Methodology

How Petcare calculates a recipe.

Engine version 2026.09.29, page generated 2 October 2026. Not yet reviewed by a board certified veterinary nutritionist; we will name the reviewer here when one has. The same facts are available as data at /api/v1/methodology.

What Petcare does, and does not do

Petcare builds everyday recipes for healthy adult dogs from 12 months (18 months at 25 kg or more). It does not build recipes for puppies, pregnant or nursing dogs, dogs with a condition or food allergy a vet has diagnosed, dogs on medication or a special diet, or dogs that need to lose weight. Those dogs are sent to a vet, with a vet packet the owner can print. Petcare makes no claim to treat, cure or prevent anything.

Daily energy

Resting energy requirement (RER) is 70 × body weight in kg to the power 0.75, in kcal a day, the formula used in AAHA and WSAVA nutrition guidance. Daily energy is RER times a factor for the dog's life stage and activity. Every factor is a starting point: individual dogs vary by 20 percent or more, which is why every recipe says to weigh the dog and adjust by 10 percent at a time.

The recipe's energy is held within 3 percent of that calculated target. The 3 percent is a solver tolerance, not a claim about the dog.

The 40 nutrient targets

Each minimum is the higher of the National Research Council's 2006 recommended allowance and the FEDIAF 2025 guideline, expressed per kg of metabolic weight (kg to the power 0.75) and scaled to the dog. Upper limits come from NRC safe upper limits, AAFCO and FEDIAF adult maxima per 1000 kcal, and EU legal maxima for iron and zinc. "By food" means the engine requires food to reach the target; the others are closed by the supplement plan when food falls short.

Ratios: Ca:P between 1 and 2.

Rules the engine adds itself

These are engineering choices, not standards. They are listed so nobody mistakes them for guidance.

• At most 8 foods in a recipe, from 46 everyday foods with full USDA composition.
• Calcium comes from a supplement, dosed to the need and to a calcium to phosphorus ratio of 1.2, inside the 1.0 to 2.0 band that FEDIAF and AAFCO allow. Meat and eggs are rich in phosphorus and poor in calcium, so food alone cannot reach it.
• Iodine is never taken from iodised salt: the salt needed would carry too much sodium.
• Peas are capped at 10 percent of the recipe as a precaution after the FDA's investigation into diets high in pulses and heart disease, which published no threshold.
• Specialty foods (organ meats beyond liver, unusual items) are penalised so the solver prefers ordinary foods when they can do the job.
• For the joints or skin and coat focus, omega 3 (EPA and DHA) is raised to 50 mg per kg of body weight a day from salmon or fish oil, the low end of the range Bauer 2011 reviewed. Petcare makes no treatment claims. Under review: Bauer doses per kg of metabolic weight, and fish oil calls for extra vitamin E.
• Category limits keep the recipe practical: organ meat, fat and fibre are each held inside sensible shares of the day's grams.

Known limits

• The food data is USDA FoodData Central for raw foods. Cooking losses are not modelled; a complete multivitamin covers the vitamins cooking destroys, such as thiamin, and the recipe says so.
• No food in the database carries iodine or chloride values, and few carry vitamin D, so those always come from the supplement plan. A rebuild from USDA with iodine and chloride is planned.
• The supplement plan gives amounts and what to look for on a label. A generic "complete" product may not supply the iodine or vitamin D asked for; show the plan to your vet or pharmacist.
• Growth, pregnancy and lactation equations are not built, which is why those dogs are refused rather than guessed.

Every correction made to the 2022 food data

The engine began from a 2022 spreadsheet. Each problem found in it is logged here, never fixed silently.

1. 19 fatty acid row labels had been turned into clock times by Excel (for example 16:0 stored as 16:00). Labels restored.
2. The sheet's own macro calorie rows use inconsistent conversion factors per food (chicken breast fat is converted at about 4.3 kcal per gram instead of 9). They are ignored: total energy comes from the USDA Energy row and the protein, fat and carbohydrate split is recomputed from grams.
3. Peas moved from fruit to vege: peas are a legume, filed under fruit in the source.
4. Omega 6 and omega 3 values filled from USDA's undifferentiated fatty acid rows for 39 foods whose specific rows were empty, including Apple, Banana, Beef Heart, Beef Kidney, Beef Pancreas, Beef shank.
5. Vitamin D and choline are likely undercounted: the sheet stores vitamin D only as D3 and leaves choline empty for several foods (salmon shows zero for both), so gaps in these two are conservative.
6. Failed the mass balance check and excluded from recipes, because water, protein, fat, carbohydrate and ash should add up to about 100 g per 100 g: Trout (5 g per 100 g); Pumpkin (175 g per 100 g).
7. CBD Oil excluded from recipes: a dosed product with legal restrictions in many countries, stored in the sheet as an ordinary cooking fat.
8. Sweet potato excluded from recipes: its values are not sweet potato but a dry potato gratin mix (USDA FDC 170447), with 2,095 mg of sodium per 100 g, about 38 times real sweet potato.
9. 'Carbo flour' is shown as 'Carob flour'.
10. 'Oats' is shown as 'Oat bran' because its values match USDA oat bran (246 kcal per 100 g).
11. 'Coconut' is shown as 'Coconut (desiccated)'.
12. 'Oyster dried' is shown as 'Oysters' because its values are whole oysters (82 g of water per 100 g), not a dried product.
13. No category for: Cartilage/soft bone, Dandelion root. Excluded from recipes.
14. 33 supplements are listed but only 1 (Bonnie and Clyde Fish Oil (2mL pumps)) has nutrient values, and those are per pump rather than per 100 g. The engine does not use supplements to close gaps; it reports each gap as an exact daily amount.
15. 29 of 46 usable foods have a price. Costs are indicative only, and the currency is not recorded in the source.
16. Salmon: Vitamin A set to 136.0 per 100 g from USDA FDC 173688 (the sheet had 0.0).
17. Chicken breast: Vitamin A set to 9.0 per 100 g from USDA FDC 171077 (the sheet had 0.0).
18. Chicken breast: Choline set to 82.1 per 100 g from USDA FDC 171077 (the sheet had 82.1).
19. Standard 'Taurine' has no values and is skipped.
20. Standard 'Fat' corrected from minimum 1.51, upper 10.8 to minimum 1.81, upper 10.8: the FEDIAF 1.51 sits below the NRC allowance.
21. Standard '20:4 omega 6' has no values and is skipped.
22. Standard 'EPA (omega 3)' dropped: no standard sets a separate EPA minimum; NRC sets EPA and DHA combined.
23. Standard 'DHA (omega 3)' dropped: no standard sets a separate DHA minimum; NRC sets EPA and DHA combined.
24. Standard 'EPA and DHA (omega 3)' corrected from minimum 0.03, upper 0.37 to minimum 0.014, upper 0.37: 0.03 was about twice the NRC allowance with no traceable source.
25. Standard 'Calcium' corrected from minimum 140.0, upper 500.0 to minimum 140.0, upper None, upper 6250.0 per 1000 kcal: 500 was a growth maximum; the adult maximum is 6.25 g per 1000 kcal (AAFCO, FEDIAF).
26. Standard 'Iron' corrected from minimum 1.0, upper 29.0 to minimum 1.0, upper None, upper 170.0 per 1000 kcal: 29 had no NRC basis; engine cap from the EU legal maximum of 68.18 mg per 100 g dry matter at 4,000 kcal per kg.
27. Standard 'Phosphorus' corrected from minimum 110.0, upper 329.4 to minimum 110.0, upper None, upper 4000.0 per 1000 kcal: 329.4 matched no standard; the adult maximum is 4.0 g per 1000 kcal (AAFCO, FEDIAF).
28. Standard 'Zinc' corrected from minimum 2.0, upper None to minimum 2.0, upper None, upper 56.75 per 1000 kcal: engine cap added from the EU legal maximum of 22.7 mg per 100 g dry matter, because oysters carry 45 mg per 100 g.
29. Standard 'Selenium' corrected from minimum 8.25, upper None to minimum 11.8, upper None, upper 500.0 per 1000 kcal: 8.25 was the FEDIAF 2019 minimum, 30 percent under the NRC allowance; upper limit added from the AAFCO adult maximum of 0.5 mg per 1000 kcal.
30. Standard 'Chloride, Cl' has an upper limit of 0, which would forbid it entirely. Upper limit ignored.
31. No food in the database supplies any Chloride, so it can only ever be met with a supplement.
32. Standard 'Iodine' corrected from minimum 29.6, upper 226.46 to minimum 29.6, upper None, upper 2750.0 per 1000 kcal: 226.46 matched no standard; the adult maximum is 2.75 mg per 1000 kcal (AAFCO, EU).
33. No food in the database supplies any Iodine, so it can only ever be met with a supplement.
34. Ratio Ca:P widened from 1.0 to 1.4 to the adult range of 1.0 to 2.0 (FEDIAF 2025, AAFCO).
35. Ratio Zn:Cu removed: 9.5 to 10.5 is the ratio of two NRC allowances, not a standard.
36. Standard 'Thiamin (B1)' corrected from minimum 0.064, upper None to minimum 0.074, upper None: 0.064 was below the NRC allowance.
37. Standard 'Niacin' corrected from minimum 0.45, upper None to minimum 0.56, upper None: the NRC allowance is above the FEDIAF value.
38. Standard 'Pantothenic acid' corrected from minimum 0.39, upper None to minimum 0.49, upper None: the NRC allowance is above the FEDIAF value.
39. Standard 'Vitamin B6' corrected from minimum 0.04, upper None to minimum 0.049, upper None: the NRC allowance is above the FEDIAF value.
40. Standard 'Vitamin D3' corrected from minimum 0.45, upper None to minimum 0.45, upper 2.62: NRC sets a safe upper limit; the 2022 table had none.
41. Standard 'Vitamin K' dropped: the NRC value is for menadione while the food data holds phylloquinone, FEDIAF says dog food needs no added vitamin K, and the 2022 upper of 2.60 was the vitamin D limit in the wrong row.
42. 9 recommended items in the recipe sheet are not foods in the database (several are nutrients or supplements): Antioxidant, Any meat( muscles), Digestive enzymes, Fennel seeds, Folic acid, Green beans, Parsley leaf, Phosphorus, Riboflavin.
43. Avoid rules naming foods not in the database, shown to owners as advice instead: Asparagus, Avocado, Fatty proteins, Grapes, Hard bones, Pork, Saturated fats.
44. Joints and mobility: the 2022 rules are replaced by the evidence review. Only omega 3 sources (Fish oil, Salmon) are preferred, and the avoid rules for Barley, Brown rice flour, Oat bran are removed as unsupported.
45. Skin and coat: the 2022 rules are replaced by the evidence review. Only omega 3 sources (Fish oil, Salmon) are preferred, and the avoid rules for Beef Heart, Beef Kidney, Bonnie and Clyde Fish Oil (2mL pumps), Fish oil, Lamb Heart, Lamb Kidney, Lamb Liver, Lamb shank, Salmon, Trout are removed as unsupported.
46. CONTRADICTION for Pancreas: the recipe sheet both recommends and forbids Sweet potato. The avoid rule wins until a veterinary nutritionist decides.
47. 24 breeds loaded from the breeds sheet.
48. Breed conditions outside the ten concerns, kept as notes only: Breathing issues, Epilepsy, Hypothoiroidism, Hypothyroidism, Respiratory problems, Tracheal collapse, Tumors.
49. Breed recipe items not in the database: Fresh water fish, Green beans, Greenbeans, Olive oil, Rapeseed oil, Salmon oil, Turkey, Turkey liver, coconut oil.

Tests

More than 220 automated tests run on every change: energy within 3 percent of target, upper limits respected, left out ingredients removed, iodine never from salt, calcium dosed to the ratio, the healthy adult scope enforced on the server, and no recipe ever passed off as veterinary advice.

Petcare is software, not veterinary advice. The research behind these choices is kept in the project's research files and summarised in the articles.