Eating patterns in patients recovering from major surgery—a study of voluntary food intake and energy balance

Abstract

Summary Voluntary food intake (VFI) and energy balance were studied in 12 adult patients over a 2-week period following elective colectomy. Daily VFI was recorded by weighing all food presented to the patient as well as any rejected by him or her. Home VFI was estimated by a dietary history technique. Energy balance was calculated from the VFI and from the changes in body fat and protein that occurred over the study period. The home VFI of the males was greater than that of the females with mean values of 2342 ± 542 kcal per day and 1666 ± 444 kcal per day respectively (mean ± 1 s.d.; P < 0.05). Eleven patients began to eat 2–7 days after the operation, reaching a maximum VFI in stepwise fashion between 7 and 14 days. The maximum VFI reached during this period was related to the home VFI (r = 0.84; P < 0.01). The twelfth patient required a second operation on the fifth postoperative day and began to eat 4 days later, reaching a maximum after a further 9 days. No simple relationship was found between postoperative VFI and energy output over the study period. The higher the energy output, the more energy was derived from endogenous fat and protein. An average energy deficit of 1155 kcal per day (range +197 to −2758) was observed, and there was no significant relationship between this deficit and the VFI, which averaged 949 kcal per day (range 371–1833). It is concluded that the amount of food consumed by post-surgical patients is dependent primarily on their previous home intake and not on their energy output. Patients with high energy outputs do not compensate by increasing VFI and large energy deficits can develop.