Obesity is the condition of having too much body fat, this can lead to other health issues such as diabetes, cardiovascular diseases, and hypertension.
Obesity is the abnormal or excessive accumulation of body fat that can be detrimental to health. Obesity is often associated with, and increases the risk of metabolic diseases such as diabetes, cardiovascular diseases, high cholesterol, Polycystic ovarian syndrome, hypertension, and fatty liver disease.
What is obesity?
Obesity is a disease characterised by excess body fat or adipose tissue. This complex disease has multiple contributing factors, including genetics, neurohormonal, environmental, social, psychological, and behavioural factors. Bodyweight on its own may not indicate that you are obese, doctors often use several methods to assess body fat content and obesity.
BMI
Body mass index (BMI) is a simple tool to estimate a person’s body fat content based on their height and weight. BMI calculated using the following formula:
BMI (kg/m2) = weight (in kg)/height2 (in m2)
Obesity is classified as having a BMI of more than 30 kg/m2. However, in Asian or South Asian populations, obesity is classified as having a BMI of more than 25 kg/m2. This is because the proportion of Asian and South Asians at risk of type 2 diabetes and cardiovascular diseases is observed at a BMI of 25 kg/m2. However, it is also important to note that BMI does not reflect overall health as it does not take into account muscle mass or body composition. Dr Dinesh comments that BMI is usually accurate unless the individual is a sportsman/ lifter and has much of her/his weight bound to muscle. DEXA scans help differentiate obesity from healthy weight in these individuals. The common classifications of BMI are as follows:
Classification
BMI
BMI (Asian and South Asian)
Underweight
< 18.5 kg/m2
< 18.5 kg/m2
Normal
18.5 kg/m2 - 24.9 kg/m2
18.5 kg/m2 - 22.9 kg/m2
Overweight
25.0 kg/m2 - 29.9 kg/m2
23.0 kg/m2 – 27.4 kg/m2
Obese, class I
30.0 kg/m2 - 34.9 kg/m2
> 27.5 kg/m2
Obese class II
35.0 kg/m2 - 39.9 kg/m2
Obese class III
> 40.0 kg/m2
DEXA scans provide a detailed analysis of body composition, offering a more accurate assessment of fat, muscle, and bone mass than BMI alone.
Fat distribution
Waist circumference can also be used to assess obesity. Fat accumulation in the abdominal area, compared to the hips or lower body, is associated with an increased risk of type 2 diabetes, hypertension, and cardiovascular diseases. Typically, a waist circumference of 90 cm (35.4 in) in men, and 80 cm (31.5 in) in women is associated with an increased risk of these metabolic diseases.
What causes obesity?
Obesity is a multifactorial disease, and not due to ‘laziness or lack of discipline’. Obesity is now recognised as a disease that often requires long-term treatment. The causes/risk factors of obesity include:
Imbalance of energy intake and expenditure – Excessive intake of calories, while not being physically active (low energy expenditure) leads to weight gain and obesity. This is also often attributed to other factors such as social, economic, and environmental factors relating to food availability, food choices, and exercise habits.
Family history and lifestyle – Familial history of obesity can be attributed to genetics, lifestyle, and psychological factors. Scientists have linked about 250 genes to obesity, the most notable being the FTO gene in chromosome 16. Although genetic predisposition can contribute to obesity, it is important to note that genetics alone does not cause obesity. Obesity is nature vs. nurture (environmental factors).
Environmental factors such as eating and lifestyle habits from family members can also contribute to obesity. Studies show that risk factors of childhood obesity include parental obesity, snacking between meals, lack of sleep, and frequent consumption of sugary drinks. Childhood obesity is one of the strongest risk factors for adult obesity.
Gut microbiome – Obesity is associated with an altered gut microbiome. Our gut microbiome has several functions for metabolism of carbohydrates and lipids, synthesis of vitamins and amino acids, protection against diseases, and hormone regulation. An altered gut microbiome population is associated with diseases such as inflammatory bowel diseases, diabetes, and obesity. This is likely a symptom of poor nutritional choices and lifestyle rather than a cause of obesity as modifying the gut microbiome has not been shown to improve weight.
Hormonal dysregulation – Hormones can also influence obesity risk. Leptin is a hormone responsible for appetite and energy balance regulation, leptin resistance in obese patients can contribute to increased appetite and hunger, leading to eating more and gaining more weight. Additionally, fatty tissues in the body release adipokines and free fatty acids, which can also lead to inflammation and insulin resistance, further contributing to obesity and subsequent metabolic disease.
Obesity is a chronic disease and is not caused by one independent factor, but rather a combination of different factors which can take effect over a long period of time.
Obesity is a major risk factor for non-alcoholic fatty liver disease (NAFLD), highlighting the urgent need for proactive metabolic and liver health management.
Cardiovascular diseases – Excessive fat accumulation in the walls of our blood vessels (atherosclerosis) can lead to an increased risk of cardiovascular diseases including heart attack and stroke. Additionally, the fatty tissues in the body also release inflammatory cytokines. The resultant inflammation can accelerate atherosclerosis.
Type 2 diabetes – Obesity is linked to the development of insulin resistance, which can consequently lead to prediabetes and subsequent type 2 diabetes.
Chronic kidney disease (CKD) – Obesity increases the risk of CKD due to an increased risk of diabetes and hypertension, both of which are risk factors for CKD development. Obesity can also damage the kidneys directly and cause obesity-related nephropathy.
Hypercholesterolaemia – Excess of fat tissues in the body can leads to increased insulin resistance and subsequently an increase in triglycerides and a decrease in high density lipoprotein (HDL, the so-called good cholesterol) in the blood. The resultant ”Atherogenic dyslipidaemia” which is characterised by high triglycerides and low HDL leads to an increased risk of atherosclerosis, cardiovascular diseases, and strokes.
Hypertension– Adipose tissues are secretory organs that can influence other systems of the body. Obesity can lead to hypertension via several mechanisms, which include overactivation of the sympathetic nervous system (SNS), stimulation of the renin-angiotensin-aldosterone system, and alterations in adipose tissue cytokine production.
Non-alcoholic fatty liver disease (NAFLD) – NAFLD is a liver disorder in people who drink little to no alcohol caused by an excess build-up of fat in the liver. This can cause damage to the liver and subsequent permanent scarring (cirrhosis). Dr Dinesh noted that NAFLD is predicted to be the number one cause of liver failure in the future as the rate of obesity increases.
Certain cancers – Obesity is also a risk factor for several types of cancer, including breast cancer, colon cancers, kidney cancers, oesophageal cancers, and endometrial cancers. Obesity likely increases the risk of cancer through chronic inflammation mediated by adipokines, and alterations in endogenous hormone metabolism.
Respiratory diseases – Asthma and obstructive sleep apnoea are among the most common respiratory complications related to obesity. Obesity can cause breathing difficulties due to a restricted airway, inflammation, and hormonal changes. At extremes of body weight, it can even cause respiratory failure (Obesity hypoventilation syndrome).
Osteoarthritis – Osteoarthritis is caused by the degeneration of the protective cartilage that surrounds the bones of the joints. Obesity is a risk factor for osteoarthritis, as the excess body weight can wear out the joints faster. Inflammation associated with obesity has also been implicated in other forms of arthritis, such as rheumatoid arthritis. Dr Dinesh notes this is a frequent issue that limits weight loss. Weight gain causes sore joints that prevent exercise. This causes further weight gain and further osteoarthritis. This may be an indication for pharmacotherapy to break the weight gain cycle.
Obesity can also negatively affect a person’s self-perception and self-esteem, leading to psychological issues such as depression and anxiety.
How is obesity managed?
As obesity can cause multiple other complications, treatment and management can vary according to patients. Dr Dinesh commented that it is important to treat obesity as a real medical condition. Patients have often already tried to lose weight through dietary means and exercise and failed because of neurohormonal changes that prevent further weight loss. It is not because of lack of effort or self-motivation that weight is difficult to control. And even if that is indeed the case, it is only one of many reasons why weight has been difficult to control.
Lifestyle modification
Lsifestyle modification is the initial mainstay of obesity management. In order to lose weight and maintain your weight, changes to your diet and lifestyle are important. Dr Dinesh is a huge advocate for exercise and fitness but he also admits that 80 percent of weight loss is from calorie restriction (diet).
Diet – Dietary changes to help in weight loss include cutting calories, substituting foods for lower calories options that are satiating (keep you full). Satiating foods that include whole grain foods, lean protein, low-calorie but voluminous vegetables can help in regulating hunger.
Exercise – Exercise is important in losing weight. Generally, people with obesity are recommended to do 150 minutes of moderate intensity exercise every week. You may increase the intensity or duration as you get used to being more physically active. Time-poor individuals will have to incorporate exercise into their daily lives (incidental exercise). Those who haven’t exercised previously will have to start small to prevent injury. A mixture of cardio and resistance training is important in achieving this goal.
Lifestyle modifications or changes may be challenging at first, hence it is important to consult your doctor and healthcare team to ensure that the changes you make are sustainable while meeting your needs. Unfortunately in some these measures can fail but lifestyle change is the first and most important initial phase of weight control and needs to be achieved prior to other methods being used.
Anti-obesity medications
Anti-obesity medications are typically given to obese patients, or overweight patients with comorbidities, who struggle to lose weight through diet and exercise alone. It is important to note that these medications work synergistically with a healthy diet and regular exercises.
GLP-1 Agonists
Dr Dinesh prefers GLP-1 agonist medication in weight loss when required especially if diabetes or NAFLD is present.
GLP-1 reduces gastric motility and therefore physically causes increased satiety. In addition it decreases neurotransmitters that cause hunger and therefore reduces cravings. Our body tries to defend a set-point when it comes to weight which results in weight loss failing over time when done conservatively in some individuals and ‘yo-yo’ weight loss. GLP-1s reduce this set-point. It is important to note that just like cholesterol or high blood pressure, obesity, especially when unable to be managed conservatively, is a chronic disease. Just like how stopping cholesterol or blood pressure medication, stopping a GLP-1 medication will result in you returning to your old set-point.
GLP-1 receptor agonists are medications that help regulate blood sugar and support weight loss by mimicking the effects of the body’s natural incretin hormone.
Summary
Obesity is a multifactorial and complex chronic disease characterised by excess body weight and fat accumulation. Thankfully, in some it is also a reversible condition when addressed with the right lifestyle modifications, such as a balanced diet, regular physical activity, and consistent behavioral changes.
It’s important to understand that weight loss isn't always just a matter of willpower. In some cases, underlying biological factors may make weight loss more challenging, and medical intervention becomes a necessary part of your journey. At The Metabolic Clinic, we believe that with the right support and treatment plan, sustainable weight loss is achievable. The key is to take the first step by understanding your body.
Obesity can impact your life expectancy as it increases the risk of various non-communicable diseases such as cardiovascular diseases, diabetes, hypertension, and even some types of cancer. While obesity may not be the cause of a reduced life expectancy, complications of obesity can increase the risk of life-threatening events such as strokes or heart attacks.
Can you inherit obesity?
Scientists have found several genetic components to the cause of obesity. While you may have a genetic predisposition to obesity, it is often not enough to cause obesity. In some cases, dietary or lifestyle habits acquired from family, as well as genetics, can contribute to obesity.
Is long-term treatment with GLP-1 agonists harmful?
In patients with diabetes, the converse is true, there were reductions in heart disease, stroke and kidney disease in randomised-controlled weight. There is no evidence that GLP-1s are harmful and the weight loss will probably improve medical comorbidities and outcomes though longer-term studies in the non-diabetic patient population are ongoing to confirm this.
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