Our bodies are composed of primarily fat, muscle, water, bone and other tissue. All of these things combined make up our total weight. When someone says that they want to lose weight, they usually mean that they want to see a lower number on the scale. Thus, weight loss often comes from a combination of fat, muscle, and water to shift those pounds.
The prevailing formula for a long time on how much fat you’re going to burn was calories in minus calories out, based on your basal metabolic rate (BMR) and exercise efforts, explains strength and performance specialist Joel Seedman, Ph.D., owner of Advanced Human Performance in Atlanta. But with all the different biochemical reactions in the body, hormonal response, and endocrine function, there are an infinite number of factors that can affect how your body is storing and breaking down calories.