A protein change really can affect how much your dog drinks, mainly through moisture content and the nitrogen the body must excrete. More protein means more urea to flush out, and that takes water. But increased thirst is also an early sign of several medical conditions, so a sustained change needs a veterinary check rather than a dietary explanation.
The two food related mechanisms
The first is moisture, and it is the larger of the two. Dry food contains around ten percent water. Gently cooked and fresh foods typically contain far more, often the majority of their weight. A dog moving from one to the other experiences a large change in how much water arrives with dinner rather than from the bowl.
The direction matters. Moving from dry food to fresh food usually means a dog drinks noticeably less, because it is getting water in its meal. Moving the other way, or switching between two recipes with different moisture levels, can mean visibly more trips to the water bowl. Owners often read the second as a problem when total water intake has barely changed.
The second mechanism is nitrogen. Protein contains nitrogen, and the body disposes of surplus nitrogen as urea in urine. More dietary protein means more urea to excrete, and excreting urea requires water. A meaningful increase in protein intake therefore produces a modest, genuine increase in both urine output and drinking. This is normal physiology in a healthy dog and not a sign of strain.
Sodium is a smaller third factor. Recipes differ in salt content, and a saltier diet raises thirst. The effect is real but generally modest between complete commercial diets.
How to tell a food effect from a warning sign
This is the part worth getting right, because the two look identical from across the kitchen.
A food related change appears within a few days of the switch, settles into a new steady level, and is not accompanied by anything else. The dog is bright, eating normally, holding weight, and toileting normally apart from a little more urine. It does not keep escalating week after week.
A change worth investigating behaves differently. It builds rather than settling, or appears without any change in diet, or comes with other signs.
Several common conditions in dogs cause increased thirst and urination, including kidney disease, diabetes and hormonal disorders, and some medications do the same. None of those is diagnosed or managed by changing food on your own, and none of them should be self treated. If the pattern in the right hand column fits your dog, the next step is your vet, not a new recipe.
A practical tip for that appointment: measure it. Fill the water bowl with a measured amount, top it up with measured amounts, and note the total over twenty four hours, repeated across two or three days. Do this for every bowl in the house. Your vet can interpret a number far better than an impression, and it converts a vague worry into evidence.
Making a protein change without confusing the picture
Change one thing at a time. If you switch protein, moisture level and brand simultaneously, you have no way of attributing any change to a cause. Move gradually over about a week, mixing increasing proportions of the new food into the old, which also reduces digestive upset.
Keep water freely available throughout and never restrict it to reduce drinking. Restricting water in a dog that is drinking more is genuinely dangerous, because if a medical cause is driving the thirst, the drinking is compensating for water already being lost.
Watch the whole picture rather than the water bowl alone. Appetite, energy, weight, coat and stool together tell you more than any single measure.
What the product page can and cannot tell you
If you are trying to work out whether a recipe explains a change in drinking, you will want moisture content, protein level and sodium. Those figures are not published on the My Perfect Pet website. No guaranteed analysis, ingredient declaration, calorie content or feeding chart appears there. Where they do exist is the printed pack, the Nutrition Facts Sheet PDF attached to each recipe, and the weight calculator on the product page, and the brand will supply specifics in writing if you ask directly. Estimating them from an ingredient list is guesswork, and guesswork is no use to a vet.
What the live product data does show is composition. The Beef Blend is a single protein gently cooked grain free recipe made with beef and beef liver alongside sweet potatoes, potatoes, broccoli, spinach, zucchini, celery, green beans and cranberries. Knowing which animal protein a recipe uses, and whether it is a single protein or a blend, is the useful part when you are changing proteins deliberately and want to keep track of what your dog has eaten.
For broader background on how diet composition relates to a dog's requirements, the American Kennel Club's nutrition resources are a reasonable general reference, though they are no substitute for your own vet knowing your own dog.
The short version
Thirst that rises modestly, quickly and then plateaus after a deliberate protein or moisture change is usually the food, and usually fine. Thirst that keeps climbing, appears out of nowhere, or arrives with other changes is a reason to pick up the phone.
The cost of investigating an increase in drinking that turns out to be dietary is one consultation. The cost of assuming a medical change is dietary can be months of delay. Given that asymmetry, measuring the water and getting it checked is the proportionate response.
Common questions about thirst and protein changes
Can changing a dog's food make it drink more water?
Yes. Moving to a drier food means less water arrives in the meal, so the dog makes up the difference at the bowl. A higher protein diet also produces more urea to excrete, which requires water. Both effects are normal and usually settle within days.
How much water should a dog drink in a day?
A common rule of thumb is roughly fifty to sixty millilitres per kilogram of body weight in twenty four hours, but this varies with diet moisture, exercise and weather. Rather than aiming for a number, measure your own dog's usual intake so you can recognise a change from its own baseline.
Does high protein food make dogs thirsty?
It can, modestly. Excess dietary protein is broken down and its nitrogen excreted as urea, and excreting urea takes water. In a healthy dog this is a normal, small increase in drinking and urination, not a sign the kidneys are struggling.
When should I worry about my dog drinking more?
Contact your vet if the increase continues to build over weeks, appears without any diet change, or comes with weight loss, lethargy, vomiting, a reduced appetite or indoor accidents. Increased thirst is an early sign of several treatable conditions, and earlier assessment gives better options.
Should I limit my dog's water if it is drinking a lot?
No. Never restrict a dog's water to control drinking. If a medical problem is causing water loss, the extra drinking is compensating for it, and taking water away can cause rapid dehydration. Keep water available and arrange a veterinary assessment instead.
Related reading: Beets for Dogs: Color, Fiber and What to Watch and Why Does My Dog Eat Faster on Fresh Food Than on Kibble?