What is a Caloric Deficit and how does it relate to weight loss?
To lose weight you have to be in a caloric deficit. To be in a caloric deficit (calorie deficit) you need to eat fewer calories than you burn each day. Your body naturally burns calories all day, this is called your basal metabolic rate (BMR). Your BMR represents the calories you burn from preforming daily functions such as breathing, digesting, sleeping, circulating, thinking and more.
Here is a calculator to find your estimated BMR
Along with your BMR you also burn calories when exercising. Daily exercise like walking , dancing, yoga or weight lifting are great way to help you reach your caloric deficit. Furthermore, exercises like weight lifting will help you build muscle. The more muscle you have, the higher your BMR will be since muscle take your body more energy to maintain.
You can use this calculator to find your maintenance calories. Maintenance calories is the amount you need to eat each day to stay the same weight. This will help you get a better understanding of the amount of calories you burn each day through your exercise and BMR.
Above is an example of a calorie deficit. In this example the subjects BMR + calories burned through exercise is 2,549. To stay the same weight they will need to eat 2,549 calories. To lose weight they need to eat less calories than what they burn daily, creating a calorie deficit. When you create a calorie deficit, your body gets energy or fuel from stored fat. This is how weight loss accurse.
So as long as you consume less calories then the calories you burn though your BMR and exercise you will be in a caloric deficit. Since you are burning more calories than you are taking in you will lose weight.