Ever wondered what happens to the fat when you lose weight?
There is widespread misconceptions about how humans lose weight among general practitioners, dietitians, and personal trainers.
Most people believed that fat is converted to energy or heat, this misconception may be caused by the “energy in/energy out” mantra, which violates the law of conservation of mass, which implies that mass can neither be created nor be destroyed, the same as energy, although it may be rearranged in space. For example during any chemical reaction in an isolated system the total mass of reactants or starting material must be equal to the mass of the products.
Other misconceptions are that the metabolites of fat are excreted in the faeces or converted to muscle.
Let's first understand how we get fat:
Excessive carbohydrates (from your chips, fast foods, Colas etc.) or proteins (yes even excessive proteins) is converted to TRIGLYCERIDE and stored in lipid droplets of adipocytes (the fat cells). So if we are aiming for lowering the body fat percentage while maintaining the fat free mass (which may be hard to determine) are just trying to get rid of the stored triglycerides.
Novel Calculations by Meerman and Brown at the University of New South Wales, Australia show that if triglyceride has to be metabolised (or in chemical terms oxidised), the chemical formula looks like this:
C55H104O6+78O2→55CO2+52H2O+energy
Meaning:
Complete oxidation of 10 kg of human fat requires 29 kg of inhaled oxygen producing 28 kg of CO2 and 11 kg of H2O. The CO2 is excreted chiefly by lungs (so they are your primary organ for losing WEIGHT!!, SO no SMOKING folks!!), and the water is excreted through urine, feaces, sweat, breath,tears or other bodily fluids.
To quote the Authors:
Lifting the veil on weight loss
At rest, an average 70 kg person consuming a mixed diet (respiratory quotient 0.8) exhales about 200 ml of CO2 in 12 breaths per minute. Each of those breaths therefore excretes 33 mg of CO2, of which 8.9 mg is carbon. In a day spent asleep, at rest, and performing light activities that double the resting
metabolic rate, each for 8 hours, this person exhales 0.74 kg of CO2 so that 203 g of carbon are lost from the body.
For comparison, 500 g of sucrose (C12H22O11) provides 8400 kJ (2000 kcal) and contains 210 g of carbon.
Replacing one hour of rest with exercise that raises the metabolic rate to seven times that
of resting by, for example, jogging, removes an additional 39 g of carbon from the body, raising the total by about 20% to 240 g.
For comparison, a single 100 g muffin represents about 20% of an average person’s total daily energy requirement. Physical activity as a weight loss strategy is, therefore, easily foiled by relatively small quantities of excess food (A lesson for me no cheat foods!!)..
This article can be accessed at :BMJ 2014;349:g7257 doi: 10.1136/bmj.g7257 (Published 16 December 2014).
Disclaimer:
This blog is intended for the purpose of dissemination of information. All Sources have been cited and the author doesn't claim any right over the information. The information was present as open access.
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