“However, in Russia, physiologists always remember to include the brain in their calculations, and it turns out that a walk through interesting and pleasant surroundings consumes more energy than does harder but more boring exercise. An active brain consumes a tremendous amount of fuel.”

Of additional interest, perhaps:

“Exertion and stress have in common the need for more fuel.”

And:

“Even in rich cultures, protein deficiency, inappropriate exercise, and emotional tension will contribute to premature aging of the individual, and damage to the offspring.”

~Ray Peat