Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, such as increasing the likelihood of heart disease, diabetes, obstructive sleep apnea, and osteoarthritis. Obesity is most commonly caused by a combination of excessive food energy intake, lack of physical activity, and genetic susceptibility. It is one of the most serious health problems of the 21st century, especially in those highly developed countries, with increasing prevalence in adults and children. Chapter 1 presents results of a systematic review of school-based interventions that incorporated a nutrition component designed to prevent childhood obesity. Chapter 2 shows the association between overweight and obesity in school age children and their parents. Chapter 3 points out that high calorie intake and/or low physical activities reflecting in high or low body mass index, abdominal circumference, blood pressure and heart rate are not dependent on wealth and level of education. Chapter 4 presents high prevalence rate of obesity in Serbian preschool children, particularly for girls, where preschoolers with high aerobic fitness during kindergarten years have less total and abdominal adiposity than their unfit counterparts. Chapter 5 offers new strategies to treat obesity in both children and adults by using hormones. The hormones leptin, ghrelin and obestatin are known to affect the development of obesity. Chapter 6 aims to link an evolutionary perspective on the modern obesity crisis to a rationale for a treatment outlined in Brazil. Chapter 7 discusses the linkage between mortality rate and obesity, as well as the relationship of obesity with physical activity and dietary habits. Chapter 8 discusses the plasma homocysteine level with lifestyle factors like diet, alcohol intake, smoking habit and body weight, in a cross section of population. Chapter 9 describes the molecular mechanisms and attenuating strategy for sarcopenic obesity. Sarcopenic obesity is a medical condition where a person shows an increase in fat mass and a reduction in lean mass. Chapter 10 focuses on the role of renal sodium transport in hypertension associated with insulin resistance. Chapter 11 proposes possible roles of a novel ATPase, Atp10c/ATP10C, in metabolic pathways of insulin signaling and glucose uptake. Chapter 12 presents gastric bypass surgery, which has been performed on more than one million patients suffering from morbid obesity. Chapter 13 summarizes all the anesthetic and technical aspects on managing the obese patients. Chapter 14 discusses the latest advances in the biology of brown adipose tissue and how its activation may serve as an efficacious therapy to control body weight gain. Chapter 15 shows herbal drugs are very much effective in the conditions and has no side effects after long uses, in which the principles of the Ayurvedic Science, like increasing property (i.e., snigdha property) and decreasing property (i.e., rukshya property), are very much useful in the treatment of disease like Obesity, Hyperlipidemia, etc. Chapter 16 investigates the effect of a combination consisting of curcumin with piperine and quercetin (CPQ) on obesity. It shows that it exerted significant anti-obese activity due to its Hypophagic, Hypoglycemic and Hypolipidemic effects.