Reports suggest increasing numbers of Buddhist monks are contracting diet-related diseases such as diabetes because of fatty, sugary gifts.
Traditionally monks do not cook and depend on donations given by devotees.
The BBC's Charles Haviland in Colombo says on some occasions monks are given five-course meals.
Although most food given to monks is vegetarian, officials are worried that it is not always healthy, he adds.
"Because of their great affinity towards religious observances, most devotees offer food with high cholesterol content and the Buddhist monks have no choice but to partake of these foods all year round," Health Minister Maithripala Sirisena said, according to the Sri Lankan Daily Mirror.
"The situation is further aggravated because monks do not engage in recreational activities or exercises to shed their excessive weight."
He said the new menu was being drawn up on the instructions of medical experts and nutritionists.
They advise the monks to eat more fruit, vegetables and rice, to drink more water and to cut down on wheat-based foods.
The minister has also instructed health officials to open a ward exclusively for the clergy at all hospitals, the Daily Mirror reported.
However, prominent Buddhist monk Maadulaawe Sobitha dismissed the government initiative.
"For thousands of years, the tradition was for the devotees to offer food for the clergy. It was up to the monks to decide what is appropriate to consume," he told the BBC Sinhala Service.
"We have to be satisfied with whatever is given to us.  We are not supposed to demand anything.
"The main problem is that there are many monks in rural areas who have no nourishment at all. They survive on meagre rations of some rice and green leaves. It will be much more useful to initiate a system to ensure that these poor monks have a square meal a day, than just wasting resources for political gain."
Buddhist devotees in Sri Lanka who traditionally give food to monks are to be given special menus in an attempt to stop the clergy becoming sick.