Mobility and weight in the older pet: the lever with the best return

The link works in both directions and feeds itself. Excess weight increases the load on already painful joints, shortens the distance the animal can cover and sustains low grade inflammation; pain reduces movement, reduced movement costs muscle mass, and less muscle means less joint stability and more passive load on the structures. Breaking the loop at any single point produces improvement at the others too.

How powerful the lever is shows in a longitudinal study of a labrador colony followed for fourteen years: dogs fed a reduced ration compared with their littermates showed a median lifespan almost two years longer and later onset of radiographic signs of hip arthritis. This is not a miracle diet, it is evidence that body weight acts on joint function across a whole life.

Four measurements are needed, all of them doable at home. Three need only your hands and a tape measure, the fourth a scale. Repeated in the same way each time, they show within six weeks whether a change is working.

On the nine point scale ideal condition corresponds to scores of 4 and 5. Each point above 5 corresponds roughly to ten per cent above optimal weight, which lets you set a realistic target even without knowing the animal's historical weight. The difference in circumference between the two hind limbs is instead the most sensitive indicator of asymmetric use, that is, of pain the animal is compensating for.

Age related muscle loss with no disease to explain it is called sarcopenia, and it often goes with insufficient protein intake and reduced activity. Muscle loss that accompanies chronic disease, for example cardiac, renal or oncological, is called cachexia and is not corrected by adding calories alone. Telling the two apart changes the intervention completely.

• Muscle loss in an animal eating well, with normal test results and reduced activity: sarcopenia first, act on protein intake and exercise.
• Muscle loss with reduced appetite, a known chronic disease or abnormal values: manage it alongside the underlying disease, not with feeding alone.
• Asymmetric muscle loss concentrated on one limb: almost always indicates pain or a neurological problem on that side, and needs assessment.
• In older animals protein restriction is not a neutral choice: it should be decided by the vet based on the condition, because in many older individuals protein requirement does not fall at all.
• A lean, muscled animal is in better condition than a lean animal with no muscle, even when the number on the scale is identical.

1. 1

   Set the starting point

   Record weight, body condition score, muscle condition score and thigh circumference on the same day. Without a written starting point you cannot say whether the following weeks achieved anything.

2. 2

   Count everything that goes in

   For seven days write down the ration, treats, leftovers, morsels used to give medication and food given by other people in the household. In most cases the surprise is not the ration, it is the items nobody counts as food.

3. 3

   Set a target expressed as a percentage

   A sustainable reduction is around one to two per cent of body weight per week in dogs and 0.5 to one per cent in cats. Faster than that is not success, it is muscle loss.

4. 4

   Never fast a cat

   In cats an abrupt cut in intake or a few days without eating can trigger serious liver disease. Any weight reduction plan in a cat should be agreed with the vet and monitored against actual appetite.

5. 5

   Keep protein while reducing calories

   Cutting the total amount of a food also cuts protein intake and accelerates muscle loss. A food formulated for weight reduction keeps protein and lowers energy density: that is a different choice from simply giving less of the same kibble.

6. 6

   Recheck every two weeks and correct in small steps

   If nothing has changed in two weeks, reduce intake by about a tenth and recheck. Small frequent corrections work better than a drastic cut nobody can sustain.

The commonest mistake is not moving an older animal too little, it is moving it badly: little during the week and a lot at the weekend, always on the same ground, always at the same pace. An older animal with osteoarthritis tolerates regular distributed load well and tolerates peaks badly. The practical rule is to favour frequency over duration.

• Several short outings a day instead of one long one, keeping the same total distance.
• Even, non slippery ground, avoiding steep descents, which load the front limbs, and running with sharp changes of direction.
• A few minutes of slow walking as a warm up before increasing pace, and the same at the end.
• Controlled loading exercises prescribed by the vet or physiotherapist: stepping over low obstacles, walking up a gentle slope, standing on unstable surfaces.
• For cats, ground level play in very short repeated sessions with targets that stay low: what needs reducing is jumping from height, not movement itself.
• The day after any new activity, check for lameness, stiffness or difficulty rising: that is the test that tells you whether the load was right.

Much of the independence an older animal loses comes not from the joint but from the environment. A slippery floor stops an animal getting up even when it has the strength to do so, and a high rim makes inaccessible a litter tray the cat would gladly use. These are almost zero cost changes with an immediate, measurable effect.

• Continuous non slip routes between resting places, bowls and the door: an isolated rug does not help, an uninterrupted surface does.
• Short nails and hair between the pads kept trimmed: two details that restore grip and reduce slipping.
• Bowls raised to chest height for animals with neck pain or difficulty holding a lowered position.
• Stable ramps instead of jumps onto the sofa and into the car, introduced calmly before they become essential.
• A litter tray with one lowered side, placed on the floor the cat actually lives on: many cases of a senior cat toileting outside the tray are an access problem, not a behavioural one.
• A bed with enough support to avoid contact with a hard floor, in a draught free spot reachable without stairs.

Impressions of wellbeing change with the mood of the person looking. You need concrete indicators, taken the same way each time, that let you compare today with six weeks ago. Three are enough, as long as they are recorded with a date beside them.

If after six weeks weight has fallen but the functional indicators have not improved, weight was not the only problem and the analgesic part of the plan needs reviewing with your vet. If instead the indicators improve before the weight does, the environmental changes and the distributed load were already doing their job, and it is worth consolidating them.