99% of civilians don’t know what a healthy running dog should look like so just ignore them but if someone who has good a running dog mentions something then it’s worth having a think.
The only reason I mention this statement of the obvious is that if her behaviour noticeably changes when she eats more food, then you might not be giving her enough calories. Dogs shouldn’t have more noticeably 'energy' if they are at the right weight and given more food - but they could appear that way if they are not getting enough calories in the first place.
I’ve had problems getting enough muscle/fat