Non-invasive estimation of the fatty acid composition of adipose tissue using MRI or MRS may be valuable in a number of disease scenarios. However, in vivo validation against an independent gold standard is still needed. In this work, we find that especially MRI estimation of the fraction of saturated fatty acids is strongly associated to gas chromatography analysis in the adipose tissue of lymphedema patients. The reliability of the estimated mono- and polyunsaturated fractions are reliant on the used signal model. Also MRS provided results which are associated to GC analysis, but with a lower agreement compared to MRI.