The short answer is no – fat cannot be directly transformed into muscle. Fat and muscle are two different tissues. You can increase muscle mass while you decrease fat mass, but fat is not converted into muscle. In the same way muscle cannot be converted into fat. Fat is created whenever we take in excess calories from fat, protein, carbohydrate (or alcohol). In this case the calories ultimately end up being converted to triglyceride and stored in fat cells.
Each molecule of triglyceride (fat) consists of carbon, hydrogen and oxygen. To get rid of a single molecule of triglyceride takes many enzymes and biochemical steps to completely oxidize fat. The complete oxidation of 22lbs of fat requires 63lbs of oxygen consumption and the production of 62lbs of carbon dioxide and 24lbs of water. The carbon dioxide is excreted by the lungs while the water is excreted as urine, sweat, breath, tears or other bodily fluids.
Building muscle is a whole different process. Three key mechanisms are responsible for initiating muscle growth:
Muscle Tension – all forms of resistance training force muscles to create tension to support and move the load. When enough tension is created this causes changes in the chemistry of the muscle allowing growth factors to be secreted along with satellite cell activation.
Tension can come from active tension when muscles actively contract and also from passive tension which is stretching which tends to occur during the lengthening (eccentric) phase of a resistance training exercise.
Active tension tends to result in muscle fibers becoming wider while passive tension can make them longer.
Muscle Damage – damage to muscle cells causes a release of inflammatory chemicals and immune cells that activate satellite cells to come into action. This also initiates muscle growth.
Metabolic Stress – When you feel the “burn” or the “pump” when lifting weights, you are feeling the effects of metabolic stress. Metabolic stress from high levels of anaerobic energy production helps contribute to muscle growth. The muscles adapt to this type of challenge by storing higher levels of glucose, creatine, and fluid. This type of growth is often referred to as “Sarcoplasmic Hypertrophy” and produces larger muscles - think body builder muscles.
Resistance training that focuses purely on maximal muscle tension without a lot of metabolic stress like Power Lifting causes more “Myofibrillar Hypertrophy” which refers to more growth of the actual tension producing muscle fibers called myofibrils without pronounced increases in fluid and glucose. Pure Power Lifters are very strong but their muscles are not as large because their training focuses purely on maximal tension meaning lifting heavier weight for less repetitions with more rest between sets.
Most strength training results in a combination of sarcoplasmic and myofibrillar hypertrophy depending on the levels of tension produced, the length of sets of exercises, and recovery time used between sets.
In summary, for muscle building to occur you must force your muscles to adapt by creating stressors including increased tension, muscle damage, and metabolic stress and then eating properly and resting to allow the muscles to recover and grow.
