Cat Food Guide + Feeding Calculator

Foods cats can’t eat — the complete guide

Cats are obligate carnivores, and their nutritional needs are genuinely different from a dog’s. Foods that are fine for a dog can be dangerous for a cat, which is why the list is worth knowing.

Foods that are worse for cats than for dogs

Onion, garlic and scallions hit cats harder than dogs. Cats are more sensitive to the compounds that destroy red blood cells, and even trace amounts in broth or powder count. Thiaminase in raw fish is another risk specific to cats.

Cats and tuna

Cats love tuna, but it should never be the main diet. Fed regularly it leads to mercury buildup and yellow fat disease (steatitis). Keep it to a treat — under 10% of total calories.

Cat food calculator — using cat-specific energy factors

Cat portions need cat-specific factors, not dog ones. A spayed or neutered indoor cat has a notably lower metabolism and puts on weight fast if overfed.

Cat DER factors (daily energy requirement)

• Kitten (under 1 year): RER × 2.5 — growth takes a lot of energy
• Spayed/neutered adult (average build): RER × 1.2 — the range where weight creeps up
• Intact adult: RER × 1.4 — burns noticeably more
• Senior: RER × 1.1-1.3 — slower metabolism, smaller portions

Dry food vs. wet food

Dry food runs about 350 kcal per 100 g; wet food about 70-100. The same weight of food delivers wildly different calories, so the food type has to go into the math. Wet food also raises water intake, which helps the kidneys.

Source: AAHA — 2021 Nutrition and Weight Management Guidelines for Dogs and Cats

Frequently asked questions