NFS284H1 Chapter Pg. 278-280, 284-285: Week 9 Readings
Document Summary
Calculations of energy needs have been used to generate recommendations about how much energy should be consumed in order to keep body weight stable. Science of measuring heat flow: can determine energy expenditure directly or indirectly. Atp for body processes: accurate method for measuring energy expenditure, expensive and impractical, requires the individual being assessed to remain in isolated chamber throughout procedure to measure heat produced. Physical activity, bmr: can be used to measure total energy needs, not practical in free-living individuals, equipment is too cumbersome for long-term use, doubly-labelled water, more practical method for measuring energy needs. Individual digests/injected with water labelled with isotopes of o2 and h2. Labelled o2 and h2 are used by the body in metabolism. Labelled h2 leaves the body as part of h2o. Labelled o2 leaves the body as part of h2o and co2: different rates of disappearance of the 2 isotopes can be used to calculate the amount of.