Feeding guidelines on kibble bags are written for intact, active, young dogs — and most pets are none of the three. The veterinary RER/MER framework gives you the actual number, and the 10% treat rule keeps you honest about where calories hide.
1. RER: The Baseline Every Bowl Is Built On
The Resting Energy Requirement is the calories a dog burns at rest in a thermoneutral room — the canine BMR. The formula is allometric, not linear: metabolism scales with body weight to the 3/4 power, so a 40 kg dog needs far less than double a 20 kg dog.
// Resting Energy Requirement (kcal/day)
RER = 70 * (weight_kg ^ 0.75)
//
// MER = RER * life-stage factor
// neutered adult 1.6 | intact adult 1.8
// puppy 0-4 mo 3.0 | puppy 4-12 mo 2.0
// weight loss 1.0 | senior 1.4
// working dog 2.0-5.0 (by intensity)
//
// 20 kg neutered adult: RER = 70*20^0.75 ≈ 662, MER ≈ 1,060 kcalThis nonlinearity is why per-kg feeding charts on bags mislead: they assume a straight line through a curved relationship. RER is the correct starting point — but it is a resting number, and no living dog is a resting number.
2. MER: The Life-Stage Multiplier That Decides Everything
The Maintenance Energy Requirement multiplies RER by a factor for the dog your dog actually is. The spread is enormous: a neutered adult needs 1.6× RER; an intact adult 1.8×; a puppy under 4 months 3×; a dog on a vet-supervised weight-loss plan just 1.0×.
Two dogs of identical weight can differ by 2–3× in legitimate calorie needs. "How much should I feed?" has no answer until you answer: which dog — age, neuter status, activity, body condition?
Dog Food CalculatorRER → MER with the correct life-stage factor, converted to grams of your specific food from its kcal/kg label.→3. From Calories to Grams: Read the Label Like a Vet
Calorie targets are useless until converted to the food in your cupboard. Pet foods list energy as kcal/kg (or kcal/cup) — typical kibble runs 3,400–4,200 kcal/kg. A 20 kg neutered adult needing ~1,060 kcal/day eats roughly 280 g of a 3,800 kcal/kg kibble — and that is total, including everything else the dog eats that day.
Weigh food with a kitchen scale, not a scoop: studies of owners using measuring cups find portions drift 20–80% from target. A $10 scale is the single highest-ROI purchase in canine weight management.
4. The 10% Treat Rule and the Body Condition Score
Treats, chews, table scraps, and training rewards together must stay under 10% of daily calories — and they count inside the MER, not on top of it. A dental chew can run 60–90 kcal; five training treats at 8 kcal add 40. On a 1,060 kcal budget, that is already the entire treat allowance before dinner.
Then verify the plan against the dog, not the spreadsheet: the Body Condition Score (1–9 scale) is the field instrument. Ribs palpable under a thin fat layer, visible waist from above, tucked abdomen from the side — that is a 4–5. If you cannot feel ribs without pressing, the MER factor you chose was too generous; adjust intake down 10% and re-score in 3 weeks.
5. Age Is a Feeding Variable: The Human-Years Myth
The "multiply by 7" rule fails because dogs mature fast early and slow later: a 1-year-old dog is roughly 15 in human years; year 2 adds about 9; each year after adds 4–5. What matters for feeding is the life stage that mapping exposes — the puppy multiplier (3.0×) ends around 12 months (18–24 for giant breeds), and the senior factor kicks in around 7+ as activity and lean mass decline.
Feeding the same cup from age 2 to age 12 is why middle-aged dogs drift overweight: the factor moved and the bowl didn’t.
Dog Age CalculatorSize-aware human-year mapping with life-stage flags — know when the puppy factor ends and the senior adjustment begins.→The Monthly Weigh-In Protocol
- Compute RER → MER with the right life-stage factor; log the target.
- Convert to grams of your actual food from its kcal/kg label; weigh every meal.
- Cap treats+chews at 10% inside the budget, not on top.
- Weigh the dog monthly; adjust ±10% on any sustained trend — wait 3 weeks before judging a change.
- Re-run the factors at every life-stage transition (spay/neuter, 12 months, ~7 years).
Any unexplained weight change on stable intake, or a BCS drifting outside 4–5/9, earns a vet visit — the math guides feeding, it does not diagnose.