Firstly, as the subject implies this article relates to fat loss not weight loss. The preservation of lean body mass (LMB) is vital to ensure as minimal loss in total daily energy expenditure (TDEE) as possible. There will always be an element of thermogenic adaptation when someone loses weight i.e. someone who is naturally 80kg will have a higher metabolism than someone who has dieted down to 80kg (assuming other factors are the same).
There are 3 factors which contribute to total metabolism:
- Resting/Basal Metabolic Rate (RMR/BMR)
- Thermic Effect of Food (TEF)
- Thermic Effect of Activity (TEA)
RMR/BMR is based predominantly on amount of LBM and total body weight which LBM requiring more calories than fat mass. Therefore, it is a great idea to preserve as much of this as possible when dieting. Not only this but for the “look good naked” crew this is a necessity 🙂 The TEF is the amount of energy used by the body in the digestion process of foods. Protein is the most complex macronutrient and, therefore, takes the most energy. Fat takes the least amount of energy to metabolize and carbohydrates fall between fat and protein. TEA is comprised of formal exercise and non-exercise activity thermogenisis. (NEAT)
In this article, we are looking at how to lose fat and minimise loss of LBM.
- The most important contributing factor is resistance training and specifically creating enough stimulus in the muscles to convince your body that they are required.
- Adequate dietary protein
- A calorie deficit that is not too large (based on BF%)
It is assumed that the first two factors will be taken care of and the remaining factor is total calorie intake versus total calorie expenditure. When there is an energy deficit the body needs to use stored energy from fat or muscle tissue to provide energy. An obese person will have plenty of fat stores to use as energy and because of this will be able to have a higher calorific deficit than someone who is very lean. The following is an approximate rate of fat loss (whereby maintenance of LBM is possible). The terms are subjective however I will include an approximate BF% also.
Of course all of these numbers will mean nothing if you don’t know your approximate maintenance calories (TDEE). Please see my article on TDEE estimations.