I don’t know about labs, but my golden is a furry goldfish.
Our Golden is huge. We had increased his exercise and cut back on his food until he was on half rations of diet food but he was still gaining. Vet checked his thyroid and he is now on meds, which are helping him lose. Older Goldens are prone to thyroid issues as they age she told us.
They are wonderful dogs, happy and playful even when older. He is a good watch dog too. He sleeps in front of the front door at night and let’s us know if a cat comes on the front porch. lol