THAT is a good point too Duparc. I've noticed that when on very restricted caloric intakes (for me very restricted carbs go along with this) bpth my physical and mental, ESPECIALLY mental energy and creativity has surged. During these periods I went to bed later than normal, and easily woke and became active early in the am. The hungrier I am (chronically) the brighter I feel. My problem is that after a long enough period of restriction I hit a point where I become obsessed with food and thoughts of food completely take over my mind leaving little room for much else.
A little off topic, sorry.