Your dog used to eat anything that hit the bowl. Now breakfast sits there until lunchtime, dinner gets a sniff and a walk away, and you have started adding things to get it eaten.
Start here, before the feeding advice
Appetite is one of the clearest health signals you have, so it gets checked first. Sudden behaviour change warrants a veterinary examination, and pain frequently presents as a change in behaviour rather than as obvious lameness. A dog who refuses 2 meals in a row is a phone call today. Do not wait to see whether a new routine helps.
Safety note
Call your veterinary practice today if your dog has refused 2 meals in a row, has eaten nothing for 24 hours, or is losing weight. Call today as well for vomiting, diarrhoea, drooling, pawing at the mouth, dropping food while eating, or a dog who has gone quiet and flat. Sudden behaviour change warrants a veterinary examination, and pain often presents as a change in behaviour rather than as obvious lameness. A puppy or a small dog goes downhill faster than an adult, so do not leave that call until tomorrow.
Then count everything else your dog eats
This is where most fussiness turns out to live. Training treats, chews, a dental stick, the children's crusts and a spoon from the counter add up. That is a meal your dog has already had.
Write down every single thing your dog eats for 2 days, including what other people in the house hand over.
Take the training food out of the daily ration rather than adding it on top. Most of a Session can be paid from the bowl.
Stop the toppings for a week. A dog who waits for something better on the food has learned that waiting works.
Put the meal down for 15 minutes, lift it without comment, and offer the next one on time. No additions in between.
What else changed around the bowl
Where it is. A bowl in the middle of a busy kitchen, or near the other dog, is a hard place to eat slowly.
When it is. A dog fed straight after a walk or a game is often still too wound up to eat. Feed after 30 minutes of quiet instead.
Who is standing there. Watching over the bowl puts pressure on the meal. Put it down and leave the room.
What is in it. A new bag, a new batch, or hot weather can all move appetite. Change food gradually rather than overnight.
Growth slows, and so does appetite
Many dogs eat less from around 9 to 12 months than they did as puppies. They are no longer growing at the same rate. Ask your veterinary practice what your dog should be eating at their current weight.
Do not try to out-wait a dog into eating. Skipping meals to prove a point is not something we would ask you to do. It turns a health question into a longer one.
Use the food you have
A dog who leaves dinner in the bowl is often still keen to work for the same food from your hand. Reward-based methods are what the veterinary behaviour guidance recommends, and the ration is the cheapest way to pay for them.
Hand-feed a portion during a 3 minute Session, scatter a portion in the grass, and put the rest in a food toy. Behaviour change is built from management plus reinforcement, and so is a dog who finishes their dinner.
Today's version, in one line: write down everything your dog eats today, and put dinner down for 15 minutes with nothing added.