Obesity is considered a serious global health issue. Patients have been predisposed to comorbidities such as dyslipidemia, cardiovascular diseases, diabetes, cancers, and osteoarthritis. Certain fats in the diet have been linked with an increase in obesity, such as saturated and trans-fats. Meanwhile, some dietary fats such as conjugated linoleic acids (CLAs) and medium-chain triglycerides (MCTs) could potentially reduce energy intake. Various mechanisms for reducing weight by CLAs and MCTs, such as increased lipolysis, improved intestinal microbiota, up-regulating peroxisome proliferator-activated receptors (PPARs), increased the expression of uncoupling protein of respiratory chain-1 (UCP-1), and affected satiety hormones are included. These bioactive compounds, CLAs and MCTs, should be used in moderate concentrations to prevent harmful effects such as insulin resistance for CLAs and hypercholesterolemia for MCTs. However, several studies have proposed CLAs or MCTs as adjuvants to the protocol used to minimize bodyweight. Our objective is to summarize the different causes of obesity and to discuss the effects of CLAs or MCTs on body weight and fat deposition in obese animals or humans.