Terry really does have awesome abs, but the underwater camera adds 10-15 pounds, thus distorting his six-pack.
I also think that Terry enjoys life to the fullest. This might include consuming foods other than nuts, fruits, or vegetables. There is also the law of gravity which is more profound among those of us in our 60's.
Terry is incredibly fit with more energy than most people half his age. I like his middle age build because it gives the "everyman" image letting us old guys know that a high level of fitness is still attainable.