Obesity in dogs and cats: a vet's honest guide to weight loss

The kindest thing I can say in a consultation is sometimes the hardest: your pet is overweight, and it is shortening their life. Obesity increases the risk of arthritis, diabetes, urinary disease, breathing problems and some cancers, and studies show lean dogs live around two years longer than their overweight littermates. The good news is that unlike most diseases, this one is completely reversible.

First, check honestly. Feel the ribs — you should feel them easily under a thin fat cover, without pressing. Look from above for a waist, and from the side for a tummy tuck. If you're unsure, ask at your next visit; we score body condition at every examination.

Weight loss is arithmetic plus patience. Calories in must drop below calories out, and the safe rate is 1–2% of body weight per week for dogs and 0.5–1% for cats. Faster is not better — rapid weight loss in cats can trigger hepatic lipidosis, a dangerous liver condition.

The practical plan: measure food with a scale, not a scoop or an eye. Feed the calculated amount for your pet's target weight, not their current weight. Cut treats to under 10% of daily calories — and count dental chews, table scraps and the children's dropped food as treats. For cats, puzzle feeders slow eating and add activity; for dogs, replace half the walk-and-treat habit with walk-and-play.

Weigh every two weeks, same scale, same time of day, and write it down. If there is no loss after four weeks, the plan needs adjusting — usually the hidden calories are somewhere. This is genuinely easier with veterinary support: prescription weight-loss diets keep protein high and hunger manageable in a way that simply feeding less of the old food does not.

If your pet is overweight despite honest portion control and exercise, mention it — hypothyroidism in dogs can drive weight gain and is easily tested for. Use the Diet Calculator on this site for a starting calorie target, then bring your pet in so we can tailor it.