1H-MRS has been used extensively to measure the total amount of lipids stored in organs like skeletal muscle and liver and it has been found that these so called ectopic fat stores are associated with insulin resistance. The role of the composition of these lipid stores (e.g. saturated vs. unsaturated fatty acids) in metabolic disturbances is unclear. Here we show the feasibility of spectral editing techniques to characterize lipid composition in adipose tissue and skeletal muscle in vivo. Estimations of lipid composition with our approach are in line with invasive biopsy studies.