I am only on Day 3 of LCHF, avoiding sugars and starches, but that's about when the habit becomes easier (in spite of staring at a candy jar of skittles on a coworker's desk). And now I have the fire underneath me of "it's this or go through THAT" based on the eye opener about surgery.
Sort of interesting, I've been having MAJOR trouble with energy, like never before. I basically can fall asleep at the drop of a hat (like this morning, filling up my car at the gas station, head back and asleep that second), do not wake feeling rested, take naps at work when no one's looking (either on my long commute I pull over, or I take lunch in the car and sleep). I told a coworker and she said that's how she was when her thyroid tanked (she gained 30lbs in a month). I used to get it checked every couple of years, but it's been 3 years since my last retest. I felt like it had tanked 3 years ago, but that was before the weight gain.
My first thought was sleep apnea, so I'm trying first with diet to see if it resolves the energy issue. But it's bad folks, real bad. Anyway, I'm rambling.