About 56% of US pet dogs are overweight or obese. Excess weight is linked to shorter lifespan, joint disease, diabetes, heart problems and a measurable reduction in daily quality of life. The good news: dogs respond very well to structured weight-loss programs — most dogs can reach an ideal body condition in 12-24 weeks with a simple, consistent approach.
This is the 12-week framework veterinary nutritionists most often recommend, adapted for at-home use.
What's in this guide
1. Before you start: set the target
You need three numbers before week 1:
- Current weight — weigh at the vet, or at home (weigh yourself, then yourself holding the dog, subtract).
- Body Condition Score — see our 60-second BCS guide.
- Estimated ideal weight — for each BCS point above 5, ideal weight is about 10% lower than current. A 30 kg dog at BCS 7 has an ideal weight of about 25 kg.
Write these down. Take a photo from above and from the side. You'll want them for comparison.
2. How many calories for weight loss
For weight loss, calculate calories based on ideal weight, not current weight, using a 1.0× RER multiplier. For our 30 kg dog with a 25 kg ideal:
RER = 70 × 250.75 = 70 × 11.18 = ~783 kcal/day
That's substantially less than this dog's current maintenance — and that gap drives the weight loss. The PawPortion dog calculator does this math automatically when BCS is above 5.
The right rate: 1-2% per week
Aim for losing 1-2% of current body weight per week. For our 30 kg dog: 0.3-0.6 kg per week, or roughly 4-7 kg over 12 weeks. Anything faster sacrifices muscle and slows metabolism.
3. The 12-week schedule
| Week | Focus | Action |
|---|---|---|
| 1 | Baseline | Weigh, photograph, score BCS. Switch to measured meals. Start calorie target. |
| 2 | Adapt | Continue exact portions. Track daily activity (steps or minutes). |
| 3 | Check in | Re-weigh. Expect 1-3% loss. Photograph from above. |
| 4-5 | Plateau watch | Loss may slow. Don't cut more yet — stay the course. |
| 6 | Halfway re-weigh | If progress is < 2% in last 3 weeks, reduce calories another 10%. |
| 7-8 | Boost movement | Add 10-15 min daily walk or one new activity per week. |
| 9 | Re-score BCS | Should be visibly improving. Re-photograph. |
| 10-11 | Maintain | No big changes. Stay disciplined with treats. |
| 12 | Reassess | Full re-evaluation. If at BCS 5, transition to maintenance calories. |
Per-meal feeding tips
- Split into more meals. Three smaller meals instead of two stabilises energy and reduces begging.
- Slow feeders / puzzle bowls. Stretches the meal duration; reduces "I'm still hungry" behaviour.
- Use kibble as training treats. Counts toward daily total, costs zero extra calories.
- Substitute high-calorie treats with vegetables. Carrots, green beans, cucumber, broccoli — most dogs accept these readily.
4. Handling the week 4-6 plateau
Almost every dog hits a stall around week 4-6. The body has adapted to the lower calorie intake by slightly reducing baseline metabolism. Don't panic and slash calories. Instead:
- Audit treats and human food. Plateaus often turn out to be hidden calories.
- Re-measure portions. "About a cup" can drift to "a heaping cup" over weeks.
- Increase movement before cutting more food. A 15-minute longer walk often restarts progress without further restriction.
- Only if no progress after 2 weeks of strict tracking — reduce daily calories by 10% and re-check in 2 weeks.
5. Keeping the weight off
Hitting BCS 5 is the start, not the end. About 50% of dogs regain weight within 12 months. To stay there:
- Re-calculate maintenance calories at the new lower weight (it's lower than you think).
- Keep the measuring cup or scale in use forever.
- Re-check BCS monthly.
- If weight creeps up 5%, immediately drop back to weight-loss calories for 2-3 weeks.
6. When to see the vet
See a veterinarian before starting if:
- Your dog is BCS 8 or 9 (severe obesity needs medical supervision)
- Your dog is over 10 years old or has known health issues
- Weight gain has been sudden or unexplained (possible thyroid, Cushing's or other conditions)
- Your dog is on medication
And during the plan, contact your vet if you notice unusual thirst, lethargy, vomiting, or rapid weight loss (more than 2% per week).
Use the calculator to get your starting number
Set BCS to 6, 7, 8 or 9 in the dog calorie calculator and we'll output your weight-loss daily kcal target instantly, based on the same math vets use.
The bottom line
Dog weight loss isn't complicated — it just requires consistency. Get the target calorie number right, measure every meal, track every treat, walk daily, and re-check progress every 2-3 weeks. Most dogs see noticeable change within 4-6 weeks, and a transformed dog by week 12.