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Updated: Aug 17, 2026

Determining Basal Energy Expenditure and the Capacity of Thermogenic Adipocytes to Expend Energy in Obese Mice
Published on: November 11, 2021
Digestive adaptations for fueling the cost of endothermy
Abstract:
Little is known about the digestive adaptations that enable mammals to sustain metabolic rates an order of magnitude higher than those of reptiles. Comparison of several features of digestion in mammals and lizards of similar size eating the same diet revealed that mammals processed food ten times faster and with the same or greater extraction efficiency. Transport kinetics and rates of nutrient absorption normalized to the quantity of intestinal tissue were similar in these two classes of vertebrates. The main basis for faster absorption in mammals is their much greater intestinal surface area.
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