Twenty-four—hour pattern of hunger sensation in obesity complicated by type 2 diabetes mellitus: A pattern recognition by spectral analysis

Hunger sensation (HS) in humans physiologically shows intraday (circadian) and within-day (ultradian) recursivity. This intrinsic periodicity was investigated by applying the cosinor method and spectral analysis to the 24-hour profile of HS (orexigram) derived by a self-rating score (from 1 to 10 hunger units [HU]) recorded every half-hour. The study of circadian and ultradian recursivity on the orexigram was performed in 30 diabetic obese patients ([DOPs], 14 men and 16 women aged 22 to 62 years; body weight, 77 to 130 kg; body mass index, 31–47). The control group consisted of 30 clinically healthy subjects ([CHS], 15 men and 15 women aged 21 to 60 years; body weight, 65 to 72 kg; body mass index, 23 to 25). DOPs showed two types of orexigrams in which hunger was felt with limitation to the diurnal part of the day or with extension to the night, respectively. The type 1 orexigram was characterized by a normal spectrum and circadian rhythm. The type 2 orexigram was characterized by subsidiary ultradian components associated with an abnormal elevation of the circadian mesor and a significant delay of the circadian phase, as the spectral analysis was indicative of a structural difference in the frequencies that sustain the intraday and within-day recursivity of the HS. Accordingly, DOPs can be recognized by their orexigram as “eurectic” or “hyperrectic” to indicate subjects with a normal or an exaggerated HS, respectively, during the 24-hour span.