Go what the vet that has examined them recommends. I would give no snacks except raw carrots (1/4) to chew on once or twice a day. Add water to their kibble. In fact, if you presoak it, it puffs up and they think they are getting more.
I would find a way to increase their activity, more walks around the block, even if leisurely and only for a few minutes at a time.
Swimming is the best activity for burning calories and it’s easy on the joints for seniors.
By any chance, do you have pet health insurance? I ask, because I have heard that if the vet orders aqua therapy (swimming in a heated pool, offered at pet rehab facilities) for weight loss or a medical condition it may be covered. One minute of swimming equals 4 minutes of running.
