● meat, fish, eggs, onion, garlic are strongly prohibited;
● grains (wheat, semolina, rice, oats, corn, rye, spelt, etc.);
● beans (dal (lentils), cacao (oil, beans, chocolate), peas, chickpeas);
● mustard seeds, sesame seeds (on Sat-tila Ekadasi, sesame [tila] seeds may be offered but still it is better to eat them on the next day);
● honey (is not considered a fully Ekadasi product because bees could have collected pollen from any plant);
● sea salt or any kind of sea product (seaweed, etc.);
● derivatives of these foods (wheat flour, mustard oil, soya bean oil etc.), and food items containing these products.
Examples of ‘safe’ products: ghee, fruits, buckwheat, potatoes, orange carrots, coconut, rock salt, common salt, sugar, and nuts.
Things that never break the fast (are permitted): medicine, milk, ghee, water (if it is not nirjala).
It is said, that on the day of Ekadasi it is better to eat at home (to avoid any accidental intake of particles of grains/beans) in a simple way. Of course, the only 100% safe option is to eat fruits.