Obesity is a global epidemic with increasing number of individuals becoming overweight. World Health Organization (WHO) has called obesity a preventable disease mainly because most obese patients benefit by changing food habits and lifestyle. It is very well established that obesity increases the risk of several life threatening diseases like insulin resistance, diabetes, atherosclerotic vascular disease (CVD), cancer, chronic inflammation, bone disorders etc. Several natural products like herbs, dairy products, and products from marine organisms have been reported to have anti-obesity properties. These products reduce obesity by influencing different pathways such as decreasing intestinal absorption, fatty acid synthesis, adipocyte differentiation as well as increasing intestinal transit, beta oxidation, and metabolic rate. In this chapter, we have compiled information about the use of different natural products as anti-obesity agents and how they affect body weight.