Health
Ribs on show, hips sticking out, a harness that hangs off him. A dog who is lean by build is one thing; a dog who is losing weight now is quite another.
Caution. Visible weight loss over a few weeks, a dog eating a lot and still losing weight, heavy thirst, diarrhoea or vomiting for several days, pale gums: see the vet within a day or two. A very thin rescue dog must not be fed freely from day one.
Do not look for the answer in a Facebook group, on TikTok or on a forum. Look for someone trained for this: your dog's own veterinarian, the only person who can examine, investigate and treat them.
Use this page to know what to observe, what to note and what to ask at the appointment, not to treat at home. If you still have doubts after a consultation, ask another vet or a specialist (dermatologist, internist) for a second opinion, not a group. And if you do not have a regular vet yet, find one now, while your dog is healthy: how to choose a veterinary clinic.
You put on last year's harness and it hangs off him. Your dog, who has always been the right weight, has dropped three kilos since the start of summer and you have only just noticed. Or everyone at the park keeps telling you he is thin: you can see his ribs when he stretches and his hips stick out, even though he gets the amount on the bag and a bit more. Or you have taken on a rescue who is skin and bone and you want to get him back on his feet as quickly as possible. Below is how to tell whether he really is too thin, why a dog who eats can still lose weight, what the vet checks and how to help him put weight on without upsetting his stomach.
A dog who has always been lean and is otherwise full of beans is not an emergency. New weight loss, especially fast weight loss, is. Ring the vet the same day or the next if:
That last one needs spelling out. A dog who has been starved for a long time must not be given free access to food from day one. His body is no longer used to food, and a big meal can throw the salts in his blood badly out of balance, with serious consequences. How much he gets and how fast portions go up is the vet's call.
The scales. Once a week, same scales, same time of day. A small dog fits on kitchen scales, or you weigh yourself holding him and then without him. If he has lost more than 10% of his weight without being on a diet, book an appointment.
Body condition score. Vets use a scale from 1 to 9, where 4–5 is ideal. At home you check it with your hands:
| What you feel and see | What it means |
|---|---|
| Ribs, spine and pelvic bones visible from a distance, muscle wasted away | Very thin (1–2 out of 9): see the vet |
| Ribs easy to see, the tops of the vertebrae felt straight away, a very deep waist | Thin (3 out of 9) |
| Ribs easy to feel under a thin layer of fat but not visible; a waist seen from above, a tucked-up tummy from the side | Ideal (4–5 out of 9) |
| Ribs hard to feel, waist barely visible | Overweight |
Take photos from above and from the side once a month, in the same position. Your eye gets used to a dog you see every day. Photos stay the same.
Exactly what he eats. The grams of food, weighed (a cup is not a measurement), the treats, everything the rest of the household slips him. A lot of dogs who are "thin even though they eat loads" are in fact eating less than their owner thinks, or eating a food that does not cover the energy they burn.
His poo. How much, what colour, what consistency. Very bulky, pale, greasy poo that leaves a smear, in a dog who wolfs his food, can mean the food is not being digested. German Shepherds have a known tendency to a disease of the pancreas that looks exactly like that.
The rest of his day. How much he drinks, how much he wees, how much exercise he gets, and whether anything has changed: another dog in the house eating from his bowl, more sport, a winter spent outdoors.
Breed. Greyhounds, whippets and some hunting and working dogs are lean by build. You can see their last ribs and hip bones, and for them that is normal. If you are not sure where yours fits, your vet will tell you.
A simple rule of thumb for very thin rescue dogs: in the first month you are watching his gut, not his weight. Firm poo, a bright dog and a good appetite mean you are on the right track, even if the scales have barely moved. The kilos come once his gut has got used to food again.
Older dogs are a different story. After ten or twelve years, many lose muscle over the back and thighs while the scales show the same number. More food will not fix that. Good-quality protein and gentle daily exercise help, and a vet check is worth having, because sore joints also make them move less.
Sporting and working dogs are a case of their own. A dog who does mantrailing three times a week, runs in the mountains or pulls a sled in winter may need far more food than the bag suggests. If he loses weight during the training season, check first that he is getting enough. If two or three weeks of bigger portions still put nothing on, see your vet.
What dog owners search for most often on the internet about this problem, with the short answer. The answers are a guide only: the decision belongs to your dog's own vet, after an examination.
Put your hands on his ribs. At an ideal weight you can feel them easily under a thin layer of fat, but you cannot see them. If you can see them from a distance, along with the tops of the vertebrae and the hip bones, he is too thin. Greyhounds and some working dogs are lean by build; if you are not sure where yours fits, ask your vet.
Sometimes he is simply eating less than he needs for the energy he burns. Other times it is illness: worms, Giardia, a pancreas not making enough enzymes, diabetes, or gut or thyroid problems. Weigh his food for a few days, note what his poo looks like and take him to the vet.
Gradually. Raise his portion by about 10% a week, split the food into three or four meals, pick a more energy-dense food and switch over across five to seven days. Feed him in peace, away from other dogs. Steer clear of fatty table scraps, which can inflame the pancreas.
Slowly, with small, frequent meals, following your vet's plan. A dog starved for a long time who suddenly gets a lot of food can have a serious reaction, with the salts in his blood thrown out of balance. He reaches a good weight over months, and weighing him weekly shows you whether it is working.
The information on this page is educational and does not replace an examination. For full details and a diagnosis, consult your dog's own veterinarian.
They often come together: the same causes, plans that complement each other.
He sniffed the bowl and walked off, twice running, yet he's drinking and wagging. With a bright adult you can wait a day. With a puppy or an old dog, you can't.
A pot-bellied puppy, rice-like segments by the tail, soft stools for no clear reason. Intestinal worms are common, easy to treat and kept at bay with a schedule.
The water bowl is empty by lunchtime, she wakes you at night to go out and loses weight though she eats everything. Diabetes is for life, but very manageable.
A bag of kibble and a sheet saying three times a day. Feeding looks simple, which is exactly why it is where most of the unnoticed mistakes happen.
We work with your dog's behaviour, not its health. For any sign described here, book an appointment with your own vet; the related services page explains how to choose a clinic.