Fat or lipid metabolism is the breakdown of fatty acids to generate energy or to synthesize
new lipids i.e. your body is either in a ‘fat burning’ or ‘fat storing’ state. Metabolized fat
plays an integral role in human health, it is stored as energy, provides insulation for body
warmth and protects your organs.
The rate that fat is metabolized depends on a number of factors including gender, hydration,
dietary consumption, liver functionality, insulin sensitivity and activity level. Fat metabolism
can be increased or decreased based on these variables: it can be increased using the
ketogenic diet , or decreased in the case of obesity .
Typically when carbs are consumed your body metabolizes them as the preferred fuel source
– also known as being in a ‘fed state’ or ‘absorptive state’ – meaning you’re storing fat. If
energy is required by the body the food will be used, but if it isn’t, the excess glucose is
stored as glycogen in the liver and muscle cells or as fat in adipose tissue.
When the body is in a fasted or ‘postabsorptive state’ i.e. no food has been consumed, the
body relies solely on stored glycogen for energy. If glycogen stores have been depleted as in
the ketogenic diet, the body adjusts into a fat burning state.
During fat metabolism, enzymes including hormone sensitive lipase and lipoprotein lipase
move the stored fat from adipose tissue into the bloodstream to use as energy, with the help of
the hormone epinephrine. The fat stores are oxidized into fatty acids and glycerol, which can
be absorbed for use easily. This metabolism of fat is known as lipolysis.