A study into the practice of trimming fat from meat at the table, and the development of new study methods
Background: Most food surveys do not take account of plate wastage, despite some evidence that fat intakes may be lower than is believed as a consequence of selective trimming of foods. Better study methods and more information about the trimming of food on the plate is needed.Methods: We studied 51 subjects (24 male and 27 female, aged 18–65 years) given a lunch-time meal composed of a tailed pork steak with boiled potatoes, peas and carrots. The pork steaks were weighed before consumption, as were any residual trimmings remaining after the meal. Each subject then completed a questionnaire which assessed trimming practice by two methods. The ‘photo-shading’’method required that a full-sized colour photograph of a pork steak be shaded with a fluorescent marker to denote the area which would be trimmed off. In the ‘photo-choice’ method subjects viewed four photographs of steaks trimmed to achieve fat reductions of 0, 35, 60 and 90%, and selected the photograph which most closely matched a steak that they would eat without further trimming. Pork steaks used for preparation of photographs and residual trimming following the 51 test meals were analysed for fat by the Soxhlet method. The shaded photographs were cut out and weighed, as was another photograph carefully separated into visible fat and lean tissue.Results: The average fat content of the pork steaks was 29.1 g/100 g. Fifteen of the 51 subjects did not trim the pork steak. Those who did trim the steak removed 4–73 g of tissue, the average fat content of which was 23 g. The effect of trimming was to reduce the average fat content of the steak (as eaten by ‘trimmers’) to 6.1 g/100 g (a 79% reduction). For the group as a whole (including non-trimmers) the fat content of the steak was reduced to 12.9 g/100 g (a 56% reduction). The average estimate of fat removed by ‘photo-shading’ was 14.9 g/100 g (8.3% lower than that obtained by direct measurement). The correlation coefficient of actual fat in the trim and fat in the trim predicted by photo-shading was 0.72. The photo-choice method proved less useful, only being able to distinguish the maximum trim group (90%) from the zero and 35% trim groups.Conclusions: Those who trim pork steaks remove a very high proportion (79%) of the fat present, and there was a good correlation between actual trimming practice and trimming assessed by the photo-shading method. We conclude that the photo-shading method may be useful for more extensive studies concerning meat trimming behaviour.