If you’ve noticed that the person you support has developed a sudden enthusiasm for biscuits, cake, or anything sweet — when they weren’t particularly interested in sugary food before — you’re not imagining it. A shift towards sweet foods is a recognised and fairly common experience in dementia, and it has real neurological roots.
Understanding why it happens can make it easier to respond with both care and common sense, rather than feeling like every mealtime is a negotiation.
Why does the brain drive sweet cravings?
The brain runs almost entirely on glucose — it uses more energy than any other organ in the body, despite being only around 2% of our body weight. In dementia, particularly Alzheimer’s disease, the brain’s ability to metabolise glucose efficiently becomes impaired. Some areas of the brain are simply not extracting energy from food the way they used to.
One response to this energy deficit is for the brain to signal a craving for quick, easily accessible glucose — which sweet foods provide almost immediately. It’s not a conscious decision; it’s the brain trying to meet its own energy needs as best it can with a changed metabolism.
There are other factors at play too. As dementia progresses, changes in the frontal lobes can reduce impulse control and shift the brain’s reward responses, making sweet flavours feel more immediately pleasurable. Taste and smell perception also tend to change — bitter and savoury flavours become harder to detect, while sweetness remains more reliably enjoyable. Food that once tasted complex may now taste bland, and sweeter options feel more satisfying.
There’s an emotional dimension as well. Sweet foods are often deeply embedded in comfort and memory — a particular biscuit, a favourite pudding, the smell of a cake baking. For someone whose access to recent memories is reducing, these older emotional associations can feel particularly strong and grounding.
Does that mean sweet food is helpful?
Not quite — though it’s not as simple as just saying no to sugar either. A diet very high in refined sugar can contribute to blood sugar spikes and crashes that may worsen confusion or mood, and over time it can crowd out the more nutritious foods the brain needs. There’s also an established link between insulin resistance and Alzheimer’s disease, which makes excessive sugar intake worth taking seriously as a long-term pattern.
But there’s a real-world dimension here too. If the person you support is distressed, under-eating, or resistant to food, and a biscuit with their tea brings them comfort and gets something into them — that matters. Rigid restriction isn’t the answer, and forcing dietary rules on someone who no longer has the context to understand them will usually cause more harm than a biscuit would.
What tends to help
Offering naturally sweet alternatives — fruit, yogurt, a small portion of something genuinely enjoyed — can satisfy the craving while providing better nutrition. If sweet foods are going to be part of a meal or snack, pairing them with protein (a small handful of nuts, some cheese, a boiled egg) slows glucose absorption and reduces the spike-and-crash effect.
Keeping meals and snacks regular and predictable is worth more than any individual food choice. Hunger and low blood sugar both worsen confusion and can amplify cravings, so not letting the person go too long between eating and drinking matters.
It’s also worth keeping hydration in mind. Thirst and hunger signals can become confused in dementia, and what presents as a craving for sweet food is sometimes actually a need for fluids.
A simple food and drink diary — noting what was eaten, when, and how the person seemed afterwards in terms of mood and alertness — can help identify patterns that are worth discussing with the GP or dietitian if you have concerns.
Further reading
Alzheimer’s Society — Eating and drinking NHS — Dementia and nutrition British Nutrition Foundation
Understanding how dementia affects the brain — including changes in appetite, taste, and energy use — is part of what we explore in the Getting to Know Dementia programme. Find out more about the programme and upcoming dates.