Preface

Why is humanity in general becoming obese but some parts of the world are suffering from starvation? Ironically, this problem of socioeconomic disparity is becoming increasingly prevalent in almost every continent. Unfortunately, it is not an intended situation, such as health problems caused by being underweight. Obesity could be defined as a multifactorial and heterogeneous disease. Higher morbidity and mortality rates are associated with obesity. Excessive fat accumulation is seen as the etiological reason for almost all chronic diseases. Obesity threatens human health and reduces life expectancy. Genetic, biological, environmental, and behavioral factors (binge eating/drinking, laziness, lack of willpower, insufficient sleep, sedentary lifestyle, and self-indulgence) are blamed for the pathogenesis of obesity. Environmental factors (low socioeconomic status, lack of education, cultural reasons, and environmental pollution), family lifestyle, eating habits, and inactivity also play important roles in obesity. When biological factors (disability, gut microbiota, comorbidities, and prenatal, neural, and endocrine conditions) and genetics interact with behavioral and/or environmental factors, the result is obesity. Oxidative damage is the main underlying mechanism of obesity-related diseases. As the prevalence of obesity increases, morbidity and mortality from obesity-related diseases also increase. In addition, obesityrelated health problems increase treatment costs and lead to financial and labor losses in society. Population-based, preventive, and sustainable public health approaches are necessary to combat obesity. Obesity is preventable, and healthcare professionals have an important role to play in preventing this problem. Healthcare policy objectives must be centered on improving life expectancy and quality of life for humanity all over the world. Healthy and supportive environments are indispensable factors for preventing obesity, in addition to education. However, the fundamental issue is the processed food industry.

> **Hülya Çakmur** Kafkas University, Turkey

**1**

**Chapter 1**

*Hülya Çakmur*

it classifies as follows (kg/m2

**2. Obesity pathogenesis**

Introductory Chapter: Unbearable

Obesity and overweight are commonly accepted as immoderate fat accumulation in human body that increases the risk of almost every disease [1, 2]. Excessive fat accumulation is usually measured by body mass index (BMI), which is calculated with the weight and height proportions (weight relative to square of the height-w/h2

): <18.5 for underweight, 18.5–24.9 for normal weight,

[3]. A reliable measurement of the fat accumulation requires elaborated tool such as magnetic resonance imaging (bio-electrical impedance). Because of the Bioelectrical Impedance Analysis is not widely available, BMI is accepted populationbased definition and classification tool of obesity and overweight. Twenty percent and above fat accumulation in human body is accepted as normal [3]. If the level exceeds this limit (according to standard age, height, and weight tables), it is defined as overweight and obesity [3, 4]. BMI is a commonly used indicator of obesity and

25–29.9 for overweight, and ≥30 for obese [4]. Sometimes, BMI shows normal limits even in the presence of abdominal (central) obesity. So the central obesity, which is a kind of more risky obesity, could be hidden [4, 5]. It has been reported that almost half of the children and adults with excess body fat are defined as nonobese according to BMI [6, 7]. Underestimates of obesity prevalence could lead to less attention to problems and inadequate prevention and combat. Bioelectrical impedance uses tetra-polar measurements by touch electrodes and the measurements include broad spectrum from visceral fat mass to subcutaneous fat mass and body fat over [8]. Thus, misinterpretation of obesity and overweight can be prevented. Maximum attention is required to correct the evaluation of adipose tissue dissemination and

measurements. Health care professionals must be aware of hidden obesity.

The most widely accepted opinion about obesity pathogenesis is that it is the result of balance mechanism between energy intake and expenditure. Recent

investigation indicates that obesity pathogenesis is more complex than just an energy imbalance. The mechanism of energy intake and expenditure is a homeostatic process [9, 10–12]. This balance mechanism regulates body weight in "normal" limits. Earlier, obesity was thought just as an extreme calorie consumption than what the body needs. But researches and inventions in medicine show that the mechanism and etiology of obesity are not so simple. Reported studies showed that obesity pathogenesis is not only based on excess energy expenditure but also on the body's urge to fix and maintain the weight at an augmented value [9, 11, 13–15]. This process would explain why obesity does not respond to long-lasting diet and exercise program or why there is no permanent reduction in weight even if there is a response [12].

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Burden of the Diseases - Obesity

**1. Obesity definition measurement and classification**

### **Chapter 1**
