Highly palatable foods induce a dopamine-mediated reward response that is activated during stress or negative affect.

Study: Bed nucleus of the stria terminalis connectivity during food cue and taste processing under stress

When people are stressed, their brain changes how it responds to tasty foods — this study shows that stress makes key brain areas linked to pleasure and reward react differently to those foods, which may explain why we crave them when we're upset.

Study: Stress-driven potentiation of lateral hypothalamic synapses onto ventral tegmental area dopamine neurons causes increased consumption of palatable food

When mice are stressed, their brain strengthens a pathway that makes them crave and eat more tasty, fatty food—this happens because stress boosts dopamine, the brain's 'reward' chemical. So yes, eating yummy food when upset is linked to a real brain reward system that kicks in during stress.

Study: Palatable-Food-Driven Top-Down Circuit Inhibits PVNCRF Activity to Mitigate Stress Via Peri-PVNCRFR1 Neurons.

When people eat tasty foods, their brain releases dopamine, which calms down stress signals in the brain—this study found exactly how that happens in mice. So eating comfort food isn’t just a feeling—it’s your brain’s real way of coping with stress.

Study: Sex-dependent effects of chronic stress on reinstatement of palatable food seeking and involvement of dopamine D1-like receptors.

When rats were stressed, they started trying harder to get tasty food, and this only happened when their brain's dopamine system was active — showing that stress makes the brain crave tasty food through the same reward pathway that makes us like sweets.