Obesity is an excess of body fat caused by taking in more energy than the animal burns. Vets assess it with the body condition score: if you cannot easily feel the ribs and cannot see a waist from above, your pet is carrying too much. It raises the risk of arthritis, heart and respiratory disease and anaesthetic complications — and it shortens life expectancy.
Key facts:
- What it is: excess body fat — more energy eaten than spent.
- How it is assessed: the body condition score (BCS).
- Warning sign: you cannot easily feel the ribs, and there is no waist from above.
- Risks: arthritis, heart and lung disease, diabetes, and greater anaesthetic risk.
- Contributing factors: breed, age, neutering — and, above all, the owner’s habits.
- Losing weight: a vet-prescribed diet plus gradually increased exercise.
Obesity is the commonest nutritional disorder in pets, and almost the only one entirely within the owner’s control. It is also the one owners find hardest to see, because the change is gradual and because a fat pet still looks like a happy pet.
What causes obesity?
At bottom, one thing: more energy going in than going out. But several factors make that easier to fall into. Neutering lowers energy requirements, so a pet fed the same amount after the operation will gain weight. Age reduces activity. Some breeds are predisposed — Labradors famously so. And then there are the owner’s habits: treats, table scraps, an extra scoop “because he looks hungry”, and several family members feeding the same animal without telling each other.
How do I know if my pet is overweight?
Vets use the body condition score (BCS), and you can do a simplified version at home. Run your hands along the flanks: you should be able to feel the ribs easily, under a thin covering of fat, without pressing. Look at your pet from above: there should be a visible waist behind the ribs. Look at it from the side: the belly should tuck up, not hang level or sag. If the ribs are hard to find and the outline is straight, your pet is overweight.
Why does it matter so much?
Because fat is not inert padding — it is an active tissue that causes inflammation, and the extra load damages the body mechanically. Overweight pets suffer more arthritis (every extra kilo is carried by the same joints), more heart and respiratory disease, more diabetes — particularly cats — and they face a higher anaesthetic risk if they ever need surgery. The blunt summary is that obesity shortens life expectancy and reduces the quality of the years that remain.
How does a pet lose weight safely?
Not by simply cutting the ration of its normal food — that risks leaving it short of protein and micronutrients while still hungry. The proper route is a vet-prescribed weight-loss diet, which is formulated to be lower in calories but complete, combined with a gradual increase in exercise appropriate to the animal’s current fitness and joints. Weight comes off slowly, and it should: rapid weight loss in cats in particular is dangerous.
The hardest part is the household
Weight-loss plans fail for a very human reason: someone keeps feeding the pet. If one person is measuring the ration while another slips it sausage under the table, nothing works. Everyone has to agree, treats have to be counted as part of the daily allowance, and the animal has to be weighed regularly so you can see whether the plan is actually working.
Frequently asked questions
How do I know if my dog is overweight?
You should be able to feel the ribs easily and see a waist from above. If you cannot, it is overweight.
Does neutering make pets fat?
It lowers energy needs. If the food is not adjusted afterwards, the pet gains weight — the surgery itself is not the culprit.
Can I just feed less of the normal food?
That risks nutritional deficiencies. A vet-prescribed weight-loss diet is complete but lower in calories.
Does obesity really shorten life?
Yes — and it brings arthritis, diabetes and heart disease with it along the way.
Arthritis, diabetes and heart disease are long, costly conditions — and once they appear they count as pre-existing. Petplan España (Petplan Ibérica, S.L.) reimburses 100% of the vet bill up to €3,100 a year, with a €45 excess, at any vet you choose. See the policy terms.
