2 ms·
According to this paper, this is not true. The weight is exhaled as CO2. http://www.bmj.com/content/349/bmj.g7257 http://www.bmj.com/content/349/bmj.g7257 >>
by cromulent 10y ago
According to this paper, this is not true. The weight is exhaled as CO2.
http://www.bmj.com/content/349/bmj.g7257 http://www.bmj.com/content/349/bmj.g7257
>> Most people believed that fat is converted to energy or heat, which violates the law of conservation of mass. We suspect this misconception is caused by the “energy in/energy out” mantra and the focus on energy production in university biochemistry courses.
- wenc 10y agoEnthalpy (note, not energy) is an extensive property, and is proportional to the mass/size of the system, so mass is already accounted for. CO2's enthalpy can be represented in the same equation. The energy balance equation is a fundamental thermodynamic equation. It is inherently coupled with mass balance equations. If we didn't get this right, we wouldn't have been able to design chemical reactors all these years. Unfortunately because enthalpy is a more abstract concept, it isn't very appealing to folks who like simplifications like calories in = calories out. It is, however, the correct concept.