It is the same as if we were dieting. You can eat the same foods, just a smaller amount and you still get the nutrients, but not all of the calories. It is what your dr would recommend for you. I do agree with Doc that you should keep a dog on the same food. We did switch food with our dog, but she is still on it. It has a lower caloric value, but has extra vitamins and minerals that she needs. We will switch her back, but it will be gradually.