Disclosed are induced viscosity nutritional emulsions comprising (A) protein having a protein-bound methionine sulfoxide content of 8% or less of the total protein-bound methionine, on a molar basis, (B) fat, and (C) an induced viscosity fiber system that provides the emulsion with a packaged viscosity of less than 300 cps and an induced viscosity following consumption of at least 300 cps, wherein the induced viscosity nutritional emulsion is an oil-in-water emulsion. It has been found that product stability is improved and shelf-life increased by selection of those protein sources having a low methionine sulfoxide content.