It is as if eating carbs leaches out all my pep, vim and vigour. My limbs get heavy, I need more sleep (but it is less satisfying), by concentration and memory deteriorate. The thought of walking down to the corner shop is so off putting that I change the evening's menu rather than go out and buy a single ingredient...
On the other hand, when eating low carb (after the initial adjustment phase), I feel great! I potter about finding things to do, add an extra loop to the dog walk, do extra housework, keep focused for hours. It is like being a different person.