Many people think weight loss is simply about cutting calories. They believe that to lose weight, you must reduce calories (either eat less or burn more). It would seem then that calories in, calories out is the only thing that matters and that to lose weight it should be as simple as eat less food, and if you stop losing weight eat even less and do more cardio. Although technically you will lose weight if you burn more calories than you consume, this is an extreme oversimplification of the process.
First of all, people don’t want to lose weight. “Losing weight” is the phrase we commonly use, but we really want to lose body fat and retain, or gain, muscle. The macronutrients (protein, fat, and carbs) you eat will affect whether the weight lost is fat or not. It’s not just about total calories.
Second, lowering the calories you consume (especially drastically/and or over a long period of time) will lower the number of calories your body naturally burns. Reducing your food intake will lower your body weight initially (usually anyways) but it’s not a simple matter of dropping them lower and lower as you lose weight. Your body isn’t a passive thing that you’re merely adding to and subtracting from. Instead, it’s a living, breathing dynamic system that responds to the lowered caloric intake by lowering its energy expenditure.
Finally, whole foods take more energy to digest than processed foods and they are more satiating (you will fuller for longer). Eating a meal with the same number of calories (even the same number of carbs, protein and fat) from meat, beans, veggies etc would burn more calories and lead to eating less calories later in the day than eating the same number of calories from pasta, grilled cheese, and a hot dog.
Focus on eating real foods and resist the urge to severely restrict calories to lose weight. Oftentimes your body needs more nutritious calories to lead to fat loss.