The following thesis describes a gradual approach of a diet therapy process using a practical example. According to the referring diagnosis “gastrectomy” the relevant parameters are collected and the dietary measures planned. All subsequent decisions are taken on the basis of specialist literature theories and thus should be considered as evidence based. The focus of the study is put on the avoidance of malnutrition due to the limited digestive activity, in particular by avoiding the dumping syndrome. The weekly menus, based on specified target values can be considered as an example of an adequate nutritional therapy. Their aim is the full coverage of demand as well as avoidance of all possible complications for this particular patient. The essential conclusion of this work is that alimentary coverage of Vitamine D demand is not possible. Apart from that, the demand for iron cannot be covered temporarily. Nevertheless, the extensively adequate nutrition through systematically chosen food and appropriately matched size and frequecy of meals is documented.