It's more of an Internet slang than an idiom. In 2020 there was a grass-root influencer called 诗书达礼之山人 on Douyin(the original Chinese version of TikTok) uploading a few video clips, and at the start of each video he shouted in Sichuan and Chongqing dialects "干饭了干饭了((let's)dig in; (let's)dig in. 干, means to eat rather than the adjective "dry", smacking of eating up, or bottom up as in 干杯; 饭, means rice)", holding a bowl of rice covered with several slices of meat and vegetables, squatting down and waiting for a chicken to peck his meal before he stuck out his leg and tried to sweep down the thief. Later the slang began to take hold among many youngsters and developed the meaning of "what I strive for is to have a meal". 干饭人 refers to the person who is enthusiastic about eating food, but not to the level of gluttony, nor a foodie. I can't think of an English equivalent of this slang. So I would just use "gan fan people" and explain a little.