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Obesity has now become a global crisis, and rates have been dramatically increasing. In the UK it's estimated that around 1 in every 4 adults and around 1 in every 5 children aged 10 to 11 are living with obesity (1).
Obesity is primarily diagnosed through Body Mass Index commonly known as BMI. Your BMI is easy to calculate and correlates with body fat percentage and body fat mass. However, it is important to note that BMI does not distinguish between fat and lean mass (muscle, bone, water). Some people for example athletes may have a high BMI but low body fat (2).
The World Health Organisation (WHO) define overweight as having a body mass index (BMI)>25kg/ m2 and obese individuals having a BMI >30 kg/m.
You can use the NHS BMI healthy weight calculator to find out your BMI.
For most adults, if your BMI is:
- Below 18.5 – you're in the underweight range
- 18.5 to 24.9 – you're in the healthy weight range
- 25 to 29.9 – you're in the overweight range
- 30 to 39.9 – you're in the obese range
- 40 or above – you're in the severely obese range
Obesity is associated with many health conditions but one of the most serious associations is with heart disease. Obesity isn’t always just about carrying extra weight there is a direct and indirect link between obesity and heart disease. Not only does it have an impact on heart disease but also increases the risk of other conditions that may harm the heart.
How much does obesity increase the risk of heart disease?
Obesity is more than just a number on the scale; it can have serious effects on your heart health. Let's break down how carrying excess weight can raise your risk of heart disease and what’s happening inside your body when this occurs.
What happens to your heart when you’re obese?
When excess body fat, especially around your waist builds up, it’s not just harmless padding. It can actively disrupt your health and put a strain on your heart and blood vessels which seriously increases the risk of heart disease.
The extra weight can lead to the build-up of fatty materials inside your arteries. These arteries are the highways that carry oxygen-rich blood to your organs. When they get clogged, this condition is called atherosclerosis and it's dangerous. This is one of the main factors causing the direct link between obesity and heart disease (3).
Atherosclerosis makes it harder for blood to flow freely, increasing your risk of:
- Heart attacks
- Irregular heartbeats (arrhythmia)
- Heart failure
Understanding the link between Obesity and Heart Disease
To understand the link between Obesity and Heart Disease, it is important to know the pathways in which excess body fat can lead to cardiovascular dysfunction. So how does obesity cause heart disease risk?
Obesity is linked to other conditions that indirectly raise your risk of heart disease including:
1. Type 2 diabetes
According to Diabetes UK - around 90% of people with newly diagnosed type 2 diabetes are living with overweight or obesity.
It is important to state that insulin resistance can develop because of obesity. This is a condition where the body stops responding to insulin and often shows up before the type 2 diabetes diagnosis and is commonly seen in those with obesity. Insulin resistance can also play a role in the formation of fatty plaques in the arteries which leads to cardiovascular issues (4).
2. High blood pressure
When you carry extra body fat, your heart must work harder to keep up. That’s because fat tissue needs more oxygen and nutrients, so your heart pumps more blood to meet the demand.
Over time, this puts extra strain on your heart and can lead to high blood pressure. If left unchecked, high blood pressure can damage your arteries and make it easier for fatty deposits to build up inside them. This can slow down or block blood flow raising your risk for heart attacks and other serious heart problems (5).
3. High Cholesterol
The main cause of high cholesterol is often lifestyle-related, and obesity can play a significant role in elevating your cholesterol. Your body naturally produces low density lipoprotein (LDL) cholesterol known as the "bad" cholesterol, but an unhealthy lifestyle can cause your body to produce more LDL cholesterol than it needs.
Excess LDL cholesterol can build up as fatty deposits along the walls of your arteries. This buildup narrows the arteries and increases the risk of heart disease (6).
4. Kidney disease
Obesity can significantly accelerate the progression of kidney disease; this increased risk is often linked to the higher prevalence of type 2 diabetes and high blood pressure in people with obesity. Additionally, excess body fat can directly affect kidney function through inflammation and changes in kidney structure, further increasing the risk (7).
Each of these health conditions can arise due to obesity, as a result this puts additional strain on your heart and blood vessels, creating the risk for serious cardiovascular problems.
What’s going on with fat tissue?
Fat in your body, also called adipose tissue, isn't just sitting there. It actually acts like an organ, helping regulate your energy and immune system. In healthy people, this works smoothly.
But in people with obesity, fat tissue starts behaving differently. It becomes inflamed and begins to release harmful proteins called cytokines, like IL-6 and CRP.
These proteins cause more inflammation, and that can lead to:
- Insulin resistance (a key factor in diabetes)
- High blood pressure
- Damage to blood vessels
We have differing types of fat with the body, many people worry about the fat they can feel that sits directly under the skin known as subcutaneous fat. However, the bigger health risk comes from visceral fat. Visceral fat is the fat that sits around our internal; organs such as the heart and liver. This can influence both the heart and blood vessel function (8).
How to manage Obesity and Heart Disease to prevent the risk of complications
With obesity comes an increased risk of heart disease and/or heart complications. The first step to managing this risk is through maintaining healthy weight loss.
Diet
The most crucial factor in any weight loss plan is the ability to create and sustain a calorie deficit over the long term. Research shows that no single diet is inherently more effective for weight loss than another; the key is finding one that you can consistently follow and maintain over time.
An example of a balanced meal should ideally consist of:
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To improve the risk of heart disease in relation to what you're eating, you can start with including certain foods. Heart-healthy eating involves choosing certain foods, such as fruits and vegetables, while limiting others, such as saturated fats and added sugars.
Examples include:
- Veggies: Leafy greens (spinach, kale, collard greens, cabbage), broccoli, carrots
- Fruits: Apples, bananas, oranges, pears, grapes, prunes
- Whole Grains: Oats, brown rice, whole-grain bread or tortillas
- Dairy: Fat-free or low-fat milk, cheese, yogurt
- Protein: Omega-3 rich fish (salmon, tuna, trout), lean meats (skinless chicken, turkey, 95% lean beef, pork tenderloin), eggs, tofu, nuts, seeds, legumes
- Healthy Fats: Olive, canola, sesame, sunflower, safflower, corn, or soybean oil; walnuts, almonds, pine nuts, nut butters, seeds (pumpkin, flax, sesame, sunflower), avocados
Exercise
Being active is important for managing your weight and improving heart health. Combing a healthy diet and regular exercise is key to maintaining a healthy weight. Exercising can also give your more energy, lower anxiety and stress, help you to get better sleep and even boost your mood! (9)
The NHS recommends that adults (aged 19-64) should aim to:
- Do strengthening activities that work all the major muscle groups (legs, hips, back, abdomen, chest, shoulders and arms) on at least 2 days a week
- Do at least 150 minutes of moderate intensity activity a week or 75 minutes of vigorous intensity activity a week
- Spread exercise evenly over 4 to 5 days a week, or every day
- Reduce time spent sitting or lying down and break up long periods of not moving with some activity
- To begin with you may think this is unachievable however daily exercise could look like
- A 10 minute walk 3 times a day, ideally this could be after each meal; breakfast, lunch and dinner.
So, how does obesity cause heart disease
Overall, the connection between obesity and heart disease is both direct and indirect but can cause serious health complications. Excess body fat in particular visceral fat places strain on the heart causing it to work harder. This contributes to risk factors such as high blood pressure, high cholesterol and inflammation. These factors lead to damage within the blood vessels and arteries therefore causing the increased risk of serious cardiovascular events such as heart attacks, heart failures and heart disease. Preventing and managing obesity through lifestyle change is essential for individual well-being but also for reducing the broader burden of heart disease worldwide.
References
- https://www.nhs.uk/conditions/obesity/
- https://digital.nhs.uk/data-and-information/publications/statistical/health-survey-for-england/2022-part-2/adult-overweight-and-obesity?
- https://www.bhf.org.uk/informationsupport/risk-factors/obesity
- Kahn, B. B., & Flier, J. S. (2000). Obesity and insulin resistance. The Journal of clinical investigation, 106(4), 473–481. https://doi.org/10.1172/JCI10842
- https://www.ahajournals.org/doi/10.1161/CIRCRESAHA.116.305697
- https://world-heart-federation.org/what-we-do/cholesterol/
- https://www.kidneyresearchuk.org/kidney-health-information/about-kidney-disease/am-i-at-risk/obesity-and-kidney-disease/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC10421666/
- https://www.nhs.uk/conditions/coronary-heart-disease/prevention
