Hunger

Hunger is the perception of individual’s typical hunger level.  Hunger reflects a person’s stable underlying sensistivity to hunger feelings and predisposition to eat.

Hunger scores  are positively associated with energy intake. Being chronically hunger makes individuals more susceptible to overeating, when compared with individuals do not report being often hungry. Correlations between hunger and disinhibition tend to be high when correlation between hunger and restraint tend to be low. Hunger is common in younger individuals than older individuals. It is also suggested that women might be more aware of their biologic signals of hunger and consequently they are maybe more responsive to their inner cues.

Ghrelin is one of the gastrointestinal hormones with its putative orexigenic function and is mainly produced by gastric cells prior to food intake. Langlois et al. showed that ghrelin is associated with self-reported perception of hunger, independently of anthropometric measures and lifestyle. They reported that in lean people, ghrelin regulates hunger signaling and energy intake. In contrast, increased BMI seems to be associated with lower ghrelin levels and disrupted association between ghrelin levels and hunger feelings.  Also, in their cohort study, obese teenagers had  higher ghrelin levels and reported a greater food intake than their lean counterparts. Therefore, they hypotized that ghrelin could be implicated in early obesity development (childhood and adolescence) by increasing hunger signals and energy intake, but once body weight has reached a certain point, chronically increased ghrelin levels are down-regulated, explaining the observation of lower ghrelin with higher BMI as observed in their cohort and in previous reports in obese adults. 

Although hunger has a homeostatic component, it has also a hedonic part. Overeating is originated from this hedonic part of hunger.  Hedonic hunger favors energy-dense palatable food, rich in sugar and fat, for example snacks, pastries, desserts, baked confectionery and sweets which foods typically ingested in between meals and preferred by women. Regardless of energy status, the anticipation of pleasure causes hedonic eating. The hedonic hunger is constituted by two components, wanting and liking. Wanting represents the anticipation phase, the motivation to eat a food item, and is triggered by cues. Liking is the hedonic reaction of the pleasure experienced through a rewarding orosensory stimuli.

In a study, thylaakoids supplementation reduces feelings of hunger and increases feeling of satiety by affecting subjective ratings of appetite. It also reduces wanting for palatable food. Furthermore, the treatment effect on wanting and liking is correlated to reduction in food intake. In addition, liking for sweet is reduced after consumption. It is suggested that these effects are due to altered secretion of appetite regulating hormones, induced by the thylakoids, affecting reward-related areas in the brain.