Kitten, adult, senior & pregnancy
Requirements are not constant across a cat's life, and two moments matter more than any other: the growth phase, and the day the cat is neutered. Getting those two right prevents most of the diet-related problems a cat will ever have.
1. The life stages
AAFCO recognises only three nutritional life stages: growth and reproduction, adult maintenance, and all life stages (which simply means the food meets the growth profile). There is no AAFCO “senior” category; senior foods are formulated to the adult maintenance profile with marketing attached.
Clinically, though, the 2021 AAFP–AAHA feline life stage guidelines use a more useful five-stage framework, because what changes with age is monitoring and disease risk more than the nutrient profile.
| Stage | Age | Nutritional priority |
|---|---|---|
| Kitten | birth – 1 year | Growth profile; energy-dense, high protein, DHA, calcium and phosphorus in a controlled ratio |
| Young adult | 1 – 6 years | Adult maintenance; the critical period for preventing obesity, which usually starts within a year of neutering |
| Mature adult | 7 – 10 years | Maintenance, but start watching weight, muscle mass, and phosphorus intake |
| Senior | 10 – 14 years | Highly digestible protein, adequate calories, monitoring for CKD, hyperthyroidism and diabetes |
| Geriatric | 15+ years | Maintaining intake and body weight becomes the priority; energy needs rise again |
2. Kittens: birth to twelve months
Nought to four weeks - milk only
Queen's milk, or if orphaned, a proper kitten milk replacer. Never cow's milk: it is too low in protein and fat for a kitten and its lactose causes osmotic diarrhoea. Orphaned kittens need feeding every two to three hours around the clock at first, kept warm, a chilled neonatal kitten cannot digest: and stimulated to toilet after each feed. This is a job to do with veterinary guidance.
Four to eight weeks - weaning
Introduce wet kitten food mixed with kitten milk replacer to a gruel, thickening it over two to three weeks. Most kittens are fully weaned by seven to eight weeks. Weaning is also the window in which food preferences form, so expose kittens to several textures and protein sources now: it costs nothing and may save you enormous difficulty when the cat is twelve and needs a therapeutic diet.
Two to six months - the fast growth phase
| Nutrient | Kitten (growth) minimum | Adult minimum | Why |
|---|---|---|---|
| Crude protein | 30 % | 26 % | Rapid tissue accretion; good kitten diets run 40–50 % |
| Calcium | 1.0 % | 0.6 % | Skeletal growth |
| Phosphorus | 0.8 % | 0.5 % | Must stay in a Ca:P ratio of roughly 1.1:1 to 1.5:1 |
| Arginine | 1.25 % | 1.04 % | Urea cycle capacity under high protein turnover |
| Lysine | 1.20 % | 0.83 % | Growth-limiting amino acid |
| Tryptophan | 0.25 % | 0.16 % | Growth and neurotransmitter synthesis |
| Vitamin A | 9,000 IU/kg | 5,000 IU/kg | Growth and immune function |
| Vitamin D | 750 IU/kg | 500 IU/kg | Calcium handling and bone mineralisation |
| DHA | not on the AAFCO list | , | Strong evidence for neural and retinal development; look for it in the ingredients |
Energy. A kitten needs roughly 200–250 kcal per kilogram of body weight per day at two to four months: two and a half times an adult's rate per kilo. Feed four small meals a day to twelve weeks, then three, then two by around six months. Kittens under six months should generally have food available fairly freely; they have small stomachs and enormous requirements.
Food. Use a food labelled for growth or all life stages until twelve months. Large breeds (Maine Coon, Ragdoll, Norwegian Forest) grow until eighteen months to two years and should stay on kitten food correspondingly longer.
Common mistake
Feeding adult maintenance food to a kitten. It does not meet the growth profile for protein, calcium, phosphorus, or several amino acids and vitamins, and the consequences, skeletal abnormalities, poor growth, are not always reversible. Check the AAFCO statement says growth or all life stages.
Danger
Do not supplement a complete kitten diet with calcium. Adding calcium to a balanced food distorts the calcium-to-phosphorus ratio and can cause skeletal disease in a growing kitten. The most common route to this is a well-meaning owner adding a supplement, or feeding an all-meat home-made diet that is calcium-deficient and then over-correcting.
3. The neutering cliff
The most predictable weight gain in a cat's life happens in the six to twelve months after neutering, usually between six months and two years of age. Removing the gonads reduces resting energy expenditure by roughly 20–30 % and simultaneously increases food intake. Studies consistently show free-fed cats gain substantial weight in the months following the procedure.
The fix is straightforward and almost nobody does it: recalculate the portion at the time of neutering, cutting to about 75–80 % of the previous intake, and move from free-feeding to measured meals. Weigh monthly for the next year. Preventing this weight gain is far easier than reversing it, and it is probably the single highest-leverage intervention in a young cat's life.
4. Adult maintenance: one to seven years
The steady state, and the stage where the main risk is complacency. A neutered indoor adult needs
roughly RER × 1.0–1.2 (see how much to feed for)
the numbers. The nutritional targets are those on the
daily requirements page.
What matters at this stage is monitoring rather than formulation:
- Weigh monthly and record it. A trend is visible in the numbers long before it is visible in the cat.
- Body condition score every few months.
- Keep dietary moisture high: this is the stage where urinary disease commonly first appears, particularly in neutered male cats.
- Annual veterinary examination, moving to twice yearly from about seven.
5. Pregnancy and lactation
The most nutritionally demanding period in a cat's life, and the one people most often get wrong by waiting too long to increase intake.
- Switch to a growth or all-life-stages food at breeding, not at birth. The gestation and lactation requirements match the growth profile.
- Cats gain weight steadily from early gestation, unlike dogs, storing reserves for
lactation. Expect roughly a 40 % increase in body weight by term. Energy intake rises from about
RER × 1.6early to× 2.0at term. - Lactation is the peak. Requirements reach
RER × 2.0to× 6.0depending on litter size, a queen with six kittens at three to four weeks of lactation may need four to six times maintenance. Feed free choice throughout; it is very difficult to overfeed a lactating queen. - Taurine matters especially here. Deficiency in the queen causes fetal resorption, low birth weight, poor kitten survival, and developmental abnormalities.
- DHA in the maternal diet supports neural and retinal development in the kittens.
- Water intake rises sharply during lactation. Make it easy.
6. Senior and geriatric: ten years and up
The received wisdom that old cats need less protein is wrong, and it has probably harmed a great many cats. It was imported from human and canine nutrition and does not survive contact with the feline data.
What actually changes
- Digestive efficiency falls. Roughly a fifth of geriatric cats show reduced ability to digest protein, and about a third show a significant reduction in fat digestion. So the same food delivers fewer usable nutrients.
- Energy needs rise again after about eleven or twelve. Unusually among species, older cats need more calories per kilogram, not fewer, partly from that reduced digestibility. Many geriatric cats are underweight, not overweight.
- Lean muscle is lost (sarcopenia). Cats lose muscle mass progressively from about eleven, and loss of lean body mass is associated with shorter survival.
- Senses dull. Reduced smell and taste depress appetite; warming food helps.
- Disease prevalence climbs steeply: chronic kidney disease, hyperthyroidism, diabetes, dental disease, osteoarthritis.
Rule of thumb
Older cats need more highly digestible protein, not less, figures around 5–6 g of protein per kilogram of body weight per day are cited for maintaining lean mass, against roughly 4 g for a young adult. Restricting protein in a healthy senior cat accelerates muscle loss. Protein restriction is appropriate only in specific diagnosed disease, chiefly advanced chronic kidney disease, and then under veterinary direction.
Practical senior feeding
- High-quality, highly digestible animal protein, not less protein.
- Wet food, warmed, in several small meals, supports hydration, appetite, and easier eating with dental disease.
- Watch phosphorus, because chronic kidney disease is extremely common in this age group. Once CKD is diagnosed, phosphorus restriction is the best-evidenced dietary intervention there is.
- Omega-3 fatty acids (EPA and DHA) for joint comfort and renal support.
- Raise the bowls slightly and put food and water where an arthritic cat does not have to jump. Osteoarthritis is present radiographically in the large majority of cats over twelve and is under-diagnosed because cats do not limp, they simply stop jumping.
- Weigh monthly without fail, and see the vet twice a year with bloodwork including thyroid and renal panels. Weight loss in an older cat is never “just age”.
Common mistake
Assuming weight loss in an old cat is normal ageing. It is the presenting sign of hyperthyroidism, chronic kidney disease, diabetes, intestinal disease, and cancer; all of which are common in this age group and several of which are very treatable if caught early. An old cat losing weight needs bloodwork, not a bigger bowl.
Sources
- AAFP and AAHA: Feline Life Stage Guidelines (2021). catvets.com
- Association of American Feed Control Officials, Cat Food Nutrient Profiles, growth and reproduction column.
- Canadian Veterinary Medical Association: Meeting the Nutritional Needs of Senior Cats (2023). canadianveterinarians.net
- Perez-Camargo G., “Cat nutrition: what is new in the old?” Compendium on Continuing Education (2004), on geriatric digestibility and energy needs.
- National Research Council: Nutrient Requirements of Dogs and Cats (2006), gestation and lactation chapters.
- Merck Veterinary Manual: nutrition of growing and reproducing cats.