My kitten is too skinny — what should I do? First, check whether it really is too skinny, and then see a vet. A kitten that is too thin may not be getting enough food, or it may be unwell — parasites, infections, and other problems can all slow growth, and they need a vet to find them. This guide covers how to tell if a kitten is too thin, the common causes, what to feed, and when a thin kitten is an emergency. A kitten that is not gaining weight needs a vet, not just more food.
The short version is: feel the ribs — you should feel them easily under a thin layer of fat, not see them sharply — weigh the kitten every two weeks, and see a vet promptly if it is not gaining weight, if it is losing weight, if it is lethargic or off its food, or if it has vomiting or diarrhoea. A kitten that is too thin and is eating well needs a vet check, not just more food. The kitten weight chart by age guide gives the rough growth shares by age, and the how much food should a kitten eat guide gives the calorie tables.
How to tell if a kitten is too skinny
Feel the ribs with flat fingers and light pressure, while the kitten is standing. You should feel each rib easily under a thin layer of fat — like feeling the bones in the back of your hand. If the ribs are sharp under your fingers, and easy to see as well as to feel, the kitten is too thin. Look down from above: you should see a waist, but not a very sharp one, and the hips should not stick out. Look from the side: you should see a tummy tuck, but not a very deep one. A kitten that is too thin has ribs that are easy to see, a waist that is very obvious, and hips that stick out.
Weigh the kitten every two weeks, at the same time of day, on the same scales, and write the number down — the line over weeks is what matters, not any single reading. Compare with the breed's expected adult weight: as a very rough guide, a kitten's weight as a share of its expected adult weight is about a fifth to a quarter at 8 weeks, about half to two-thirds at 6 months, and about four-fifths or more at 12 months. A kitten that is well below the rough share for its age, or that is not gaining weight over two weeks, needs a vet check. The kitten weight predictor estimates adult weight from the kitten's current weight and age.
Why is my kitten too skinny?
A kitten can be too thin because it is not getting enough food: a kitten growing fast needs a lot of calories, and a kitten that is fed adult amounts, or fed by eye rather than by measure, can be underfed without anyone noticing. A kitten in a litter with bigger, pushier littermates can be pushed away from the bowl, or from the mother, and get less than it needs. A kitten that has recently changed homes, or that is stressed by a move, may eat less for a while. Those causes are fixed by more food, fed little and often, and a calm routine — and by feeding the kitten separately if it is being pushed away from the bowl.
But a kitten that is too thin and is eating well needs a vet check, because parasites, infections, and other problems can all slow growth. Parasites are a common cause of slow growth in young animals and are easy to treat — your vet can check a stool sample and treat them. Infections, dental problems, and some other conditions can also slow growth, and they need a vet to find them. A kitten that is too thin and is off its food, lethargic, or has vomiting or diarrhoea should be seen by a vet the same day, because young animals dehydrate fast. The how much food should a kitten eat per day by weight guide gives the calorie tables by weight.
What to feed a kitten that is too skinny
Feed a complete and balanced kitten food, measured with scales or a measuring cup, split into three or four meals a day — a young animal's stomach is small, so it cannot eat enough in one or two meals to meet its needs. A kitten over four months old needs about 2.0 times its resting energy requirement (RER), and a puppy under four months needs about 3.0 times RER (about 2.5 for kittens), where RER equals 70 times body weight in kg to the power of 0.75. Use the calorie table for the kitten's weight, not the adult table, and re-check every two weeks as the kitten grows.
Do not add fatty scraps, gravy, or oil to the food: fat upsets the stomach, and a kitten with an upset stomach eats less, not more. Do not feed adult food to a kitten: adult food does not have enough calories or nutrients for growth, and a kitten fed adult food will grow more slowly than it should. Do not feed a lot more all at once: add about 10% at a time, wait two weeks, and then decide. Feed in a quiet place, at the same times every day, and if there are other pets in the house, feed the kitten separately. The how often should you feed a kitten guide gives the feeding schedule, and the kitten feeding schedule by age guide gives the schedule from weaning to adulthood.
When a thin kitten is an emergency
See a vet the same day if the kitten is lethargic, will not eat or drink, has vomiting or diarrhoea, is cold to the touch, or is losing weight. Young animals dehydrate fast, and a kitten that is not eating or drinking can become seriously ill within a day. Bring a note of what the kitten has eaten, how much, and any vomiting or diarrhoea — that information helps the vet far more than a guess about the food. Do not try to treat a sick kitten at home with medicines meant for people, and do not fast a kitten without veterinary advice.
At the vet, expect a weigh-in, a check of the kitten's body condition, and questions about food, feeding times, and other pets in the house — and possibly a stool sample, because parasites are a common cause of slow growth in young animals and are easy to treat. The vet may also check for infections and other problems. Do not be embarrassed to ask: a kitten that is too thin is a common worry, and a vet would rather check a kitten that turns out to be fine than miss one that is ill. The vaccination schedule helper and the deworming schedule helper cover the routine care that keeps a kitten growing well.
Mistakes to avoid
The most common mistake is feeding more without checking why the kitten is thin: a kitten that is thin because of parasites or illness needs a vet, not just more food, and more food without treating the cause will not fix the growth. The second is feeding adult food to a kitten: adult food does not have enough calories or nutrients for growth. The third is feeding a lot more all at once: a kitten that is suddenly given much more food can get an upset stomach, and a kitten with an upset stomach eats less, not more. The fourth is comparing kittens of different breeds or sizes: a large-breed puppy at 6 months weighs far more than a small-breed puppy of the same age, and both are normal for their size.
The fifth is weighing too rarely: a kitten grows fast, and a kitten weighed once a month is being weighed too rarely — weigh every two weeks. The sixth is judging by a single reading: a kitten that is a little below the chart on one day is usually fine, and the line over weeks is what matters. The kitten growth chart by breed size guide gives the growth tables by size, and the when is a cat fully grown guide gives the growth ages by size and breed.
For related reading, see the kitten weight chart by age guide, the how much food should a kitten eat guide, the kitten weight predictor, the how often should you feed a kitten guide, the vaccination schedule helper, the deworming schedule helper.
Frequently asked questions
How do I know if my kitten is too skinny?
Feel the ribs — you should feel them easily under a thin layer of fat, not see them sharply. Look for a waist from above and a tummy tuck from the side. A kitten that is too thin has ribs that are easy to see, a waist that is very obvious, and hips that stick out. Weigh every two weeks and compare with the breed's expected adult weight.
Why is my kitten too skinny?
It may not be getting enough food, it may be pushed away from the bowl by bigger littermates, or it may be unwell — parasites, infections, and other problems can all slow growth. A kitten that is too thin and is eating well needs a vet check, not just more food.
What should I feed a kitten that is too skinny?
A complete and balanced kitten food, measured with scales, split into three or four meals a day. A kitten over four months old needs about 2.0 times its resting energy requirement, and a puppy under four months needs about 3.0 times (about 2.5 for kittens). Add about 10% at a time, and re-check every two weeks.
Can I feed my kitten adult food?
No — adult food does not have enough calories or nutrients for growth, and a kitten fed adult food will grow more slowly than it should. Feed a food labelled complete and balanced for kittens until your vet says the kitten is ready for adult food.
When should a thin kitten see a vet?
Promptly if it is not gaining weight over two weeks, or if it is losing weight — and the same day if it is lethargic, will not eat or drink, has vomiting or diarrhoea, or is cold to the touch. Young animals dehydrate fast, and a kitten that is not eating or drinking can become seriously ill within a day.
How often should I weigh my kitten?
Every two weeks, at the same time of day, on the same scales, and write the number down. A kitten grows fast, and the amount of food changes quickly, so a kitten weighed once a month is being weighed too rarely.
Results on this page are estimates for general information only and are not veterinary advice. If your pet is ill, underweight, overweight, pregnant, or has a health condition, consult your veterinarian before changing diet or care.