BMR, MMR, BMI, WTF?
-or-Breaking Kleiber’s Law
How do we determine an accurate Basal Metabolic Rate?
■ Accounts for 60-70% of calories used per day.
■ Impacts longevity.
■ Optimal feeding for patients with disease states.
■ Athletic performance.
Conflicting TheoriesAllometric Cascade Theory
BMR = MR0ΣC1(M/M0)
Kleiber’s Law
q0 ~ 73.3*M¾
Kleiber, M. 1961. The Fire of Life. Wiley. 454 p. Hochachka, P., et al. 2003. Allometric cascade: a model for resolving body mass effects on metabolism. Nature.doi:10.1016/S1095-6433(02)00364-1
Strengths of Kleiber’s Law1 2
3
♀ = 1500 ♂ = 1700 = 150
Works across a wide range of species Easy to calculate
Pretty close to what we already believe
Weaknesses of Kleiber’s Law
21
Doesn’t work well with creatures rapidly growing
Struggles to be accurate across a single species
Strengths of Allometric Cascade Theory1
3
♂ = 1603 = 153
2
Super accurate Works well with creatures growing
Even closer to what we believe
Weaknesses of Allometric Cascade Theory1
2
Bad Math
Really complicated
Allometric Cascade Theory is Better Than
What we Have■ Easy enough to generalize for humans.
■ WAY better than Harris Benedict.
■ Can take into account variables such as disease states.
■ Scalable from bacteria to blue whales.
■ Easily modified to take into consideration periods of growth.
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