There's no such thing as a "fat-flushing" food, and there are no foods that can "flush" your body of excess fat. The only way to lose weight is to take in fewer calories than you burn on a daily basis, whether by changing your diet or by increasing your physical activity.
However, there are "fat-flushing" over-the-counter and prescription medications that bind to fat in your digestive system. These products can lead to unwanted side effects like uncontrollable diarrhea and nutrient malabsorption. They are generally not recommended as a healthy way to lose weight.
If you're interested in exploring this option, be sure to consult a healthcare professional first.
Keep in mind that you do not want to "flush fat" out of your body or reduce the absorption of fat in your digestive system. Fat is an important nutrient that's necessary for vitamin absorption, cellular function, and other functions in your body.