Obesity - symptoms, causes, diagnosis

: Weight gain
abnormal fat accumulation
Limited physical performance
Hyperhidrosis
Heartburn
Sleep apnea
Increased risk of secondary diseases

: genetic disposition
psychosocial factors
Physical inactivity
over-energy
Medication
Metabolic diseases
Sleep deprivation

: Physical inactivity
over-energy
psychological disorders
psychological stress
radical changes in one's life

: Nutritional therapy
Behavior modification
Exercise Therapy
surgical procedure
Medication

: Orlistat

(iStock / Liudmila Chernetska)

Grundlagen

Obesity is a chronic, treatable condition in which body fat increases beyond normal levels. The word is derived from the Latin "adeps" (fat). The disease affects numerous bodily functions and increases the risk of disease and death. The body mass index (BMI) is often used for weight classification. The body mass index (BMI) is formed from the quotient of weight and height squared (kg/m2). A BMI of 30 kg/m2 or more is considered obesity. So-called extreme obesity is present from a BMI of 40 kg/m2.

Basics

The body mass index

Since the exact measurement of body fat is often difficult, the BMI is often used for obesity classification. However, BMI does not provide any information about a person's body fat percentage.

Category	BMI	Risk of concomitant diseases
Underweight	< 18,5	low
Normal weight	18,5 - 24,9	average
Overweight	≥ 25
Preadiposity	25 - 29,9	somewhat increased
Obesity grade I	30 - 34,9	increased
Obesity grade II	35 - 39,9	high
Obesity grade III	≥ 40	very high

Frequency

In Austria, about one third (34.5%) of people are currently overweight and 16.6% of the population is affected by obesity. In Germany, the figures are somewhat higher. Here, about half of the population is affected by overweight and about a quarter of adults are obese (24%). The incidence of obesity generally increases with age, with two-thirds of those affected not developing obesity until adulthood. However, in recent years, an increase in obesity has been observed in young adults and also in women of childbearing age. Obesity is less common overall in individuals with high socioeconomic status.

Causes

In obesity, the body gets a surplus of energy in the form of food, while at the same time too little energy is consumed in the form of exercise. This surplus usually exists for a long period of time and is stored in the fat cells of the body. Genes, hormones, lifestyle, psychological factors and also the environment play a role in the development of the disease. The increase in the incidence of obesity is currently attributed primarily to fattening environmental factors. These are characterized by overeating, a lack of exercise, and the consumption of highly processed foods.

The following are possible causes of obesity:

genetic causes
familial disposition
high food availability
lack of sleep
stress
depression
low social status
Eating disorders (e.g. binge eating disorder)
Metabolic disorders (e.g., hypothyroidism, Cushing's syndrome)
Medication (e.g., antidepressants, neuroleptics, beta-blockers)
Other causes (e.g. immobilization, pregnancy, smoking cessation)

The western diet

The modern diet in industrialized nations, compared to the diet of our ancestors, has an energy density that is about 2 to 3 times higher. This is the result of a higher density of "fast food" products and highly processed foods with a lot of fat and sugar. The fiber content of these products, on the other hand, is usually low. Since the feeling of satiety also depends on the distension of the stomach, the feeling of satiety is triggered later when such energy-dense foods are eaten. This circumstance favors increased calorie intake. In recent years, the average portion sizes of fast food products have also increased, as a result of which people often consume a larger amount of food. Children, adolescents and young adults nowadays also consume high-sugar soft or energy drinks more often, which can greatly increase the risk of obesity if consumed regularly.

Fixed or regular mealtimes also prevent obesity. However, many people nowadays eat on occasion or even spontaneously (so-called snacking), which makes it more difficult to control energy intake. Often, spontaneous eating also tends to involve fast food or so-called "convenience" products.

The influence of daily life

Many factors of daily life influence the occurrence of obesity. For example, desk jobs and long commutes to work can make access to physical activity more difficult. In addition, in urban areas, there are often few opportunities for running, cycling, or even other sports. Education, educational level, and housing also influence the risk for obesity. In general, obesity occurs less frequently in people with academic education and high household income than in people with low socioeconomic status.

Symptoms

The symptoms of obesity are varied and depend, among other things, on the age of the person affected, concomitant diseases and the severity of the obesity. Typical conditions include dyspnea, frequent back pain, and varicose veins.

(iStock / towfiqu ahamed)

Complications of obesity

Obesity is considered an important risk factor for a variety of diseases. According to the WHO, obesity is responsible for about 44% of all cases of diabetes and about 23% of all cases of coronary heart disease worldwide. In addition, it is estimated that obesity is causative for about 7 - 41 % of all cancers. In Germany alone, obesity-associated diseases cause total annual costs of around 10 - 20 billion euros.

Diseases for which obesity is a significant risk factor:

Diseases of the musculoskeletal system (e.g., knee osteoarthritis)
Gallstones (cholecystolithiasis)
Fatty liver (steatosis hepatis)
Gout (hyperuricemia)
Increased blood fat levels (hyperlipidemia)
High blood pressure (hypertension)
Heart failure (cardiac insufficiency)
Neurodegenerative diseases (e.g. dementia)

Risk of comorbidities according to WHO:

Risk > 3-fold increased	Risk about 2 - 3-fold increased	Risk 1 - 2-fold increased
Diabetes (type 2 diabetes)	Coronary heart disease	Cancer
Gallstone disease	Hypertension	Polycystic ovary syndrome
Elevated blood lipid levels	Knee joint osteoarthritis	Hip osteoarthritis
Insulin resistance	Gout	Back pain
Fatty liver	Reflux esophagitis	Infertility
Sleep apnea syndrome		Fetopathy

Problematic abdominal fat

Visceral fat in the abdomen is not simply present, but can be considered like an organ in its own right. It is metabolically active and produces hormones as well as other substances that promote inflammation throughout the body. In addition, these hormones weaken the immune system. Thus, the body is constantly fighting chronic inflammation, which promotes the onset of high blood pressure, diabetes, and heart disease, among other conditions. For example, adipokines are signal molecules that are increasingly produced in human adipose tissue and are involved in the development of type 2 diabetes mellitus or atherosclerosis.

From a BMI of ≥ 25 kg/m2, the waist circumference should therefore always be measured in those affected. This allows the visceral fat to be assessed. Waist circumferences of ≥ 88 cm in women and ≥ 102 cm in men indicate abdominal obesity with a significantly increased risk of developing obesity-associated diseases.

Stigma and discrimination.

Obesity has a variety of psychosocial implications. In recent years in particular, there has been an increased focus on the stigma and discrimination that often accompany the condition. In the Western world, obesity is usually viewed negatively, and studies in Germany have also shown that obese people are devalued. Many people assume that people develop obesity due to laziness, lack of discipline and weakness of will. This prejudice should be questioned, since from the current medical point of view many factors and also physical diseases can promote the occurrence of obesity.

Diagnosis

The following diagnostic steps are necessary or recommended for an obesity evaluation:

Medical history	Onset and development of overweight Possible influencing factors Motivation of the person concerned for treatment Family history Nutritional history Recording of physical activity
Physical examination	Height, weight, BMI Circumference of the waist Blood pressure with possible long-term blood pressure measurement Determination of resting energy consumption
Laboratory diagnostics	Blood count, electrolytes, creatinine, transaminases Lipid status Blood glucose, possibly HbA1c value Oral glucose load test TSH basal (at initial examination)
Imaging procedures	ECG Cardiac ultrasound Upper abdominal ultrasound

In particular, the attending physician should also inquire about the patient's diet or physical activity. This is usually done with a free protocol, questionnaires or a pedometer. Differential diagnoses of obesity include bulimia nervosa or binge eating syndrome.

Treating physicians should always ask about other metabolic risk factors such as elevated blood lipid levels ( hyperlipidemia ), diabetes mellitus, and high blood pressure (hypertension) during the medical history.

Secondary obesity

In about 1 - 5 % of obesity sufferers, the overweight occurs in the course of secondary obesity. These should be ruled out prior to obesity treatment.

Possible underlying diseases that can trigger obesity include:

hormonal changes
hypothyroidism (underactive thyroid gland )
Cushing's disease
benign tumors of the pancreas with insulin secretion
Central nervous changes
neoplasms or damage to the hypothalamus

In addition to diseases, drugs can also be involved in the development of obesity. These include, in particular, antidepressants (e.g., mirtazapine), neuroleptics (e.g., clozapine, olanzapine), hypnotics, antiepileptic drugs (e.g., gabapentin, valproic acid), steroids, antihistamines (e.g., ranitidine), oral antidiabetics, and insulin.

Therapy

Nowadays, there is a wide range of therapeutic options to treat obesity, prevent secondary diseases and improve the overall quality of life.

The most important goals of obesity therapy are:

Prevention of secondary diseases
Maintenance of metabolic health
Treatment of existing underlying diseases
Destigmatization
Promotion of body awareness
Promotion of self-confidence

Treatment goals in obesity therapy are always individual and should always be agreed with the person affected. In the case of obesity without concomitant diseases, the goal is usually a weight reduction of 5-10% with subsequent weight stabilization. However, the amount of weight loss targeted also depends on the concomitant diseases of the affected person. For example, in patients with an existingdiabetes (diabetes mellitus type 2), a weight reduction of about 5 - 15 % is recommended. The subjective improvement of the quality of life always has a high priority in the treatment of obesity patients.

A combination of a moderately hypocaloric diet, exercise, and behavior modification is currently recommended as standard therapy for obesity. If these measures do not achieve a 5% to 10% weight reduction in 3 - 6 months, intensification of therapy - e.g., with a highly restrictive caloric intake in the form of a low-calorie diet - should be considered.

BMI and waist circumference as therapy indication

BMI alone is not sufficient as a criterion for indicating obesity treatment and must often be expanded to include waist circumference. In this context, waist circumference is suitable as a measure of the fat distribution pattern. Waist circumferences of ≥ 88 cm in women and ≥ 102 cm in men are associated with a significantly increased risk (relative risk 2-4) for metabolic and cardiovascular diseases.

Gesunde Kost (iStock /vaaseenaa)

Nutrition therapy

The goal of nutrition therapy is a negative energy balance. Patients should still experience a feeling of satiety through the calorie-reduced diet in order to be able to establish the form of therapy in daily life in the long term. Low-fat foods as well as plant foods with a high fiber content are to be preferred here. The composition of the macronutrients (fat, protein, carbohydrates) is not decisive.

A clever choice of foods - lower-energy foods, fruits and vegetables - can usually achieve energy savings of 500 to 800 kcal per day. In doing so, the amount of food can often be maintained, allowing sufferers to continue to have a good feeling of satiety.

Another simple measure is to limit fat intake. Here, instead of 80 - 130 g per day, 60 g of fat per day should be supplied. This concept is relatively easy to implement, as those affected only need to focus on the intake of one macronutrient. This measure often leads to a weight loss of 3 to 5 kg and it is particularly suitable for weight stabilization as well as for obesity primary prevention.

Behavior modification

Methods of learning and behavioral psychology are suitable for practicing healthy eating behavior and lifestyle. For example, triggers for food intake can be analyzed and identified. Unfavorable behavioral patterns related to food intake can also often be changed with professional psychological help. It is recommended to decouple food intake from external factors and to set rules for meals as well as for food shopping. Group interventions are also suitable for changing eating behavior and are often more successful than individual sessions.

Exercise therapy

Exercise has other positive effects on the body besides increasing energy expenditure. Every obesity sufferer should therefore be encouraged to increase regular exercise activity. Sport or physical activity also has the advantage of preserving muscle mass during dieting, which also improves the long-term results of weight loss.

Exercise can increase the body's calorie consumption. In addition, the appetite decreases through sports and stress regulation also works better. For many people, various sports are a stabilizing social event, and sports have a particularly positive effect on the cardiovascular system, which is often affected by obesity. Ideally, one should exercise at least three to five times a week for 30 minutes. Attention should also be paid to achievable goals, because it is better to exercise less regularly than to hold irregular intensive training.

The type of sport is secondary, although endurance sports are usually more beneficial than strength sports. Since obesity patients are often untrained, regular sports should be performed only after a medical examination. The load intensity can then be gradually increased, although overloading should be avoided at all costs due to the increased risk of injury in obesity.

Medication

Medications should always be seen as a support to a lifestyle change and should always be combined with it.

Possible agents for the treatment of obesity are:

Active ingredient	Mechanism of action	Common side effects
Orlistat	Lipase inhibitor (inhibits fat absorption in the intestine)	flatulence, bloating, fatty stools
liraglutide, semaglutide	GLP-1 receptor agonists (inhibit appetite and slow gastric emptying)	Nausea, vomiting, diarrhea, constipation
Naltrexone/bupropion	Opioid antagonist/norpinephrine dopamine reuptake inhibitors ( release of anorexigenic hormones, inhibition of reward center)	Nausea, vomiting, dizziness, headache, constipation, insomnia, flushing, hypertension, dry mouth, fatigue

Bariatric surgery

In the case of bariatric surgery, patients must always be carefully informed about the risks and consequences of the operation, as the risk of surgery is greatly increased in the case of existing obesity.

The indication for surgery is usually only given for a BMI of over 40. With a BMI of over 35, surgery can be considered if concomitant diseases make rapid weight reduction necessary or all other attempts at therapy have failed.

In principle, these surgical interventions attempt to reduce the volume of the stomach. This results in a limited food intake, which in turn leads to weight reduction.

The various procedures include:

Gastric Banding: A silicone band is placed around the stomach and then filled with fluid as needed. This reduces the entrance to the stomach and allows only small amounts of food to be ingested.
Vertical gastroplasty: part of the stomach is separated by staple sutures and secured by a silicone band.
Gastric balloon: A balloon is inserted into the stomach and filled with more or less fluid as needed. This method is rarely used today.

However, for a permanent reduction in body weight, eating habits should also be changed and optimized. In addition, those affected usually continue to require intensive internal, nutritional and psychological care after surgery. Micronutrients such as vitamins and trace elements often need to be supplemented after bariatric surgery.

Forecast

For many people with severe overweight, losing weight without professional help is almost impossible. The body registers a significant weight loss and then tends to return to the initial weight (so-called yoyo effect). This is based on evolutionary biological mechanisms. In early human history, severe weight loss was life-threatening and much more dangerous than weight gain or even obesity.

Obese people have a shorter life expectancy than people of normal weight. The younger the person, the greater the correlation between BMI and mortality risk. A BMI of 30 to 35 kg/m² shortens life by about two to four years on average. A BMI of 40 to 45 kg/m² even reduces people's life expectancy by eight to ten years. This shortened life expectancy is caused by obesity-associated secondary diseases. In older age, however, the correlation between BMI and mortality risk decreases significantly.

In most cases, permanent weight reduction can only be achieved through long-term treatment concepts with medical support. It is advisable not to fixate on a certain desired weight, but to lead a healthier life overall through a permanent change in lifestyle. This helps to lose excess weight slowly but permanently and in a healthy way. A high level of self-motivation on the part of patients is also useful here and greatly increases the success rate of obesity therapy.

A diet should therefore not be primarily goal-oriented, but should be seen as a lifelong and balanced change in diet. It is advisable to optimize it so that it is healthy and tastes good at the same time. Because only then it is permanently feasible. Optimally, this healthier diet should be combined with regular physical activity.

Prevent

Even small phases of increased physical activity during the day can help prevent obesity.

To lose weight or maintain one's own weight, attention should be paid to a low-fat and high-fiber diet. Foods with a low energy density are particularly suitable for this purpose. These have fewer calories because they are rich in water and fiber. Snacks, fast food and sugary or alcoholic beverages should be avoided as far as possible.

Sources

Dr. med. univ. Moritz Wieser

Thomas Hofko

Obesity (adiposity)