In the hunger games what did the citizens eat to survive?

If you're talking about citizens of the Capitol, they ate delectable meals while the others in the districts nearly starved, having to hunt for their own food and grow their own crops. When Katniss was getting used to her new life style there, her favorite of the Capitol delicacies are lamb stew with dried plums. She also enjoyed eggs and toast with hot chocolate.

Most of the snobby citizens there feasted on roasted cows, pigs, and goats, fruits and nuts, crustaceans and fish, cheeses, soups, breads, eggs, ham, fried potatoes, fruit, and orange juice is a hearty breakfast. Chicken and mandarin oranges in a thick broth with grain would be a simple lunch, paired with peas, onions, warm rolls, and scrumptious pudding for dessert. For dinner, one may eat mushroom chowder with greens, roast beef, noodles swimming in green broth, cheese that is served warm with blue grapes, and an absolutely prime cake for dessert. Dinner would be usually served with wine and optional water. Small hard candies are eaten throughout the day. Wine and spirits (alcohol) were also readily available during a grand banquet in the victory tour as seen in pages 77 to 79 in Catching Fire. They even drink alcohol to force them to throw up in the Capitol so they can eat even more!

Octavia, Katniss's stylist is the only Capitol person described to be plump. The rest are experts on purging, and technically are adapted to bulimia nervosa (an eating disorder in which people eat everything in sight then vomit it out of their bodies to keep thin).