Causes of Obesity and Bariatric Surgery

Obesity is a condition characterised by excessive fat accumulation in the body to an extent that impairs health. The causes of obesity include genetic predisposition, a sedentary lifestyle, overeating behaviours, and metabolic issues. For patients who cannot achieve lasting weight loss through diet and exercise alone, bariatric surgery stands out as one of the most effective medical options to step into a healthier life.

• Obesity is a chronic disease defined by a body mass index (BMI) of 30 or higher.
• Engaging with a television or smartphone while eating creates distraction, delays the feeling of fullness, and leads to excess calorie intake.
• Emotional eating triggers a craving for high-calorie foods during times of stress and anxiety, accelerating weight gain.
• Bariatric surgery is generally performed on individuals with a BMI of 35 or higher who also have obesity-related comorbidities.
• A multidisciplinary follow-up, including support from a dietitian and psychologist after surgery, is essential for permanent weight control.

What is Obesity and How Does it Develop?

Obesity is a chronic, progressive disease characterised by excessive fat storage resulting from an imbalance where energy intake exceeds energy expenditure. Far from being merely an aesthetic concern, it is a serious metabolic condition that affects all body systems. To maintain a healthy life, the body needs a certain percentage of fat; however, when this ratio exceeds 30 percent in women and 25 percent in men, clinical obesity emerges.

The conveniences of modern life have reduced our daily energy expenditure while making high-calorie foods easily accessible. Over time, this imbalance overworks the body's fat storage mechanisms. The accumulated fat tissue is not just a passive storage area; it actively secretes various hormones and chemicals that influence appetite, metabolic rate, and the immune system. This turns obesity into a self-feeding cycle.

What Are the Causes of Obesity?

It is difficult to pinpoint a single cause for the development of obesity. Usually, it involves a complex interplay of environmental, psychological, genetic, and hormonal factors.

Overeating Behaviours and Distracted Eating

Quickly consumed fast-food items, along with ready-made and processed foods, contain high amounts of sugar, salt, and saturated fats. The steadily increasing portion sizes of these foods inadvertently drive up daily calorie intake. Furthermore, an insufficient intake of fibre-rich foods prevents the stomach from feeling full.

In addition, being distracted during meals directly impacts overeating behaviours. When you eat while watching television, scrolling on your phone, or sitting at a computer, your brain cannot focus on the act of chewing and swallowing. This delays the satiety signals travelling from your stomach to your brain, causing you to continue eating even when you are full. Late-night snacking also adds an extra calorie burden during hours when the metabolism naturally slows down.

Emotional Eating and Psychological Factors

Intense emotions such as stress, depression, anxiety, and loneliness can drive people to use food as a coping mechanism. Emotional eating typically causes an irresistible craving for high-carbohydrate and sugary foods that provide momentary comfort. During stressful moments, increased levels of the hormone cortisol accelerate fat storage, particularly around the abdomen. For more detailed information on this topic, you can read our article on emotional eating.

Genetic, Hormonal, and Lifestyle Factors

A family history of obesity significantly increases an individual's risk. Genetic makeup directly affects the metabolic rate and the way appetite-controlling hormones function. Hormonal issues such as an underactive thyroid gland (hypothyroidism), insulin resistance, and polycystic ovary syndrome (PCOS) slow down the metabolism, increasing the tendency to store fat.

Inadequate sleep also disrupts the balance of ghrelin and leptin—the hormones that regulate appetite—leading to a greater urge to eat. Additionally, technological advancements have reduced the need for daily movement; desk jobs, the use of lifts, and a preference for private cars lower physical activity levels, paving the way for weight gain. Certain antidepressants, corticosteroids, and blood pressure medications can also cause weight gain as a side effect.

Symptoms of Obesity and Difficulty Losing Weight

The most obvious sign of obesity is an increase in body weight and waist circumference. However, as the disease progresses, various symptoms appear across different body systems. Experiencing difficulty in losing weight is a result of the metabolic resistance the body develops to protect its existing fat mass. Common symptoms include:

• Shortness of breath and quick fatigue, even during light physical activities
• Joint pain in the knees, lower back, and ankles due to excessive mechanical load
• Snoring and episodes of sleep apnoea during sleep
• Rashes in skin folds, fungal infections, and excessive sweating
• A constant feeling of hunger and cravings for sweets
• Menstrual irregularities and increased body hair

How is Obesity Diagnosed?

The diagnosis of obesity is made through comprehensive evaluations by specialist doctors in a hospital setting. The first step is calculating the Body Mass Index (BMI). BMI is obtained by dividing a person's weight in kilograms by the square of their height in metres; values over 30 indicate obesity. Measuring waist circumference is also a critical metric for assessing visceral (internal organ) fat.

Following a physical examination, blood tests are requested to identify any underlying metabolic or hormonal causes of obesity. Fasting blood sugar, insulin levels, HbA1c, thyroid function tests (TSH), liver enzymes, and a detailed lipid profile (cholesterol, triglycerides) are examined. Additionally, a body composition analysis thoroughly measures the ratio of muscle, fat, and water to create a highly personalised treatment plan.

Who is Eligible for Bariatric Surgery?

Bariatric surgery is not a cosmetic procedure, but a metabolic treatment aimed at preventing serious health issues. Therefore, it is performed on patients who meet specific medical criteria. The answer to who is eligible for weight loss surgery is based on the following criteria set by international health authorities:

• Individuals with a Body Mass Index (BMI) of 40 or higher (morbidly obese).
• Those with a BMI between 35 and 40 who also suffer from obesity-related comorbidities such as type 2 diabetes, hypertension, sleep apnoea, or severe joint disorders.
• Patients generally between the ages of 18 and 65 (in special circumstances, these age limits can be adjusted by a medical board decision).
• Individuals who have been unable to achieve lasting weight loss despite at least 6 months of medically supervised diet, exercise, and medical treatment.
• Those who have the psychological capacity to adapt to the necessary post-operative lifestyle changes.

Bariatric Surgery and the Treatment Process

The primary goal of bariatric surgery is to help patients shed excess weight, thereby curing or preventing obesity-related diseases. The surgeries are generally based on the principles of reducing stomach volume or decreasing nutrient absorption. The most commonly performed procedures include the sleeve gastrectomy and gastric bypass. Which method is right for you is decided together with your surgeon after detailed examinations. To learn more about the different methods, you can read our article on types of bariatric surgery.

Surgical interventions are usually performed using a closed (laparoscopic) method. This speeds up the recovery process and reduces the risk of pain and infection. The average hospital stay is between 2 to 4 days. After discharge, the dietary process begins with a liquid diet and gradually progresses to puréed and then solid foods under the supervision of a dietitian. Post-surgical weight loss significantly improves quality of life; patients' physical mobility increases, energy levels rise, and their social lives are positively impacted.

Complications Caused by Obesity and Risk Groups

When left untreated, obesity damages almost all organ systems in the body, leading to severe complications that can shorten lifespan. Excess weight exponentially increases the risk of cardiovascular diseases, heart attacks, and strokes. The process, which often begins with insulin resistance, eventually turns into difficult-to-manage type 2 diabetes.

Fatty liver disease, gallbladder issues, osteoarthritis (joint degeneration), and severe sleep apnoea are other common problems faced by obese patients. Furthermore, the risk of developing certain types of cancer, such as breast, colon, uterine, and prostate cancer, is significantly higher in obese individuals. Because of this, obesity is a public health issue that requires urgent treatment through a multidisciplinary approach.

When Should You See a Doctor?

If you are unable to lose weight despite your own efforts with diet and exercise, if you quickly regain the weight you have lost, or if your Body Mass Index has risen above 30, you should consult a healthcare facility. You should not waste time, especially if your weight restricts your daily life activities and negatively affects your mental well-being.

If you experience any of the following emergency warning signs, you should immediately call 112 (emergency services) or go to the nearest hospital's emergency department without delay:

• Pressure or a squeezing sensation in the chest, or pain radiating to the left arm or jaw (suspected heart attack)
• Sudden and severe shortness of breath that occurs even while resting
• Confusion, severe dizziness, or a feeling of fainting
• Sudden loss of strength or numbness on one side of the body (arm, leg, or face)

The Process at BHT CLINIC İstanbul Tema Hastanesi

At BHT CLINIC İstanbul Tema Hastanesi, obesity treatment is carried out through the collaborative efforts of the General Surgery, Endocrinology, Nutrition and Dietetics, Psychiatry, and Cardiology departments. When you visit our clinic, a detailed body analysis and blood tests are performed first. Patients scheduled for bariatric surgery undergo a comprehensive health screening beforehand to ensure they are prepared for the operation in the safest possible way.

After the surgery, support from a dietitian and psychologist continues uninterrupted to ensure long-term weight management. For any unexpected situations, our 24/7 emergency department and fully equipped intensive care units are always on standby. To get detailed information about obesity treatment and surgical processes, or to speak with our specialist doctors, you can call our call centre at 0850 811 34 00 or book an appointment via our website.

Frequently Asked Questions

Is bariatric surgery dangerous?

Every surgical intervention carries certain risks; however, the life-threatening risks posed by morbid obesity are generally much higher than the risks of the surgery itself. When performed laparoscopically by experienced surgeons in fully equipped centres, the complication rates for bariatric surgery are quite low.

Is it possible to regain weight after surgery?

Bariatric surgery is a powerful tool for weight loss, but it is not a miracle on its own. It is possible to regain weight if the recommended post-operative nutrition programme is not followed, if old unhealthy eating habits return, and if a sedentary lifestyle continues. Therefore, multidisciplinary follow-up is essential.

Does distracted eating cause weight gain?

Yes, watching television or using a phone while eating delays the brain's ability to perceive satiety signals. This distraction causes a person to consume far more calories than they need, leading to weight gain over time.

I am having difficulty losing weight; what could be the underlying cause?

If you cannot lose weight despite dieting, there may be underlying metabolic and hormonal issues such as insulin resistance, an underactive thyroid (hypothyroidism), polycystic ovary syndrome, or sleep disorders. You should consult an endocrinologist for an accurate diagnosis.

What is the age limit for bariatric surgery?

Bariatric surgery is generally performed on patients between the ages of 18 and 65. However, by evaluating the patient's general health, the severity of obesity-related comorbidities, and their capacity to undergo anaesthesia, surgery can also be performed on patients outside this age range following a medical board decision.

This article is for informational purposes only; please consult your doctor for diagnosis and treatment.