A well-known monk with a bodily disorder was the deceased Bhikkhu Buddhadasa, who was given all kinds of diets when he was alive. Buddhadasa was fat most of his life.

However, some current Western monks (based in Western Australia) have put on lots of weight, which looks like eating too much rich food & doing too little exercise. 

You reach an age when you start to put on lots of weight. You must reduce your food intake because your body obviously does not need so much food anymore.

Two years ago, I cut my food in-take in half & stopped eating certain foods (cheese, ice-cream, bread; I never ate much sugar). I lost 12kg but notice if I eat certain prohibited foods (such as when visiting my mother, I add weight quickly). 

These monks are often given lots of Asian sweets & cakes and drink lots of sugar.