Unless the people in your world do not eat or consume energy in any form, all cultures have food or drink customs surrounding food items, morals, ethics on killing or harvesting, historical importance, religious limitations, laws, or social conformity to what is eaten, how food is consumed, and why food or the drink exists.
Even if in your world, the inhabitants do not physically chew the food, absorbing energy by any means is a form of ingesting. So maybe in your world the main food source is a stone that releases a type of energy that is absorbed by those in your world. Maybe the substance goes straight through to the stomach bypassing any mouth. Both are forms of eating.
Take a look at your world and think along food and drink lines. Where does the food come from? How is it prepared? Are their special foods?
What is your favorite food and why? Use that as a base for your world, would the character like what you like or be appalled at your diet?
Think also on expanding or even limiting the senses. Maybe in your world a person can see what they taste, as in the odor? Maybe they can taste the color of the food? How would red taste different than say blue? What if your world had no taste receptacles for heat/spiciness or sweetness: how would that affect what they eat or how they perceive another culture that can?
Sources of food
Generally food comes from one of three types of main sources: farming/ranching, hunting/fishing, or gathering/foraging. Deepening on your world one or all three may be employed.
What percentage of your food is farm produced? Are these big farms or small farms? Does the amount of produced harvested fit the needs of the population? What about gleaners, is that practiced used and if so again why? Does the biome yield to food produce? If not what special technology or magic is employed to assure an harvest?
Hunting, is it allowed and if so what animals are protected if any from the hunt? Is there a ritual done before killing an animal; either domesticated or wild? Is all the animal used or just a percentage? If so what is the justification of that act?
Is all food shared communally, sold/bartered by individuals, or is the food rationed out by a government/religious official? If so are the rations equal? If unequal what is the basis for calculating who will get what?
Then you need to decide what level of technology is incorporated into your food production. Are their high production farms that yield record crops on scant small land usage based on scientific formulas and chemicals? Or do your inhabitants prefer to let nature take the rein even if the yields are poor.
What of the religious or ethics are involved in the planting or harvesting of food? Does your world have strict kill policies or anything is game to eat? What of religious diet, are there any food that are forbidden to your inhabitants? Is there specific ways a food must be harvested from the fields?
So what does YOUR world say about food or drink? How does the “culinary world” define your world?
Food and Society
Are there any restaurants, cafes, drive up window idea? As eating establishments frowned upon? Is the idea of family dinners preferred?
What about single diners? Are single eaters allowed in food establishments? Or are such places only for single eaters and not groups?
Is there any talking allowed while eating? Drinking? What about utensils are there any main in etiquette rules? For example what fork to use or how to place those chopsticks.
If you have more than one culture on your world, how does food show the difference between the two cultures? Does the food cause any problems between the different cultures?
If you have more than one main culture on your world, do you address the differences in food preferences? Is there a stereotypical dish that represents the culture and everyone eats it no matter what?
Another idea one must take into account is can the reader identify with the food item you are mentioning? For example, would the reader be able to smell the bread cooking even if the bread is alien to the eyes. The common thread is that bread is common and thus have point of reference with your character.
Or would the reader take offense or felt nauseated with what your characters are eating? Maybe that is the goal to shock out the reader. Strong emotions that can be elicited can help or sink a story.
Over the years or time period, can palates or popularity of food change? Is the food now the same as it was 20, 50, 100, 1000 years ago in your world? If food has changed why? No longer available? Mood set of the populace has changed? The food no longer taste the same? No one eats (blank) because it has become associated with death?
So you have different level of classes in your society? If so does that show in their food habits? Does everyone eat the same basic food items despite how rich or poor they are? Are only certain items deemed for the top percentage of the society or even bottom?
Hunger, does that exist on your world? Are inhabitants dying from lack of food? What is your culture doing if this is a concern? Is there a reasoning for the hunger? War? Ecological? Overpopulation? Greed? Environmental?
One more thing to consider: are there any eating disorders? Is there a reason someone may eat little or a lot? Is the impact negative or positive? Is there solutions? Does your society shun anyone who participates in such or praise them?
Is there one main gender that does all the cooking? Is there the role split between genders? If a career is it considered useful, productive, high skill or low skilled?
How is food prepared in your world? Special rituals for all meals?
What kind of cooking equipment is used? Regular run of the mill, robots, specialty items? Is some equipment only used at certain times of the year depending on seasons or holidays?
Is there any hand preparation or is all the food already done when purchased?
Is there any training in your culture to cook?
What type of devices are used for the cooking of the food? High technology machines, microwaves only, fire pits, regular ovens? Magic?
Does your culture have recipes? Family generated ones? Is there anything that can spoil a recipe? Why are certain dishes popular? Is there a version of fast food? Junk food? Comfort food?
Are certain smells inciting, like bacon? Or is the smell of food cooking offensive to a culture?
What about super-foods? Highly nutrient foods, yummy or gross tasting? What about foods that have an effect on the body, from emery inducing, hallucinogenic/ mood altering, to curative properties? Maybe certain food give the user properties that could be considered paranormal or superpowers?
Now that the food is ready to eat….
How and where does one eat? Does your inhabitants eat with a mouth and teeth to chew, gnash? Or is there a unique way to eat? Maybe a sucker type mouth etc. The physical act of eating will determine a lot about what your culture eats and why.
So let us for now go with tradition chewing and swallowing. Where does one eat? Standing up, while walking, on the computer, or in a vehicle?
If a table involved, is there a specific way in which it is set? Any rituals involved? Difference for holidays and regular days? What kind of plates and utensils are used? Plastic, china, pottery, metal? Is there any ban on certain plates etc. or the way they are used or disposed of?
Communal style dishes with a pass the dish idea? Does one person put food on a plate for each member of the table? Does one person do the carving of meat or dishing? Separate dishes for separate foods? Is there a hierarchy in how you receive your food?
If one person stops eating do all?
When are the children feed, separately or with the rest?
Mind your P’s and Q’s
What is the etiquette applied to food and drink? All cultures have some form of etiquette in connection with food, so what are yours?
Maybe in your culture making the most noise possible will show appreciation for the food? Maybe silence shows the same idea in another culture? If the two eat together what could one expect: tolerance and understanding or offensive and anger?
Are there servants? How are they treated? How does the diner treat the servants?
Any napkins or toothpicks? Or does one just use the sleeve and a knife point to pick the teeth?
Are there different etiquette practices for class, business, and religious strata? What happens of your cross that strata when not a member? What happens if you violate etiquette customs? Any specific manners that must be adhered to?
If you have a religion in your story, how does that play into food? Nothing in particular? What you may or may not eat regulated? If so what is the reasoning, superstition, tradition, or a sacred text said so therefore?
What is forbidden by law, social morals, or religious views?
Is there any prayers, sacraments, or ceremonies that accompany food?
Does the government or religion have a say in what a person may or may not eat? How much they can eat? Or even when they are allowed to eat?
Spices, Condiments, oh my!!!
As a culture, do your inhabitants prefer sweet foods, savory, society, or bland foods? Are spices an integral part of the economy let alone the food? What types of spices are used regularly? Any reasoning as to why?
Is spice being used to as a preservative like salt? Is spice used as a marinade?
Is there any condiments that your culture absolutely needs, like ketchup/catsup? Does your culture frown upon a condiment used on certain foods?
Is your character ‘lost’ if he/she/it cannot have needed item with their food?
So your character is finished eating: what now????
What happens after a meal?
If a guest how does one thank the host of the party/gathering where food or drink was served? Is there any specific rites or rituals that must be followed? Does you culture expect long drawn out thanks-you and accolades or just a quick bye? Maybe your culture does not speak but sends out thanks by way of written word or a gift?
How does one pay for food at a restaurant etc.? Is it paid upfront, afterwards? Is cash used or do you do the dishes for the food idea?
Drinks, drinking songs, or just fish tales to entertain.
Drinking a liquid is needed by most lifeforms, though there are always exceptions to the rules. So let’s say in your world the inhabitants need fluids to survive. More than likely that would be water, however it does not need be. It can be any fluid, even alcoholic if your species had evolved to avoid the obvious effects on the physical body or actions.
Do you have taverns, bar, clubs, or drinking establishments? What kind of libations are carried in these establishments? Strong drink, nonalcoholic, natural teas, or maybe magic elixirs.
Is there a minimal age to be in those drinking establishments? Why? Are all genders/races allowed, or only one section?
Do the drinking establishment gear themselves to average friendly citizen, rough crowd, looking for illegal activity, or just wanting love in all the ‘right’ places?
Any religious objections or encouragement to an alcoholic drink? What about accidental alcohol intake like a fermented cider or fruit?
Are people happy when they drink, especially if alcohol affects the body or is the mean drunk more common in your world?
How are beverages made: huge corporations, small businesses, or combo? How are beverages marketed?
Best part of any meal: Desserts
What kind of candy/desserts do people eat in your world? Is sugar or honey even known? Any artificial sugar? Is it banned? If a rare commodity what links will one go to gain a sweetening agent?
Are sugar item frowned upon? Only for holidays? Only for certain career levels or as rewards for socialistic behavior?
Odds and ends to think about:
In your world is there one meal that is significant for either religious (think communion or last supper motif), a wedding that failed miserably, eating for the dead rituals, or even a ‘come to dinner for malicious intentions’ (loosely Medea in Golden Fleece idea).
Superstitions about eating, like throwing salt over left shoulder (to reverse a bad omen) or picking up bread that has fallen and kissing it before tossing it (the idea there is bread is the staple of life)
Any famous chefs or cooks? What have they done to achieve such success? Are they a one name off character or have a depth that can add to the plot?
Are there food bans? Taxes? Rationing? Food banks? Communal gardens?
Are people allowed to have gardens or raised their own farm animals? Is the practice restricted? If so, what is the reasoning there are restrictions?
In the evolutionary record of your world, is there any particular food or drink that would be detrimental or cause discomfort among any of the inhabitants/races?
How does your world store the food? Are there freezers? Ice caves? Root cellars? Jars or pottery? Any kind of refrigeration at all? Certain foods need to be cold to work, simple example gelatin or ice cream. If there is limited refrigeration then if there is a cold spell in the seasons, are these kinds of food popular?
Last but not least: is poison an issue in your world? Do you have testers? Special equipment to scan for poison? Can all poisons be detected? Can some slip pass the technology of the land?
Some videos I found online that may be of help to you
World Building: Fantasy Food and Rations
World Building – Food
Food in Novels | World Building Help
World building: Food
A Beast Requires: World Building Through Food
Worldbuilding Wednesday, episode 1: Metal and Food
Lore and world building: food
Dive into Worldbuilding: Food!
Forager Forge | The Civilised Neighbours
Bird Island | The Food Web (not in English but captioned)
Bird Island | The Rainforest Buffet (not in English but captioned)