Incidentally, I have a lady I've been run training for a few years who after listening to me rave about high fat low carb (and apparently watching my body change shape dramatically over the last couple of years) tried it.
She's 68 and had 'significant health issues' (and an addiction to bread and crisps apparently). In just over eight weeks she's lost nearly two stone and has had to significantly reduce blood pressure medication after logging a 100/68.
More importantly, she looks really well. She has a glow and shine in her eyes I've never seen before. The change is truely remarkable and lots of people in the run club have commented on it.