This post is part of the World Building Blogfest. Click on the logo to find other participants.
As a purely practical matter, food is very important to R’il’noids using their esper talents. These talents are not used without effort. In particular, the laws of conservation of energy, conservation of momentum, and conservation of angular momentum apply to levitation, telekinesis, and teleportation. Although much can be accomplished by counterweighting (moving an external mass in such a way that the net change in energy, momentum and angular momentum are zero) the energy required for esper work is considerable and R’il’noids and the R’il’nai are notorious for always being hungry. This is particularly true of Healing, where the energy used cannot be offset by counterweighting. The rule is “carbohydrates before intense esper work; protein after.” Failure to comply can lead to hypoglycemia (insulin shock) and loss of consciousness. Espers normally carry tubes of honey.
Physical meetings of the Inner Council are always accompanied by high-calorie finger food. Tastes vary, but the food usually has plenty of sugar or honey, often combined with fruit, cream and pastry. After a meeting, some kind of rich soup is in order.
Most food preparation is automated, but there are restaurants with human-prepared food, and experts who develop new dishes and the programs to prepare them.
Individual planets vary greatly in their cuisine and the ingredients available. Marna on Riya lived mostly on wild fruit and nuts, fish, and the produce of her garden. Several of those plants (tika berries, haro nuts, pala fruit, frostberries) were later introduced to Central. Falaron (Terraformed form Earth during the Pleistocene) offered auroch steak and roast peccary. Ethnic restaurants from all over the Confederation abound on Central, while the people of Eversummer, where all imported animals died off very early and the native animals are toxic, live mostly on yams, legumes, cassava, fruits, nuts and grains. (They also eat their dead as a religious rite, and Marna suspects that this developed partly because their diet lacks complete proteins.)
Non-alcoholic beverages include a wide variety of fruit juices and herbal infusions, some with considerable caffeine. (This includes what we would call coffee and tea, both imported from Earth.) Chocolate was imported from Earth quite early, and is used in a variety of beverages. (I know, chocolate is not native to Africa, but the people who followed Jarn found possible food plants on a number of continents.) Milk and cream from a variety of mammals is used in beverages as well as sweets. Of course water is drunk almost everywhere, though in some places (such as Eversummer) pretreatment is needed.
Alcoholic beverages are even more varied. Just about anything with carbohydrates can be used to make an alcoholic beverage, and is on some planet or other. Wine from grapes is probably the most popular among the R’il’noids, and here a peculiarity of their metabolism must be mentioned.
Most R’il’noids have an enzyme in their saliva that breaks down alcohol even before it can be swallowed. Alcohol taken by mouth literally cannot intoxicate them, though most enjoy the complex flavors and aromas of fine wine. In fact, alcohol serves as an excellent fast energy source.
At the opposite extreme some ethnic groups completely lack the ability to metabolize alcohol. One such is the Clan, a starship-based culture spending their entire lives on starships, and making a living by trade. Clan members are notorious for having no head for drink, and can become addicted to alcohol very easily. I have one character from this group, and his taste for alcohol is part of the plot of Tourist Trap.