Subjective hunger relationships with meal patterns in the spontaneous feeding behavior of humans: evidence for a causal connection.

The relationship between the subjective state of hunger and objective food intake was investigated using a diary self-report method. Thirty-one adult humans were paid to record in a diary, for 7 consecutive days, everything that they either ate or drank, the time that they ingested it, and how hungry they were on a seven point scale. The diary entries were encoded and entered into a computer. Meals were identified according to 5 different definitions and meal compositions, estimated stomach contents, and intermeal intervals calculated. Univariate and multiple linear regression predictions of self-reported hunger and meal size were calculated from these data. Self-reported hunger was found to be related negatively to the energy content and the proportion of protein in the stomach at the time of meal ingestion. Meal size was also found to be related to these same factors and also positively to self-rated hunger. These results suggest that protein has a unique satiating property beyond its contribution to total food energy. When self-rated hunger and the premeal stomach contents were all used in a multiple regression prediction of meal size the premeal stomach contents influence became nonsignificant leaving subjective hunger as the only significant predictor of meal size. These results suggest that subjective hunger represents an intermediary step in the cause-effect sequence between gut filling and cessation of meal ingestion.