Exactly my point, so what do you conclude from that?
Natural diet would there for be based on meat and in season local fruits and vegetables. Humans never ate apples and oranges and bananas and avocados all year round 365 days a year. There in lies the problem. Meat in one form or another however is available year round almost anywhere on this planet.
This is the exact reason why humans and any animal cared for by humans are the only creatures on this planed that get past their optimal weight. A dog being fed it's natural diet and exercised will not get fat, a dog fed up on man made foods and fed three meals a day usually ends up over weight and unhealthy.
Humans never ate three meals a day, these days people are projecting these ideas (three meals a day plus snacks) onto animals making them unhealthy.