Hill's Prescription Diet j/d Reduced Calorie Dry Dog Food review

Ingredients, as declared: Cereals, vegetable protein extracts, derivatives of vegetable origin, meat and animal derivatives (chicken 5%), seeds, oils and fats, minerals, molluscs and crustaceans.

The list gives categories, not named items. Cereals come first, then vegetable protein extracts and derivatives of vegetable origin, and only then meat and animal derivatives, with chicken printed at 5%. Chicken is the one species the label commits to anywhere, so whatever else sits inside that meat entry is not identified.

Molluscs and crustaceans close the recipe. Crustacean shells are the usual commercial route to glucosamine, and finding them at the tail of a joint food follows that pattern, although no percentage is printed beside them. A household that keeps shellfish away from the dog will want to have spotted that entry.

This label takes you only so far if you need to know exactly what your dog reacts to. Cereals can mean any grain, derivatives of vegetable origin covers a wide field of plant processing, and the meat heading names chicken and stops there. That is the honest reading of a category-style declaration and it is worth putting in front of the vet before the food is asked to exclude anything.

Crude fibre is declared at 9.1% and converts to 9.9% of dry matter, which is the figure the whole recipe turns on. Fibre at that level dilutes the energy in every mouthful, which is precisely what a reduced calorie design sets out to do rather than something the food is short of. Energy lands at 341 kcal per 100g, with protein at 23.4% of dry matter, fat at 13.9% and the carbohydrate estimate at 47.8%.

The added trace elements are printed dose by dose: iron at 75.9mg, zinc at 133mg, copper at 7.5mg, manganese at 7.8mg, iodine at 1.9mg and selenium at 0.2mg, with a natural antioxidant closing the panel.

The bag's own guide opens at 30 grams a day for a 1kg dog and reaches 545 grams at 50kg, with 165 grams listed at 10kg. On a therapeutic diet the amount fed and how long it is fed for are set by the practice that prescribed it. Whether the food suits your own dog is theirs to answer as well.

It comes in a 12 kg bag, at £5.53 a kilo. Fed to the label's guide, a 15kg dog takes about 246 grams a day, which works out at £1.36 a day on that per kilo figure.