From paragraph three: "The caloric intake for all the mice was the same."
So, at least in the opinion of these researchers, it is more complicated than calories in vs calories burned. I can think of at least two ways that a mammal might be a less than perfect calorie-processing machine: (1)digestion might not be 100% efficient and confounding factors could alter the how many calories are absorbed or (2)the efficiency with which calories are either burned or stored as fat could vary over time.
Alternately, different feeding patterns could lead to different levels of physical activity and alter the "calories burned" part of your equation. That would produce these results even if food was metabolized with constant efficiency.
So, at least in the opinion of these researchers, it is more complicated than calories in vs calories burned. I can think of at least two ways that a mammal might be a less than perfect calorie-processing machine: (1)digestion might not be 100% efficient and confounding factors could alter the how many calories are absorbed or (2)the efficiency with which calories are either burned or stored as fat could vary over time.
Alternately, different feeding patterns could lead to different levels of physical activity and alter the "calories burned" part of your equation. That would produce these results even if food was metabolized with constant efficiency.