What is a realistic timeline to help a large dog lose 5kg?

For a 40kg dog aiming for 5kg loss, 1.5 percent of the current 40kg is 600g a week, which would suggest roughly eight to nine weeks if the rate stayed completely constant, though in practice the rate slows somewhat as weight and the corresponding percentage based target decrease.

A more realistic expectation, accounting for this natural slowing, is closer to two to four months for a 5kg loss on a large breed dog.

How consistently the reduced food amount and any exercise plan are followed makes a real difference, and occasional lapses, such as a holiday period or a change in routine, can extend the overall timeline without being a failure of the plan itself.

Starting body condition also matters, since a dog with more weight to lose sometimes loses the first portion a little faster before the rate naturally slows closer to target weight.

Weigh every two weeks and track progress against the overall goal, recognizing that a multi month plan is normal and expected for a meaningful amount of weight loss, not a sign of a plan going wrong.

Celebrate progress at reasonable milestones, such as each kilogram lost, rather than focusing only on the final target weight, which can feel distant for the first few weeks. A visible record, such as a simple chart kept on the fridge, helps make gradual progress feel tangible over what is otherwise a fairly long, slow process to see through to the end.