A method is provided for reducing weight in a subject by administering an effective amount of a composition comprising omega-3 polyunsaturated fatty acid (PUFA), at least one of L-arginine, L-ornithine, an L-arginine precursor and an L-ornithine precursor, and at least one of a nucleobase, a nucleoside and a nucleic acid. The method can also be used to treat obesity, hyperlipidemia, diabetes and/or hypertension and for improving diathesis, or treating adult disease or disposition to adult disease.