Six methods of assessing individual food intake reported by telephone were compared for accuracy. A sample of 107 students eating in a dormitory dining hall was used. Two 7-day and four 3-day diet records were reported by telephone to either an interviewer or an answering device; and fourteen 6-h recalls and seven 24-h recalls were obtained by an interviewer over the telephone. To examine validity, the investigators observed respondents' intake for 28 days. Food item agreement scores comparing observed and reported data were calculated. Seven-day records were most accurate (87% food item agreement); 3-day records and 6-h recalls were equivalent (75%); and 24-h recalls were least accurate (69%). There were no significant difference in accuracy of reporting records to an interviewer versus a recording device, but respondents preferred the interviewer. Results of telephoned reporting compare favorably with personal interview techniques used by other investigators, indicating that telephoned methods should be further explored in community settings.

The validity of a food frequency questionnaire for dietary assessment was tested with 31 college students living and dining in a dormitory. A food frequency questionnaire was mailed to participants requesting them to estimate their usual intake of specific food items. Actual food consumption was determined at each meal with self-report forms. These forms required participants to indicate foods chosen at that meal. To test the validity of the frequency questionnaire, regression equations were calculated for each individual using the frequency questionnaire data as the independent variable (X) and actual intake data as the dependent variable (Y). Eighty-four percent of the r values were greater than 0.50 and 55% were greater than 0.71. All were significant at the 0.002 level or below. As an alternative test of validity, the percentage of over- and underestimation of each food group was also assessed. Foods which are often major components of a meal (eg, flesh foods) were estimated with greater accuracy than those foods which could be considered accessory (eg, nuts or seeds). While it appears that a large percentage of individuals could accurately estimate their intake with this technique, some individuals were unsuccessful in doing so. Further research is needed to identify individual characteristics which may predict success with this technique.

Rats consuming a diet of 34% tallow select more protein and less carbohydrate than rats fed either 5% corn oil or tallow or 34% corn oil (25). To examine potential mechanism(s) of this phenomenon, we fed rats diets containing either tallow or corn oil at levels of 5 or 34% for 2 days. Sera were analyzed, and rats fed 34% tallow had higher serum insulin compared with those fed 34% corn oil. In a second experiment, rats were fed either 34% corn oil or tallow for 2 days. Brain tissues were analyzed, and rats fed 34% tallow had elevated serotonin in the raphe area compared with those fed 34% corn oil. In a third experiment, rats were fed either 34% corn oil or tallow for 2 days and then given dl-fenfluramine before diet selection. Fenfluramine depressed food intake to a greater degree in rats fed 34% tallow compared with those fed corn oil. These findings suggest that the diet selection behavior observed in tallow-fed rats may be mediated by a central serotonin system.

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Recombinant human tumor necrosis factor-alpha (rHuTNF) was injected into rats to test its reported cachectic effects. Rats were subcutaneously injected daily at 1730 hr with either saline or rHuTNF (0.25 mg/kg body wt) for either 5 or 14 days. Daily food intakes were significantly depressed only for the first day and first two days of rHuTNF injection in animals treated for 5 days and 14 days, respectively. There were no significant differences in daily body weights among the groups. Analysis of carcass composition revealed no significant differences in percentage of lipid or protein. Liver and inguinal pad weights were not significantly different. In vitro determination of lipogenesis showed it was enhanced in the inguinal pad and depressed in the liver only after 14 days of treatment. These results demonstrate that although in vivo rHuTNF may specifically alter tissue metabolism, it does not, by itself, result in a sustained cachectic effect.