Why Can Being Full Make Future Hunger Seem Easier to Control?

Just after dinner, deciding to eat a smaller lunch tomorrow may seem effortless. At midday the next day, when hunger is intense, the same choice can suddenly become difficult. What has changed is not only willpower, but also the value that the current bodily state assigns to food.

Behavioural economist George Loewenstein described this cross-state misjudgement as the hot–cold empathy gap. A “cold” state does not mean having no emotion; it means that the relevant visceral drive is weak. A “hot” state may involve hunger, pain, intense anger or craving. In a cold state, people know they will later be hungry but often underestimate how hunger can narrow attention and increase the appeal of immediate satisfaction. Once in a hot state, they may instead treat the present desire as a stable preference and underestimate how much it will later subside.

This does not mean that bodily impulses inevitably defeat choice, nor does it excuse harmful loss of control. The research concerns average tendencies, and a short-lived laboratory state, a particular task and a particular sample cannot predict every decision made by one person. In one experiment with smokers, participants in a low-craving state underestimated the value they would place on cigarettes when craving was high. That supports state-dependent judgement, but it does not show that every desire operates with the same strength.

The real importance of the phenomenon is that it changes how we interpret a failed plan. A rule made in a calm state does not fully describe the future choice if it assumes that the future self will retain the present motivational structure. The sounder view is not simply, “I will use willpower when the time comes”, but to recognise that a future state can alter attention and value, and to avoid making the whole decision from scratch at the moment when the drive is strongest.

https://doi.org/10.1006/obhd.1996.0028
https://pmc.ncbi.nlm.nih.gov/articles/PMC2630055/