How much to feed a dog to lose weight

Step 1: find the target weight

The calories for weight loss are worked out from the weight your dog should be, so start there. If your vet has given you an ideal weight, use it. If not, a body condition score gets you close: on the 9-point scale, each point above 5 means roughly 10% extra weight. Our guide to checking whether your dog is overweight walks through the scoring with your hands.

Take a 70 lb neutered adult that scores 7. That is about 20% over ideal, so the target is 70 ÷ 1.2, about 58 lb (26.5 kg). We’ll follow this dog through every step below.

Step 2: calories at the ideal weight

The 2021 AAHA Nutrition and Weight Management Guidelines give dogs a weight-loss factor of 1.0 times the resting energy requirement (RER), and tell vets to base the calculation on ideal weight. RER is 70 × body weight in kg to the 0.75 power. For our dog that is 70 × 26.5^0.75, about 817 kcal a day. Feeding for the current 70 lb instead would give an RER of about 936 kcal, and a normal neutered-adult allowance of about 1,500 kcal.

The dog food calculator does this for you: pick a body condition of 7 or more and it works from the estimated ideal weight, showing about 735 to 900 kcal for this dog. Treat the number as a starting point. The Merck Veterinary Manual describes a different starting formula, 60% of the maintenance requirement, and says any calculated intake “is only a starting point” to adjust from the scale.

Step 3: turn calories into food

Calories per cup vary a lot, even between diet foods. When Tufts researchers Linder and Freeman checked 44 dry weight-loss foods for dogs, calorie density ran from 217 to 440 kcal per cup. For our dog’s 735 kcal of food, that is anywhere from about 1.7 to 3.4 cups a day. Read the “Calorie Content” line on your own bag and divide, or let the calculator do it.

If the bag also lists kcal per kg, weighing food on a kitchen scale is the more precise option: divide kcal per kg by 1,000 to get kcal per gram. Split the day’s amount into two or more meals; Merck suggests multiple meals rather than one large one.

Why not just feed less of the same food?

Cutting a normal food far enough to lose weight also cuts vitamins and minerals. VCA Animal Hospitals says it is “not appropriate to simply reduce the volume” of your dog’s current food, because that could lead to deficiencies over time, and Merck says maintenance diets are generally not recommended for weight loss. AAHA recommends therapeutic weight-loss diets, fortified with extra nutrients, once calories go down to RER or below, and says restriction below RER is not recommended with over-the-counter products. Ask your vet which food fits your dog.

Treats, extras and the hungry dog

• Keep treats, chews and table food to 10% of the day’s calories or less. For our example dog that is about 80 kcal.
• Use part of the daily kibble as treats. AAHA suggests separating out a portion of the day’s food for this, so training doesn’t add calories.
• Count vegetables too. AAHA reminds owners that carrots, green beans and other human foods have calories.
• Agree on the plan with everyone who feeds the dog. AAHA notes that owners not sticking to the plan is a major reason weight loss fails.

Weigh, then adjust

Weigh your dog every two weeks on the same scale; that is the interval both Merck and Cornell suggest. Merck calls about 1% of body weight a week a reasonable goal, and Cornell says 1 to 2% a week is safe, which is 0.7 to 1.4 lb for a 70 lb dog. Losing faster can mean calories were cut too far.

If the weight stays the same for a few weigh-ins, first look for hidden calories: extra treats, a second person feeding, or a scoop that holds more than a measuring cup. Then talk to your vet before cutting further. In one large study of a vet-run program (Flanagan et al. 2017), the protocol suggested a 10% cut in calories when a dog lost less than 1% a week, but that was a study rule set by vets, not a home recipe.

Expect a slow, uneven line. In that study of 926 dogs, almost all lost some weight in three months, at an average of 0.9% of starting weight per week, but only 7% reached their target in that time. And keeping it off takes work: in a follow-up of 33 dogs that finished a program (German et al. 2012), about half regained more than 5% of their weight. Once your dog reaches its target, ask your vet for a maintenance amount and keep weighing monthly.

Exercise helps, food does the heavy lifting

AAHA notes that exercise plays a minimal role in weight loss compared with diet, and Cornell says activity makes enough difference only when combined with diet changes. Walking and swimming are gentle options that help keep muscle while the fat comes off. Build up slowly, especially in a heavy dog with sore joints.