe.

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