What Is Obesity?

Obesity is a medical condition in which a person has an excessive amount of body fat that increases their risk of health problems.

While it is often associated with body weight, it is more accurately understood as a metabolic and hormonal disorder that influences energy use, appetite, and fat storage.

What Causes Obesity?

Obesity is usually assumed to be a result of too much fat in the body due to eating too much and moving too little. However, it is actually more complex than that.

Body weight is regulated by a network of hormones and metabolic processes. When these systems are disrupted, the body may store more fat, slow down energy use, or increase hunger signals.

One of the key drivers is insulin resistance, where the body becomes less responsive to insulin and starts storing more fat, particularly around the abdomen.

Certain medical conditions can also contribute to the problem. For example, hypothyroidism can slow metabolism, while polycystic ovary syndrome may affect weight through hormonal imbalance and changes in insulin sensitivity.

Lifestyle factors still play an important role. A combination of biological, behavioural, and environmental influences—such as diets high in processed foods and sugar, lack of physical activity, poor sleep, and chronic stress can all contribute to weight gain. Genetics and age-related changes in metabolism may also make some individuals more prone to gaining weight than others.

In most people, obesity develops from a combination of these factors rather than a single cause.

Symptoms and Diagnosis of Obesity

There are no specific symptoms of overweight and obesity. Your healthcare provider may diagnose overweight or obesity based on your medical history and an elevated Body Mass Index, also known as BMI.

It is calculated by dividing your weight in kilograms by your height in meters squared.

However, BMI is only a screening tool. It does not distinguish between fat and muscle, nor does it reflect how fat is distributed in the body. In clinical practice, doctors may also assess waist circumference and recommend blood tests to evaluate metabolic health. These tests can help detect early changes in blood sugar, cholesterol levels, and thyroid function.

Risk Factors

Obesity is usually the result of several overlapping factors rather than a single cause. The key risk factors may include:

• Eating high-calorie or processed foods
• Drinking beverages that are high in sugar
• Poor sleep
• Chronic stress
• Family history of obesity
• Hormonal conditions such as hypothyroidism or PCOS
• Certain medications

Complications (Health problems caused by obesity)

Obesity is a chronic condition that can affect nearly every organ system in the body. People who are overweight or obese are at greater risk of developing chronic diseases such as:

Type 2 diabetes mellitus

Type 2 diabetes mellitus occurs when blood glucose levels become too high. Many individuals with type 2 diabetes mellitus are overweight or obese. Over time, raised blood sugar can lead to serious complications such as heart disease, stroke, kidney damage, vision problems, and nerve damage.

Losing just 5 to 7 percent of your body weight can significantly reduce your chance of developing type 2 diabetes mellitus.

Hypertension

High blood pressure, or hypertension, occurs when blood flows through the vessels with excessive force.

If left untreated, it raises the risk of heart attack, stroke, and kidney disease. Reaching a healthy weight can help lower blood pressure and reduce these risks.

Sleep apnoea

Sleep apnoea is a common condition in which the upper airway becomes blocked during sleep, causing irregular breathing or brief pauses in breathing.

If left untreated, sleep apnoea increases the risk of heart disease, diabetes mellitus, and other serious health problems.

Fertility problems

Hormonal balance can also be affected. In men, it is linked to lower sperm count and reduced sperm quality. In women, it can disrupt the menstrual cycle and ovulation, making it harder to conceive or carry a pregnancy to term. Obesity may also reduce the success of certain fertility treatments.

Treatment and Management Options

Managing obesity is not about quick fixes or extreme dieting. Instead, the focus is on improving overall health in a sustainable way.

Lifestyle modification

A structured lifestyle plan focuses on sustainable, realistic changes rather than extreme dieting.

Balanced nutrition: Reducing daily intake by about 500 to 750 calories can support gradual weight loss of 0.5 to 1 kg per week. As a general guide:

• Women: around 1,200 to 1,500 calories per day
• Men: around 1,500 to 1,800 calories per day

Focus on vegetables, fruits, whole grains, and lean proteins such as fish, poultry, tofu, and beans. Limit sugary drinks, fried foods, and large portions.

Exercise: Aim for at least 150 minutes of moderate activity weekly, such as brisk walking, cycling, or swimming. Include strength training two to three times per week to maintain muscle mass.

Even a 5 to 10 percent weight loss can significantly improve overall health.

Behavioral support

Counselling or structured programs can help address emotional eating, stress, and long-standing habits.

Medical therapy

In selected cases, prescription medications may be used to support weight loss under medical supervision.

Surgical options

For individuals with severe obesity or obesity-related complications, bariatric surgery may be considered after careful evaluation.

Importantly, treatment plans should be personalised, taking into account medical history, lifestyle, and long-term goals.

When Should You See a Doctor

You should consider seeking medical advice if you:

• Have a BMI in the overweight or obese range
• Experience breathlessness or joint pain
• Have a family history of diabetes mellitus or heart disease
• Notice rapid or unexplained weight gain
• Struggle with weight despite conscious lifestyle efforts

Early assessment can help identify underlying causes and prevent more serious complications from developing over time.