Is a dad bod the same as being overweight?
Not always. Some men look soft and sit at a healthy weight. Some are heavier and strong. The useful measure is your waist. See is a dad bod unhealthy.
Why is it called a dad bod?
Because it tends to arrive with kids, a bigger job and a full calendar, the years when training, sleep and food get the least attention.
Can I change it?
Yes. Four habits do most of the work. See How to lose a dad bod.