How much should I feed my dog? Start with the dog, not the bag

There's no correct number of grams that applies to a dog of a given weight.

Two dogs the same size, the same age and the same breed can need portions that differ by a third, because their activity, their metabolism and whether they've been neutered all move the requirement. This is why every honest answer to this question starts in the same place: feed a sensible starting amount, then let the dog tell you whether it was right.

Why the bag over-feeds most dogs

The feeding guide on the packet isn't wrong so much as generic.

It's calculated for an unneutered adult of a stated weight at moderate activity, and it's usually printed as a range with the household reading the top of it. Most pet dogs are less active than that model, and neutering lowers energy requirements noticeably — so the packet figure lands high for a large share of the dogs it's fed to.

Treat it as an opening bid. Start at or slightly below the lower end of the range for your dog's ideal weight instead of its current weight, and then adjust by what you see over the following weeks.

The measurement that matters: body condition

Vets score dogs on a body condition scale instead of by weight alone, because weight without shape tells you very little. You can do the same assessment at home with your hands, and it takes about fifteen seconds.

Ribs. Run your fingertips flat along the side of the chest with light pressure. You should feel each rib easily, with a thin covering over it — the texture of the back of your own hand. If you have to press to find ribs at all, the dog is carrying too much. If the ribs are sharp and visible from across the room, too little.

Waist. Look down at the standing dog from above. There should be a visible narrowing behind the ribs. A straight line from chest to hips, or a widening, means excess weight.

Tuck. Look at the dog from the side. The belly should rise from the bottom of the ribcage towards the hind legs rather than running level.

Two breeds-worth of caveats are worth holding. A very hairy dog hides all three checks, so the hands matter more than the eyes; and a few builds are exceptions by design — a greyhound's ribs show on a perfectly healthy dog, and a bulldog has no waist to speak of. If you're unsure what your particular breed should feel like, a nurse at the practice will show you in two minutes, and it's a free appointment at most surgeries.

Do this once a fortnight, not once a year. Weight gain in a dog is invisible day to day and obvious in a photograph taken six months apart, which is why it so often goes unnoticed until a vet mentions it.

Weigh the food; do not scoop it

A scoop isn't a unit.

The same cup of the same kibble varies substantially between fillings depending on how it settles, and a household that eyeballs portions is usually drifting upwards and not downwards. Kitchen scales cost very little and remove the entire problem, and they also make it possible to change a portion by a real ten per cent instead of by a guess.

If more than one person feeds the dog, agree the amount in grams and write it on the bin. A dog fed twice because nobody said so is the most common overfeeding accident in a busy house.

Weigh the day's total in the morning if that's easier — into a tub, with the meals and the training treats coming out of it — so the figure is fixed before anyone starts improvising. It takes ten seconds and it converts a daily judgement into a daily fact.

How many meals, and when

Twice a day suits most adult dogs, and the timing matters less than the consistency.

Puppies need more: roughly four meals a day while very young, dropping to three and then two as they grow, because a small stomach can't hold a day's calories at once. Very old dogs sometimes do better on three smaller meals again, particularly if they're nauseous or on medication that wants food with it.

One meal a day is enough for many dogs but leaves a long empty stretch, and some dogs bring up bile in the early morning as a result — splitting the ration usually fixes that on its own. At the other end, free-feeding a bowl left down all day makes portion control impossible, hides a lost appetite that would otherwise be an early warning, and suits almost no dog.

For deep-chested breeds there's a further reason to split meals and to avoid hard exercise immediately before or after one: large single meals eaten fast are associated with bloat, which is a genuine emergency in those dogs. A slow-feeder bowl is a cheap precaution for any dog that inhales its food.

Treats are food, and they add up faster than anyone expects

The portion you've carefully weighed is only part of what the dog eats.

Training treats, chews, the end of a sandwich and what falls off a high chair all count, and the usual guidance is that treats should stay a small minority of daily intake with the rest coming from a complete food. If you're training intensively, take the treat allowance out of the meal instead of adding it on top — see how many treats is too many for the arithmetic.

How to correct a portion that is wrong

Change food quantity slowly and one variable at a time.

If the dog is heavier than it should be, cut the daily amount by around ten per cent, hold it there for a month, and reassess by body condition instead of by the scales alone. Ten per cent is small enough not to leave the dog hungry and large enough to move the needle over weeks.

If a reduced portion leaves the dog genuinely ravenous and not merely opinionated, bulk it out instead of giving in: a handful of green beans, a little plain cooked pumpkin or some courgette adds volume for almost no calories, and a slow-feeder or puzzle bowl makes the same quantity last three times as long. A dog that has finished in forty seconds feels unfed however much was in the bowl.

Weight loss in dogs should be gradual. A crash reduction is unkind, it costs muscle as well as fat, and in cats it's genuinely dangerous. If a dog needs to lose a significant amount, that's a conversation with a vet instead of a project to run alone — partly because a sudden change in weight or appetite can itself be a symptom rather than a diet problem.

What changes the number

Age. Puppies of large breeds are their own subject, because growing too fast is a joint problem and not a benefit — see feeding a large breed puppy. Older dogs generally need fewer calories and often benefit from a different formulation, covered in feeding senior pets.

Neutering. Energy requirements drop after neutering, and portions frequently don't. This is one of the most reliable causes of a dog gaining weight in its second year.

Season and workload. A dog that walks two hours a day in summer and forty minutes in winter isn't the same dog nutritionally. Adjust for the winter rather than discovering it in spring.

The food itself. Calorie density varies enormously between products, so grams of one food aren't grams of another. Every switch is a recalculation, not a substitution — and the switch itself should be gradual, as changing a pet's food explains.

Health and medication. Some conditions and some drugs change appetite or energy use markedly, and a few — steroids in particular — make a dog genuinely hungrier. If a portion that worked for years suddenly doesn't, that's worth mentioning to the vet rather than adjusting around.