How a swap actually works.

Before substituting anything, Eatvia classifies each ingredient by the role it plays: structure (flour, eggs), fat and mouthfeel (butter, cream, nuts), binding and emulsifying (egg, mustard, starch), acid and balance (vinegar, citrus), leavening, umami depth, and aroma. A swap is only accepted if it covers the same role. That is why egg in a cake is replaced differently (aquafaba or a flax gel, for lift and binding) than egg in a glaze (plant milk with a little maple, purely for colour).

Allergy handling is group-based rather than word-based. If you flag tree nuts, Eatvia excludes the whole group plus common derivatives — nut butters, nut milks, marzipan, praline, nut oils, pesto — instead of only the exact word in your profile. It also respects known cross-reactive relationships (for example birch-pollen-related raw fruit sensitivities, or shellfish and molluscs being flagged together) and treats ambiguous compound ingredients such as "natural flavouring" or "may contain" products as unsafe by default.

Gluten, dairy, soy, egg, sesame, fish, shellfish and peanuts each carry their own hidden-source list — soy sauce in a marinade, whey in a stock powder, tahini in a dressing — so the swap covers the ingredient you would actually have missed on the label.

Baking is chemistry, so quantities are recalculated rather than copied. Gluten-free flour blends get extra hydration and a binder; sugar reductions are compensated where sugar was providing moisture and browning; fat swaps account for the water content of the replacement (butter is roughly 16% water, oil is none). Cooking times and temperatures are nudged when the swap changes how quickly a dish sets or browns.

Where two substitutions are equally good, Eatvia prefers the one already in your pantry and, among those, the item closest to its use-by date. Recipes with high pantry coverage surface first, and shopping lists exclude what you have. Household food waste is dominated by ingredients bought for one recipe and never used again — ranking swaps by what you own attacks exactly that.

Every substitution ships with three things: why it is safe for your profile, what it changes about taste or texture, and how confident Eatvia is. When confidence is low, the swap is labelled rather than quietly shipped.

Eatvia is a cooking assistant, not a medical device. It cannot read the label on the jar in your cupboard, and manufacturers change formulations. For severe or anaphylactic allergies, always verify packaging yourself and follow the advice of your clinician. Questions about a specific adaptation? Ask us.