Food compositions which comprise, as an active ingredient, an extract of migratory fish or a mixture of nutritional components of a similar composition to the above-mentioned extract in an amount of 0.5 g or more per one meal of the extract or the mixture in terms of the solid content thereof are effective for treating and/or preventing stress and stress-related conditions. With such food compositions it is possible to prevent or alleviate states such as fatigue e.g., asthenopia, mental fatigue, emotional dysfunction and the like, caused by stress and felt on a daily basis.