To lose belly fat quickly, it is important to eat a balanced diet that is low in saturated fats and sugars and high in lean proteins, complex carbohydrates, and healthy fats. It is also important to reduce calorie intake, as well as increase physical activity. Additionally, it is important to drink plenty of water and get adequate sleep. Some foods that can help you lose belly fat include avocados, nuts, eggs, salmon, and leafy greens.