Effect of Prolonged Fasting on Olfactory Threshold

This study is concerned with two hypotheses: (a) prolonged fascing results in a change in olfactory threshold; and (b) thresholds are differentially affected for food-related stimuli and neutral substances. These hypotheses derive from studies reporting threshold changes after brief fascing and studies indicating effects of need on perception. Seventeen obese men averaging 312 lb., hospitalized for treatment of obesity, were kept on 0 to 300 calorie diets for periods of up to 3 mo., during which time weight loss averaged a pound a day per man. Olfactory thresholds for methyl salicylate (food-related) and benzene (neutral) were determined periodically by Jones' (1956) forced-choice sniffing technique, a method which eliminates the problem of differences in criterion among Ss and the errors of anticipation inherent in the traditional method of limits. Order of presentation of the two substances was randomized, and the two were separated in time by at least 15 min. For each substance, initial measurements were compared with determinations made after 1 wk., and after 1, 2, and 3 mo. of fasting. For seven Ss who changed from 0 to 300 calories, the last fascing mean was compared with the mean after a week of the 300-calorie regime. Not one of the 10 t tests yielded a value high enough for statistical significance or even high enough to warrant hope that a very large N following the same trend might produce values with statistical significance. Thus hypothesis (a) is not confirmed and hypothesis (b), which is dependent on hypothesis (a), is nor confirmed. The variability of thresholds obtained was no greater than might be expected in the course of repeated measurements without fasting, as indicated both by comparison with variability reported by Jones (1955) and by variability obtained in a group of six non-obese, non-fasting controls tested under the same conditions. Thus it does not seem reasonable to blame the lack of significant results on excessive variability. A more reasonable speculation is that effects reported by others may be specific to minor or brief deprivation rather than to prolonged extreme deprivation such as was experienced by these men, who counted the time since the last meal in weeks rather than in hours

Anticipation (artificial intelligence · Audiology · Calorie · Sniffing · Statistical significance · Internal Medicine · Medicine · Neuroscience · Olfactory and Sensory Function Studies · Psychology · Sensory Analysis and Statistical Methods

• Comparison between human olfactory sensitivity in the fasted and fed states

  Open Access•Haoyu Nie, Rong Zhao et al.•Appetite•2023

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