Roughly 60% of US pet cats are now overweight or obese. The single biggest cause isn't treats, isn't a slow metabolism, and isn't laziness — it's the gap between the cup chart on a dry-food bag and what a real indoor neutered cat actually needs.
The rule that fixes this is surprisingly simple. Here it is in one line, with the rest of the article explaining why it works and how to use it.
A typical indoor neutered adult cat needs about 40–55 kcal per kilogram of ideal body weight per day.
What's in this guide
1. The quick math
For a healthy 4.5 kg (≈10 lb) neutered indoor cat:
4.5 kg × 45 kcal = ~200 kcal/day
That's it. The full RER × multiplier formula gives the same number with more precision, but the linear shortcut works because most pet cats fall within a narrow weight range.
2. Why bag feeding charts overfeed cats
Look at a typical dry cat food bag. For a "4–5 kg adult cat" it might recommend ½ to ¾ cup per day. Sounds reasonable. But that food contains 380–450 kcal per cup. Do the math:
- ½ cup × 400 kcal = 200 kcal ✅ (correct for an indoor cat)
- ¾ cup × 400 kcal = 300 kcal ⚠️ (50% too much)
The bag's high end works for an active outdoor or intact cat. The low end works for an indoor neutered cat. Most owners aim for the middle — and that middle is precisely the calorie surplus that produces feline obesity.
Cats are different from dogs
Cat metabolism is closer to a small carnivore that catches several small meals a day. They don't have the same "I'll-eat-anything" appetite regulation problems as dogs — they overeat dry food specifically because it's calorie-dense and palatable in a way wet prey never was.
3. Quick-reference cat feeding table
For neutered, indoor adult cats at ideal body condition:
| Cat weight | Daily calories | Wet food (≈90 kcal/can) | Dry food (≈400 kcal/cup) |
|---|---|---|---|
| 3.0 kg / 6.6 lb | 140 kcal | 1.5 cans | ⅓ cup |
| 3.5 kg / 7.7 lb | 160 kcal | 1.8 cans | ⅖ cup |
| 4.0 kg / 8.8 lb | 180 kcal | 2.0 cans | ½ cup (scant) |
| 4.5 kg / 9.9 lb | 200 kcal | 2.2 cans | ½ cup |
| 5.0 kg / 11 lb | 220 kcal | 2.4 cans | ⅗ cup |
| 5.5 kg / 12 lb | 240 kcal | 2.7 cans | ⅔ cup |
These numbers assume body condition score 5/9. If your cat is overweight, work with the ideal weight — not the current weight.
4. Wet vs dry: portion math is easier with wet
Cans of wet food are pre-portioned and almost always come with a stamped kcal value. That makes feeding by-the-can simple: 2 cans of a 90-kcal food = 180 kcal, no measuring required.
Dry food requires a measuring cup (not a coffee mug or a yogurt container — a real measuring cup), every meal, every time. Most "overfeeding" in cats traces back to imprecise dry-food scooping.
5. Five-minute portion fix
- Weigh your cat (carrier on a scale, minus the empty carrier weight).
- Check the body condition score — pick the silhouette in our cat calculator that matches.
- Find the kcal/cup or kcal/can on your food's bag.
- Use our calculator or the table above to find your cat's daily kcal target.
- Divide that into 2–4 meals. Use a measuring cup or kitchen scale.
Going slow if your cat needs to lose weight
Cats cannot safely lose weight as fast as dogs. Even a few days of insufficient food intake can trigger hepatic lipidosis — a life-threatening fatty liver condition. Aim for no more than 0.5–1% body weight per week, and work with your vet for any cat above BCS 7.
The bottom line
Feeding cats well isn't about exotic diets or expensive food. It's about getting the daily calorie number right and serving it in a way that gives them small, predictable meals throughout the day. Use the formula. Measure. Re-check every few weeks. Most cats lose their "spare tire" within 6–12 months.