The feasibility of broadband proton decoupled in uiuo I3C NMR spectroscopy of humans at 1.5 T was explored. A dual surface coil set-up was used, comprising a circular "C coil and a butterfly 'H decoupling coil placed at one third of its width away from the body. A calibration procedure was introduced to evaluate the specific absorption rate (SAR) in any gram of tissue for the inhomogeneous decoupling field generated by a surface coil. For the WALTZ-4 sequence it was demonstrated that broadband decoupled spectra of both subcutaneous adipose and underlying muscle or liver tissue could be obtained at 1.5 T without exceeding recommended maximum SAR values. Broadband decoupling caused an additional resolution enhancement ascribed to the removal of ('H-''C) long range couplings. Broadband proton decoupled spectra of subcutaneous adipose tissue were obtained in less than 10min showing highly resolved and intense signals of fully relaxed carbon spin systems of triacylglycerols. Broadband proton decoupled I3C NMR spectra of calf muscle showed several resonances for metabolites resolved from triacylglycerol signals (e.g. C,-C, of glycogen, C, of histidine, aromatic and carbonyl carbons of aminoacids and N l i k e d carbons of ethanolamine, choline and creatine). With an acquisition time of 20-30 min, the C, glycogen signal was observed with a root mean square signal-to-noise ratio of about 15. Not only the glycogen C, signal but also its C,-C, signals could be monitored in dynamic studies. Finally broadband proton decoupled "C spectra were obtained with signals from liver tissue (notably the carbons of glycogen). The localization of liver tissue from surrounding muscle tissue could be verified on the basis of the intensities of resonances typical of muscle tissue compounds. The signal strength of the liver glycogen C, signal was 2 to 3 times that of the glycogen C, signal of muscle after the same number of scans.