Human foods pets can eat, and how to share them safely

The reputation of table scraps is worse than it deserves and more dangerous than it sounds, both at once.

A good deal of ordinary food is perfectly fine for a dog or cat in small, plain amounts; a short list of common foods is toxic and belongs nowhere near them. Knowing which is which, and holding to one rule about quantity, is all it takes to share safely.

The ten per cent rule comes first

Whatever you share is a treat, and treats should stay under about a tenth of the day's calories.

The other nine tenths is a complete, balanced diet, because that's where the vitamins and minerals an animal actually needs are measured out. Share past that and you aren't topping up a diet, you're replacing it with something that was never formulated to be one. The treat budget matters more than the specific food.

Cats change the picture, too. A cat is an obligate carnivore — it runs on meat and takes little interest in the fruit and vegetables a dog will happily eat. For a cat, a scrap of plain cooked meat or fish is the treat that makes sense; a green bean isn't harmful, just pointless.

Foods that are usually fine, plain and in moderation

Plain cooked lean meat — chicken, turkey, beef — with no bones, skin or seasoning, is the safest thing to share with either species.

So is a little cooked egg, and cooked boneless fish such as salmon. For dogs, most plain vegetables are welcome: carrot, green beans, peas, plain cooked pumpkin or sweet potato. Plain cooked rice or oatmeal sits well on an upset stomach.

Fruit is a dog thing more than a cat thing, and a few are good: apple without the core or pips, banana, blueberries, seedless watermelon flesh. Small amounts — fruit is sugar, and sugar is calories. None of this is a meal; all of it is a topping on a diet that already does the real work.

A few of these earn their place beyond being harmless. Carrot and green beans are close to calorie-free, which makes them the obvious treat for a dog on a diet that still expects something. A spoon of plain pumpkin is genuinely useful for a mildly loose or constipated stomach. And plain cooked chicken is the highest-value training reward most dogs will ever meet, which means a very small piece buys a great deal of attention.

Plain is the whole trick

Almost everything that turns a safe food dangerous is what we add to it.

Onion and garlic are toxic and hide in gravy, stuffing and seasoning. Salt, butter and rich sauces upset stomachs and pile on calories. A cooked bone can splinter, and fried food invites the kind of pancreas flare-up that ends at the vet. The rule is simpler than a list: share the food before it reaches the pan and the seasoning, not the version off your plate.

Take the packaged versions seriously too. Tinned fish in brine is salty and in oil is fatty; in spring water it's fine. Peanut butter is fine unless it contains xylitol, which some brands now use and which is dangerous to dogs — so the jar has to be read rather than assumed. Stock cubes, gravy granules and most ready-made sauces are built on onion and salt. And anything labelled sugar-free is worth checking for the same reason as the peanut butter.

Foods that aren't toxic but cause trouble anyway

A middle category gets less attention than it should, because nothing on it will poison an animal and all of it lands pets at the vet.

Fatty trimmings, skin, sausages and anything fried can set off pancreatitis, which is painful, sometimes serious, and disproportionately common after Christmas and barbecue season. Corn cobs and large fruit stones cause obstructions and routinely need surgery. Cooked bones splinter; raw ones are debated and still break teeth. A sudden large quantity of anything rich produces a night of diarrhoea in an animal used to one steady food.

Dairy sits here too. Many adult dogs and cats are lactose-sensitive, so a lick of plain yoghurt or a small piece of hard cheese suits some animals and loosens others — and cheese in particular is far more calorific than the size of the piece suggests, which makes it a poor daily habit even for the dogs that tolerate it.

None of this is a reason to panic over a dropped chip. It's a reason to treat the rich end of the table as the part you don't share, rather than assuming that anything short of the toxic list is fine.

The foods to never share

A handful of common foods are toxic even in small amounts, and no quantity is a safe treat: chocolate, grapes and raisins, onion, garlic and chives, xylitol (the sweetener in sugar-free gum and many baked goods), macadamia nuts, alcohol, caffeine, and raw bread dough.

Grapes and xylitol in particular do serious harm fast. The full list, with what each one does and what to do if it's eaten, is on the toxic-foods page — worth reading once so the dangerous ones are already familiar.

How to share without creating a beggar

There's a behavioural cost to sharing that has nothing to do with nutrition, and it's the reason so many households end up with a dog at the table.

Food handed over from a plate, during a meal, in response to attention, teaches exactly the lesson it looks like: staring works. Food put in the animal's own bowl afterwards, or used as a training reward in a different room at a different time, teaches nothing of the sort — and it's the same piece of chicken either way.

So make it a rule the whole household holds, because one person who gives in trains the animal for everyone. Nothing comes off the table while people are at it. Scraps worth saving go in the bowl at the next meal. Guests are told, kindly and in advance, because they'll otherwise be delighted to help.

The same applies to counters and worktops. A dog that finds food up there once will check for the rest of its life, and a cat that's fed from the worktop has been given permission to be on it. That isn't about the food's safety; it's about not building a habit you'll spend years undoing.

How to introduce anything new

Add one new food at a time, in a small amount, and watch the next day's stools and appetite before offering more — that way a food that doesn't agree is obvious rather than a mystery mixed in with three others.

Dairy is the classic surprise: many adult dogs and cats are lactose-sensitive, so a lick of plain yoghurt suits some and loosens others. Anything richer than usual, given in quantity, upsets a stomach that's used to one steady food, which is also why changing the main diet is done gradually rather than overnight.

Two groups deserve more caution than the average animal. A pet on a prescription diet for kidney, urinary, liver or allergy problems can have the whole point of that diet undone by the wrong scrap, so ask the vet what's compatible before sharing anything. And a pet being investigated for a food allergy needs its diet kept genuinely clean during the trial, which means nothing at all from the table for the duration — a single piece of cheese can cost you the answer.