Not true in my case. I can eat a very good diet of homemade food, with lots of veggies, and stay fat. Interestingly, I have two small dogs. Every day I measure their food. They eat the exact same diet. One is very thin. One is a chub! The chubby dog is far more active than the thin dog, too. He ought to be thinner, but he can’t lose weight. (I don’t think he particularly cares.)