Dietary fatty acids serve as an important source of energy, as well as providing critical components of cell membranes. Our choices of dietary oils impact the blend of fatty acids ultimately consumed which, in turn, appear to affect the rate at which we metabolize these various fats. This presentation will focus on the research for weight loss including the medium chain fatty acids coconut oil, conjugated linoleic acid, diacylglycerol, and the monounsaturated fats including olive oil and canola oil. For long chain fatty acids, some research showing that n3 polyunsaturated fatty acids (PUFA) undergo preferential oxidation for energy compared to other fatty acids, suggesting weight loss possibilities for marine oils. In summary, the research presented in this lecture will demonstrate that not all fats are created equally but that some dietary fat categories are preferentially utilized for energy production leading to weight loss.