MyFitnessPal is one of the most widely used calorie tracking apps. You log what you eat, and the app calculates calories, macronutrients, and other nutritional information based on a large food Database. You can also log exercise, water intake, and weight. The idea is that tracking what you eat makes you more aware of your habits and helps you make adjustments toward a goal, whether that's losing, gaining, or maintaining weight.

The free version covers the basics, and the premium tier adds things like meal planning, nutrient breakdowns, and no ads. The app syncs with many fitness trackers and smartwatches, so exercise data can flow in automatically. The database is crowd-sourced, so accuracy varies, and weighing your food is more precise than estimating. Still, for anyone who wants a straightforward way to understand their eating patterns, it's a practical tool that has been around long enough to be reliable.