Yogi Iyengar was born in 1918 - so in another 10 years time, God willing, the body may reach 100!
" The fact that people are focusing on the size of his belly and deeming it unattractive only means they have a limited understanding of yoga and it's purposes. one of the reasons his chest, because it's not really his belly but his entire upper body including his back, is so large is because of pranayama. he has a whole book on the subject entitled "light on pranayama". also, a strong body does not necessarily mean a thin or muscular body. " Just copied what someone else wrote - found it very interesting and may help to answer your question?
Namaste and salaams!