I keep protein at 1-1.5 g per lb of body weight, fat at around 20%, and net carbs at 100-130 g, exercise daily and lift heavy weights (this is at a 20 bmi). My energy is fine. I am not happy at all much lower than 100 net carbs. But, my carbs are from fruit and vegetables. I don't eat starchy vegetables, rice, bread, added sugar, pasta, or packaged foods. I've been doing this for a good five years.