The bag says puppy up to 12 months. Your dog is 10 months old, looks fully grown, and eats like they are still growing. So you are standing in the aisle guessing.
This is a nutrition and growth question rather than a behaviour one, and it has a right answer for your particular dog. We are not going to invent it for you.
Ask the one question that settles it
Ask your veterinary practice, at the next appointment or by phone: what should this dog be eating, how much, and when should the food change. They can weigh your dog and score their body condition.
Bring the bag, or a photo of the label, and your dog's current daily amount. Include the treats and chews in that number, because they are part of the ration.
Large and giant breed dogs finish growing later than small ones, so timing is not one date for every dog. Your practice knows what your dog weighed at each visit, which is the thing a bag cannot know.
What to have ready for that call
Your dog's current weight, and what they weighed at their last 2 appointments.
The exact food, the exact daily amount, and how many meals a day.
Every treat, chew, dental stick and leftover that anyone in the house hands over on a normal day.
Whether your dog has been neutered, and when, because that can change what they need.
Anything you have noticed about their appetite, their stools, their coat or their energy.
Change food gradually, whenever you do it
Whatever date you land on, move across over about a week rather than overnight. Mix a little of the new food into the old, and increase the proportion each day.
Days 1 to 2: a quarter new food, three quarters old, at each meal.
Days 3 to 4: half and half.
Days 5 to 6: three quarters new food.
Day 7 onward: all new food, at the amount your veterinary practice gave you.
Slow down or go back a step if the stools loosen, and call your practice if that does not settle.
Where this touches training
Reward-based methods are what the veterinary behaviour guidance recommends, and the daily ration is the cheapest way to pay for them. Take the training food out of the bowl rather than adding it on top.
A 3 minute Session, a scatter feed in the grass and a food toy can all come out of one measured meal. That keeps the total honest while your dog still gets paid.
One practical note about the switch itself: do not start it in the same week as a house move, a boarding stay or a course of medication. Change one thing at a time so you know what caused what.
Safety note
Call your veterinary practice today if your dog refuses 2 meals in a row, eats nothing for 24 hours, is losing weight, or is vomiting or has diarrhoea. Sudden behaviour change warrants a veterinary examination, and pain frequently presents as a change in behaviour rather than as obvious lameness. Do not put a dog who is unwell onto a new food while you wait for that appointment.
What not to do while you wait for the appointment
Do not cut the amount to slim your dog down without asking first. A growing dog on short rations is a different problem.
Do not add supplements, calcium or raw toppings on the strength of a forum post.
Do not switch twice in a fortnight because the first change looked unsettled. Give a week, then ask.
Do not free-feed a bowl left down all day. Measured meals are what let you notice a change in appetite.
Behaviour change is built from management plus reinforcement, and feeding is management. A dog on a settled routine, with a measured amount, is easier to train than one whose day is a guess.
If the real question is why your dog has become difficult about food rather than what is in the bowl, the Assessment will sort which part to work on first. It is free and takes about 3 minutes.
Today's version, in one line: weigh out tomorrow's food, write down every extra your dog gets, and phone your practice with both numbers.