[adwn]

Body volume scales roughly with the third power of height, while body surface scales roughly with the second power. Therefore, it is possible for the body temperature to stay constant if the basic metabolic rate (i.e., heat generation) per unit of volume decreases between birth and adulthood.

Besides, the human body has several ways of regulating core body temperature: sweating, restricting blood flow to extremities, goose bumbs, and putting on different clothes.

[analog31]

All good points. Do we have measured values for metabolic rate per unit volume as a function of age? This does seem plausible -- building a new body should take more stuff than maintaining an old body.

But I wonder if this translates into different adults saying that they have fast or slow metabolism as an explanation for their weight.