CORRECTION OF DIETARY-FAT AVAILABILITY ESTIMATES FOR WASTAGE OF FOOD-SERVICE DEEP-FRYING FATS

Because of the renewed interest in the consumption of hydrogenated fats, reliable estimates of the dietary fat available to the United States population require correction for the considerable amount of deep-frying fats used in food service operations that are discarded after use and thus are not available for consumption. We estimated this fat wastage from food service sources from published data on fat exchange during cooking and on numbers of specific entrees purchased away from the home by United States households. Among food items considered, fat rendered from hamburgers and chicken contributed substantially to the total gross fat available for discard; fried chicken, french fries and doughnuts accounted for a large portion of total fat uptake by foods. To calculate waste frying fat, expressed as a percent of net waste fat, we subtracted fat uptake by foods from the total visible frying fat available for usage and from the level of gross fat available for discard. Dividing the resulting values gave a percent waste frying fat of 60%. For calculation of fat available for consumption, we recommend that contributions from deep-frying fats be reduced by 50% of the total available to correct for wastage. This value is conservative and representative of actual experience of major food service operations and agrees closely with estimates derived from spent grease recovery reported in the United States.