Eat more high-fiber, low-starch carbs.
High-fiber, low-starch carbohydrates are some of your best friends when it comes to fighting belly fat. Simply increasing your intake of non-starchy vegetables and fresh fruits is a GREAT way to fill you up, suppress hunger, avoid food cravings, and cleanse your body naturally. Avoiding starchy carbs also helps to keep your blood sugar and insulin levels stable.
Eat some lean protein every 2-4 hours.
Lean protein is another great ally when you want to lose weight fast and burn belly fat quickly. It's a "hot burning" food that speeds up the metabolism while also keeping hunger in check. Most importantly, it stabilizes blood sugar, insulin, and energy levels... which all translates into less abdominal fat. Eat a small amount of lean protein every 2-4 hours and you'll have more energy and a smaller appetite.
Avoid all highly-processed carbs.
Eating highly-processed/refined carbohydrates gives you more belly fat and makes it almost impossible to lose the tummy fat you already have. Refined "white" sugars and flours are the worst culprits because they spike your blood sugar and insulin levels. Empty "sugar" calories plus high insulin levels = more belly fat. Focus on natural, unprocessed foods and lightly processed foods, especially veggies, fruits, beans, legumes, oatmeal, sweet potatoes, and whole grains.
Eat plenty of healthy fats.
Not all fats make you fat. Some can actually speed up the weight loss process. For best results, you need to avoid trans fats and most saturated fats as much as possible, especially like those found in fried foods. Eat more monounsaturated fats and essential fatty acids (e.g. omega 3 fats). Examples: virgin olive oil, nuts and seeds, avocado, and oily fish.
Do interval-based exercise.
The best form of exercise to lose belly fat fast is interval-based exercise. High-intensity interval training is one great example. Full-body circuit training based around bodyweight strength movements (e.g. pushups, pullups, squats, burpees, etc.) is another. Performing intervals burns lots of calories and burn off extra abdominal fat faster than just about anything else. Plus, interval exercise causes the body to produce powerful fat-burning, muscle-sparing hormones that make it much easier to lose weight fast!