Yes, it can. If your turtle or tortoise cannot fit all of its body into its shell, this is a sign that it might be overweight. According to veterinarians, if this happens, you will need to reduce the food they consume to 30 or 40% of its original intake for a few days. You should not worry. Your turtle will not get too hungry because its body will begin to consume its body fat reserves.
Another sign of obesity is if the head of your pet is extremely wide compared to the rest of its body. In addition to limiting the food intake of your turtle or tortoise, you can give your pet a little bit of exercise. If it is an aquatic turtle, you can put more water in its tank so that it can move around more, or you can set up a little room for your land tortoise to run around and play.