The Sunlight and Serotonin Connection
The primary driver behind this craving is your brain's reaction to the weather. Reduced exposure to sunlight on overcast, rainy days can cause a dip in your levels of serotonin, often called the “feel-good” neurotransmitter. [11, 18] Serotonin is crucial
for regulating mood, appetite, and feelings of well-being. [5] When its production slows, your brain instinctively seeks ways to get it back up. This is where sweet and starchy foods come in. This can also be linked to lower levels of Vitamin D, which our bodies produce in response to sunlight and which also plays a role in mood regulation. [8, 11]
Carbohydrates as a Quick Mood Fix
Carbohydrates, especially the simple sugars found in pastries, chocolate, and other sweet treats, provide a rapid solution for low serotonin. [2, 4] Research from MIT has shown that consuming carbohydrates (without much protein) triggers the release of insulin. [5, 16] This insulin helps clear out other amino acids from the bloodstream, allowing tryptophan—the amino acid that is a precursor to serotonin—to enter the brain more easily. [14, 16] The result is a quick, albeit temporary, boost in serotonin and an improvement in mood. [4, 5] This biological process is so effective that some researchers describe it as a form of self-medication, as our bodies learn to reach for these foods to feel better. [2, 12]
The Psychology of Comfort
Beyond brain chemistry, powerful psychological factors are at play. The term “comfort food” itself points to an emotional connection. [6] For many, rainy days are associated with childhood memories of staying indoors, feeling safe, and enjoying treats. [3, 17] The smell of baking or the taste of a familiar sweet can trigger a potent sense of nostalgia, activating brain regions linked to memory and emotion. [1, 3] This creates a feeling of security and predictability when the world outside feels gloomy and chaotic. [3, 13] This association is so strong that the comfort we feel is often based on our belief that the food will make us feel better. [7]
Sensory Experience and Warmth
Rainy weather is often accompanied by a drop in temperature. Your body naturally seeks warmth and energy when it's cold. [9, 24] A hot chocolate, a warm slice of pie, or a freshly baked cookie provides not just a chemical mood boost but also literal warmth. This sensory experience—the heat, the rich aroma, the indulgent texture—is deeply satisfying and contributes to the overall feeling of comfort and well-being. [6] These comforting foods activate pleasure and reward centres in the brain, helping to soothe our souls on a dreary day. [6, 13]
