Arrive with the result, leave with a plan
Early kidney or liver changes on blood work often sound more alarming than the appointment needs to be, but diet questions only get useful answers when they are specific. Take the actual results with you, or have them open on your phone, and be ready to say what your dog currently eats in real detail: the main food, how much per day, treats, chews, supplements and anything he scavenges. Diet advice built on a vague description of his intake will be vague in return.
Open with the values themselves. Ask which numbers moved, how far they moved, and whether they suggest a feeding change now, a planned change if the trend continues, or simply monitoring. That distinction matters: early changes sometimes call for adjustment and sometimes for watchful waiting, and you want to know which situation your dog is actually in before you change anything at home.
The feeding questions worth asking, in order
First, the goal. Ask what the diet is meant to achieve for this organ and this dog: reducing the workload on kidneys, supporting a liver that is processing less efficiently, maintaining muscle and weight, or some combination. A stated goal makes every later choice easier to judge, including treats.
Second, the specifics. Ask what the new feeding should emphasise and, just as importantly, what he should now avoid or have only in limited amounts, including common treats, chews and table foods that families forget to mention. Ask whether his current food can be adjusted or needs replacing, and why.
Third, the transition and the proof. Ask how quickly to move from the old food to the new, since abrupt switches upset many stomachs, and what to do if he refuses the new diet, which is a real possibility with dogs who feel nauseous or simply know their own preferences. Then ask when blood work should be repeated and which values you are watching, so the recheck tests whether the plan is working rather than merely passing time.
Questions owners forget until the drive home
Ask about water: whether intake should be encouraged, measured, or simply watched, and what change in drinking or urination should prompt a call sooner than the recheck. Ask about appetite: what to do on days he will not eat, and at what point poor appetite becomes a reason to ring rather than wait. Ask whether anything else he takes, including supplements and joint products, should be reviewed alongside the diet, because the vet can only judge interactions they know about.
Also ask who else needs the plan. If family members, a walker or a sitter feeds him, everyone needs the same rules, especially about treats, which is where careful diets quietly unravel. A one-page summary you can share is worth requesting before you leave.
Making the plan survive ordinary life
Write down the answers during the appointment, including the recheck date, and read them back to the vet before you go; corrections happen easily in the room and rarely afterwards. At home, put the feeding rules where food is prepared, weigh or measure portions consistently, and note appetite, drinking and energy in a simple daily line for the first weeks, since those observations are exactly what the recheck conversation will ask about.
Contact the practice sooner than planned if he stops eating, vomits repeatedly, drinks or urinates dramatically more, or seems unusually tired or disoriented, rather than waiting for the scheduled bloods. Storing the diet plan, the values you are watching and the recheck date in his KinsLe Pet Passport keeps the whole household, and any vet who sees him next, working from the same page.