Key Takeaways
- Keep your new pet on their previous food for at least one to two weeks before making any changes.
- Look for an AAFCO nutritional adequacy statement to confirm a food is complete and balanced.
- Puppies, kittens, adults, and seniors have distinct nutritional needs that require life-stage-specific formulas.
- Scheduled meals with measured portions help prevent obesity and make health monitoring easier.
- Several common human foods — including grapes, xylitol, and chocolate — are toxic to dogs and cats.
Start here
Start With What Your Pet Was Eating Before
Next
How to Read a Pet Food Label
Then
Life-Stage Nutrition: Why Age and Size Matter
When you're ready
Feeding Schedules and Portion Sizes
Safety check
Foods to Avoid and When to Call Your Vet
Start With What Your Pet Was Eating Before
One of the most common first-time owner mistakes is immediately switching a new pet to a different food. Even if you have concerns about the previous diet, an abrupt change can cause digestive upset — vomiting, loose stools, and discomfort — because a pet's gut microbiome needs time to adjust to new ingredients.
Ask the breeder, rescue organization, or shelter what the pet was eating, the brand, formula, and serving size. Continue that exact food for at least one to two weeks after bringing your pet home. This gives your new companion time to settle into their environment without the added stress of a dietary change.
If you decide a different food is more appropriate, transition gradually over seven to ten days by mixing increasing amounts of the new food with decreasing amounts of the old. Our guide on transitioning your pet to a new diet without digestive upset walks through this process step by step.
Ask Before You Leave the Shelter
Before bringing your pet home, ask for a small supply of the food they have been eating — even just enough for a few days. Many shelters and breeders will provide this at no cost. Having the exact food on hand prevents a forced immediate switch and gives you a reference point for comparison shopping later.
How to Read a Pet Food Label
Pet food labels contain regulated information that tells you a great deal about nutritional quality — if you know what to look for. The single most important thing to find is the AAFCO nutritional adequacy statement. This tells you whether the food is formulated to meet established nutrient profiles for a specific life stage (such as growth, adult maintenance, or all life stages) or whether it has only been tested through feeding trials.
Beyond that statement, check the guaranteed analysis panel, which lists minimum percentages of crude protein and fat, and maximum percentages of fiber and moisture. The ingredients list is ordered by weight before processing, so named protein sources (such as chicken or salmon) appearing near the top are a good sign.
For a deeper breakdown of what those numbers and terms actually mean, see our article on pet nutrition labels decoded.
AAFCO
The Association of American Feed Control Officials — a standard-setting body whose nutritional profiles are used to determine whether a pet food is 'complete and balanced' for a given life stage.
Guaranteed Analysis
A panel on pet food packaging listing the minimum or maximum percentages of key nutrients like protein, fat, fiber, and moisture — required by law on all pet food labels in the US.
Life-Stage Formula
A pet food formulated to meet the specific nutritional needs of a particular phase of life, such as growth (puppies/kittens), adult maintenance, or senior care.
Body Condition Score (BCS)
A standardized assessment tool used by veterinarians and owners to evaluate a pet's weight and fat coverage, typically rated on a 5- or 9-point scale from underweight to obese.
Obligate Carnivore
An animal — such as a cat — that must obtain certain essential nutrients from animal tissue because it cannot synthesize them adequately from plant sources.
Taurine
An amino acid that cats cannot produce in sufficient quantities on their own and must get through their diet; deficiency can cause serious heart and eye problems.
Life-Stage Nutrition: Why Age and Size Matter
A food that is appropriate for an adult dog is not nutritionally suitable for a growing puppy, and the same principle applies to cats. Life-stage formulas exist because energy requirements, calcium-to-phosphorus ratios, protein density, and certain micronutrients vary significantly across an animal's life.
- Puppies and kittens need calorie-dense food with higher protein and fat to support rapid growth, immune development, and brain maturation.
- Adult pets require a maintenance formula calibrated to sustain healthy weight and organ function without excess calories.
- Senior pets often benefit from adjusted protein levels, added joint-support nutrients, and reduced caloric density as metabolism slows.
- Large-breed puppies have specific calcium and phosphorus requirements to support controlled bone growth; standard puppy food can lead to skeletal problems in these breeds.
Our companion guide pet nutrition from puppyhood to senior years covers each phase in detail, including what to watch for as your pet ages.
Feeding Schedules and Portion Sizes
Free-feeding — leaving food out all day — is convenient but makes it difficult to monitor how much your pet is actually eating and can contribute to weight gain. Scheduled meals with measured portions are the approach most veterinary nutritionists recommend for healthy adults.
Start with the serving guidelines on the food packaging, which are based on target body weight. Use a kitchen scale or a dedicated measuring cup rather than estimating by eye. Then assess your pet's body condition score (BCS) — a scale used to evaluate whether a pet is underweight, at an ideal weight, or overweight — every few weeks and adjust portions accordingly.
For puppies and kittens under six months, three to four meals per day is typical. Most adult dogs and cats do well on two meals daily. Consistency in timing helps regulate digestion and makes it easier to notice early if appetite changes — which can be an important health signal.
Learn more about calibrating portions in our article on portion control and weight management in pets.
Avoid Eyeballing Portion Sizes
Studies in veterinary nutrition consistently show that owners significantly underestimate or overestimate serving sizes when scooping by eye. Even a small daily excess adds up over months and can contribute to overweight and the health conditions associated with it. Use a kitchen scale for dry food whenever possible, and measure wet food with a proper measuring tool.
Foods to Avoid and When to Call Your Vet
Several everyday human foods are toxic to dogs and cats. Knowing this list is a basic safety requirement for every pet owner.
- Dogs: grapes and raisins, xylitol (a sweetener found in sugar-free gum, some peanut butters, and baked goods), chocolate, onions, garlic, macadamia nuts, and alcohol.
- Cats: onions and garlic, raw fish fed regularly (can deplete thiamine), xylitol, alcohol, and caffeine.
If you suspect your pet has ingested any toxic substance, contact your veterinarian or an animal poison control hotline immediately — do not wait for symptoms to develop.
More broadly, your vet is your best resource for feeding questions. The first 30 days veterinary care roadmap is a useful companion guide for scheduling that first wellness visit, where you can confirm your feeding plan is appropriate for your specific pet's breed, size, and health status.
This article is for general informational purposes only and does not constitute veterinary or nutritional advice. Always consult a licensed veterinarian for guidance specific to your pet's health and dietary needs.