How Many Calories Should a Shih Tzu Eat?

Calculating daily calories: the RER method

Resting energy requirement (RER) = 70 × (body weight in kg)^0.75. For an adult Shih Tzu at common weights: a 4 kg dog has an RER of about 220 calories; a 5.5 kg dog has an RER of about 285 calories; a 7 kg dog has an RER of about 340 calories. These are calories at complete rest — not the amount to actually feed.

The maintenance energy requirement (MER) is RER multiplied by a life-stage factor. For a neutered adult Shih Tzu at low activity, a multiplier of approximately 1.2–1.4 is appropriate per WSAVA guidelines. That gives a daily feeding target of roughly 265–310 calories for a 4 kg dog, 340–400 calories for a 5.5 kg dog, and 410–475 calories for a 7 kg dog. These are broad starting estimates — the right amount for your individual dog is confirmed by monitoring body condition over 4–6 weeks and adjusting if needed.

How activity level and life stage change the number

Shih Tzus have a low to low-moderate activity level per their breed profile, so the lower end of the multiplier range (1.2–1.4) applies to most adult Shih Tzus living typical companion lives with two short daily walks. An unusually active individual — one that plays vigorously indoors or attends regular training sessions — might use a multiplier closer to 1.6.

Intact (unspayed/unneutered) Shih Tzus need somewhat more calories than spayed/neutered individuals — AAHA guidelines note that neutering can reduce caloric needs by 15–30% in some dogs. Many Shih Tzu owners notice weight gain in the months after the procedure if portions are not adjusted downward at that time.

Puppies need substantially more calories per kilogram than adults — up to 2–3 times as much relative to body weight during rapid growth phases. Senior Shih Tzus (roughly 9 years and older) typically need fewer calories as activity and metabolic rate decline. A 10-year-old Shih Tzu living quietly may need 15–20% fewer calories than the same dog needed at age 3.

Treats and extras: the hidden calorie drain

For a breed with a daily budget of 300–400 calories, even small treats add up fast. A single medium-sized commercial dog biscuit can represent 30–50 calories — 10–15% of a day's total for a small Shih Tzu. WSAVA guidelines recommend keeping treats to no more than 10% of daily caloric intake. On days with training treats or human food extras, reduce the main meal portion proportionally.

A practical approach: measure treats by calories, not by number. Small, soft training treats in the 2–5 calorie range allow more pieces without busting the budget compared to large, dense biscuits. Always check the calorie count on the treat packaging and count them against the daily total.

Common mistakes and a note on vet guidance

The most common calorie mistake with Shih Tzus is relying on bag feeding guides without adjustment. Bag guides are typically calculated for intact adults at moderate activity — they generally overestimate for a spayed/neutered, low-activity Shih Tzu. Using the RER-based estimate, or a calorie calculator, and then adjusting based on body condition over 4–6 weeks is more accurate.

A second common mistake is not accounting for how many times the dog has eaten treats throughout the day. Treats given by multiple family members can easily push total intake well above the meal-based calculation without anyone realizing it. Keeping a single-day tally occasionally is a useful calibration exercise.

If your Shih Tzu has a health condition — including thyroid issues, diabetes, or kidney disease — do not rely on general calorie formulas alone. Consult your veterinarian or a board-certified veterinary nutritionist for a tailored plan. These conditions can substantially alter appropriate caloric and nutrient targets.