An older cat's stomach reads a sudden food change as a threat, so the senior food transition is won by pace rather than by the bag on the shelf: small steps, one variable at a time, and close attention to what her digestion reports back.
The Week-Long Mix
Begin with a small amount of the new senior food mixed into the old, and increase the new share every couple of days over at least a week — longer if her stools soften or her enthusiasm dips. Watch three things as you go: her stools, her appetite, and whether she still arrives for meals with interest. A day of slightly softer stools at a new ratio usually means hold that ratio for another day or two, not abandon the change. Keep mealtimes, bowls and feeding places exactly as they were, so the food is the only new variable and any reaction has one obvious suspect. Serve the mixture fresh at each meal rather than leaving a blended bowl down all day, since the point is a measured ration she eats with appetite, not grazing.
Choose for Her Condition, Not Her Birthday
‘Senior’ is a life stage, not a diagnosis. A lean, active older cat and an overweight one need different things from the bag, and standard, weight-conscious and kidney-conscious options exist because older cats diverge. Choose for the cat in front of you — her weight, her muscle, what her last check-up found — and let a vet who knows her help pick if you are between options. Weigh her monthly through the change, because slow, unintended weight loss in an older cat is information, not a bonus.
When to Pause and Get Her Checked
An older cat who loses interest in food during a transition, refuses the new mix outright for more than a day, or loses weight the plan did not intend should be checked rather than coaxed indefinitely. Appetite loss in a senior cat is a symptom with many possible causes, and the transition is a common moment for an unrelated problem to surface. Your vet would rather hear about a stalled changeover early than meet a cat who has been eating poorly for weeks. Where several people feed her, agree who serves which meal and at what ratio, so the mix climbs steadily instead of resetting whenever a different hand fills the bowl. Care Teams earns its place in KinsLe during a transition like this one: the morning feeder records the day's mix as a finished, timestamped duty, so the evening feeder continues the same ratio instead of guessing where the changeover stands.