The high prevalence of obesity in our society makes obesity a major and increasing health hazard. Extensive observations pointed out a connection of obesity with a variety of illnesses. The evidence shows that obesity is a major contributor to the high prevalence of cardiovascular diseases, diabetes, hypertension, dyslipidaemia, gallstone disease, osteoarthritis and hyperuricaemia in the general population. Obesity also appears to be a contributor to cancers of the colon, prostate and rectum in men and breast, ovary, uterus and biliary tract in women. Hormonal abnormalities tend to occur in both obese men and women. Obese women have menstrual irregularities more often than nonobese. Obese persons tend to have reduced pulmonary function compared with nonobese. Although there are many unresolved issues, weight control is necessary for avoiding and reducing health implications of obesity. More information is required for controlling obesity and its consequences, prior to recommending a dietary advice and treatment.