"A lot of onions in the cooking we try and reduce, because you know, it doesn't give you good breath," the summit's executive chef Jess Ong told AFP in an interview.
Garlic is on the blacklist to make sure the Asian-inspired dishes do not foul the air when the 21 leaders from the Asia-Pacific Economic Cooperation (APEC) forum converse.
US President Barack Obama, Chinese President Hu Jintao and Russia's Dmitry Medvedev are among the summit participants, although Obama's schedule remains in flux and whether he will break bread with the others remains in question.
Preparing meals for APEC leaders is always daunting for host countries because the members represent hugely diverse food traditions in Asia and the Americas, stretching from China to Chile via Papua New Guinea.
"It's not a culinary adventure. They have a meeting, they want to recognise the food that they will eat, they do not want to look at the food and say 'I'm not sure I can down this dish'," said Ong, 51.
Onions and garlic aside, the chilli content of local delicacies served at the summit will also be toned down, and the guests can choose between cutlery and chopsticks.
But there will be no compromise on the essential flavour of the dishes, insists Ong, a 30-year industry veteran whose clientele has included the late Princess Diana.
"The element of our local specialities is delivered in a different format.
"This is a variation, rather than heavy, sweet, spicy, hot. So it becomes infused with olive oil, chilli, lemon grass, but very subtle integration."
The leaders' menu this weekend cannot be disclosed in advance, said Ong, who is executive head chef at the main APEC venue, the Singapore International Convention and Exhibition Centre.
Luncheon and a banquet dinner are scheduled for Saturday. Obama will still be en route from a visit to Tokyo, and his only APEC repast could end up being lunch at Singapore's Istana presidential palace on Sunday.
A four-course lunch for APEC ministers last Wednesday featured seared barramundi fish with ginger scallops, mushroom dumpling, wilted water spinach, hot and sour coulis, radishes, baby carrots and asparagus.
Ong did drop a hint of what might be in store for the leaders.
For health-conscious Obama, Ong recommends the local delicacy "yu sheng" -- a colourful salad consisting of raw fish slices, thinly cut vegetables, sweet-and-sour sauces and strips of crackers.
"It's clean, it's healthy, it's tangy, it's about as Singaporean as you can be," he said of the dish, which is traditionally served during Lunar New Year parties and was created by Chinese immigrants in Singapore. (AFP)