Does hunger go away on its own if you ignore it?
Research shows that hunger hormones remain active during a calorie deficit, regardless of whether you ignore the feeling. Structured fasting appears to trigger fewer binge-eating episodes than daily calorie restriction.
Hunger does not go away on its own if you ignore it. The body responds to a calorie deficit with hormonal changes that actually keep the feeling of hunger going. People who consistently eat less see their leptin levels drop. Leptin is the hormone that makes you feel full; less of it means the signal 'I have eaten enough' becomes weaker.
Ghrelin, the hormone that triggers hunger, does fall slightly with fasting regimens. That sounds positive, but the effect is small. What is more, hunger is far from gone as a result: in a twelve-month study, the hunger hormone levels of people who fasted three fixed days a week were barely different from those of people who ate less every day. At no point in time was there a meaningful difference. So one dietary pattern does not make you less hungry than the other.
What does differ is what hunger does to your behaviour. With daily calorie restriction, uncontrolled eating increased over twelve months. In the fasting group it decreased. This suggests that constantly pushing hunger aside on a regular diet becomes counterproductive over time: the risk of binge eating grows. Structured fasting appears to partly sidestep that pitfall, but through behaviour, not through hormones.
In practical terms this means: ignoring hunger does not resolve itself, and persisting for a long time without a strategy increases the risk of uncontrolled eating. Anyone wanting to lose weight or stick to a diet is better off choosing the approach that carries the lowest risk of binge eating, rather than hoping the feeling of hunger will simply disappear.
This answer draws on two sources: a summary of many studies into the effect of fasting regimens on hunger hormones, and a twelve-month study in which fasting (three fixed fasting days per week) was compared with daily calorie restriction. The summary of many studies shows that the hormonal effects are measurable but small; the twelve-month study adds that the behavioural effect is larger and more practically relevant than the hormonal effect. The evidence is reasonably solid regarding the direction of the effects, but the long-term consequences of the hormonal shifts have not yet been well studied.