What Really Controls Appetite and Hunger: Science Behind Food Cravings and Eating Habits

Knowing the difference between hunger and appetite, and understanding the sensory cues behind them, can help us make better decisions about what we eat

Imagine you’re in a meeting room when someone brings out the biscuits – a packet of Jammie Dodgers, perhaps, or a nice little plate of custard creams. Maybe you want one and maybe you don’t, but the chances are the people around you are all responding differently: someone will grab a couple straight away, someone else will eat one without seeming to notice, another will barely be aware the biscuits exist, and someone will spend the whole meeting wanting one but not taking it. Our appetites and responses to food vary wildly – but what’s going on behind the scenes to govern them? And has modern food somehow hijacked the process? Grab a biscuit (or don’t) and settle in.

“First, it’s important to distinguish between hunger and appetite,” says Giles Yeo, a professor of molecular neuroendocrinology at the University of Cambridge and the author of Why Calories Don’t Count. “Hunger is a feeling – it’s what happens in the run-up to you deciding you need to eat something. Appetite is everything that surrounds why we eat – including hunger, fullness and reward, or how you actually feel when you eat. Those three sensations all use completely different parts of the brain, but they all work together.”

Hunger arises from physiological signals indicating energy need, primarily regulated by the hypothalamus and brain stem integrating neural and hormonal inputs from the periphery. This homeostatic system ensures eating occurs when the body requires fuel, driven by hormones such as ghrelin and leptin that communicate energy status to the brain.

Appetite, in contrast, encompasses a broader range of influences including emotional states, environmental cues, learned habits, and the brain’s reward pathways. Hedonic hunger—eating for pleasure rather than energy need—can override homeostatic signals, particularly when triggered by foods high in sugar, fat, or salt, which activate dopamine-driven reward circuits.

The gut-brain axis plays a central role in regulating both hunger, and satiety. Signals from the gastrointestinal tract, including mechanical distension and nutrient sensing, are transmitted via the vagus nerve to the brainstem and hypothalamus, modulating feelings of fullness and reducing further food intake. This bidirectional communication helps terminate meals and delay the return of hunger.