Apparently there’s an old wives’ tale (or I guess a lingering old, discredited idea) that if you eat more acidic foods somehow you wind up leaching calcium from your bones – which could be the case on a low carb diet. But I think studies have disproved this link.
However, I do think there are a lot of complicating factors, especially when it comes to women, and also with people who have diabetes. For instance, a lot of women who have stealth eating disorders may start by having specific, rigid and restrictive dietary plans. And then they wind up malnourished and will develop osteoporosis. So I would imagine a dietitian who hears an unusual or restrictive eating plan might have their ears perked up about this potential. On the other hand, dietitians learn stuff that is about 30 years out of date in a lot of ways, at least from what I can tell. Every time I write an article on a new fad diet, there’s some nutritionist telling me various things that I know have been debunked. Not really sure how the curriculum is developed.
That said, I am not a low-carber and don’t think it’s necessarily healthier for everyone. I think a lot may have to do with your genetic region of origin – if you’re an Inuit or from Mongolia a low-carb diet is for sure the healthiest. If you’re originally from the Indian subcontinent, I doubt it’s the case.