The invention is concerned with a method and a composition for treating or preventing catabolism or of stimulating anabolism in a mammal undergoing metabolic stress. The method comprises administering to the mammal a composition containing methyl donors selected from the group consisting of L-serine, methionine, choline, phosphatidyl choline, betaine, dimethylglycine, sarcosine, methylated folates, S-adenosyl methionine, thymidine triphosphate, adenosine triphosphate and optionally methyl acceptors selected from the group consisting of L-glycine, ethanolamine, phosphatidyl ethanolamine, folate, ribose, wherein the total molar amount of methyl donors delivered by the method exceeds the total molar amount of methyl acceptors delivered by the method by at least 0.18 mmol per kg of body weight per day.