It's interesting reading this thread.
I agree, the science is changing all the time. And a lot of the dietary advice we currently use is outdated and not based on health at all. It is based on overly simplistic reasoning - eat less fat and you will be less fat. People are starting to come around to the understanding that it is sugar (and therefore carbs in general) that are the problem.
A lot of the advice that is given (eg high fibre) is to ameliorate the effect of a less than healthy diet.
I've been eating low carb for a few months and have already lost weight. My sleep is better, my skin is better and I no longer have aching joints.
Low carb is seen as faddy, whereas people see low fat as sensible. People see cake, biscuits and crisps etc as fine as part of a balanced diet. Yet we don't need any of these to live and, once you stop eating them, your sugar cravings lessen, your taste for sweet stuff lessens and you realise that, actually, they don't need to be part of your diet at all!
People have expressed concern that my low carb 'diet' is unhealthy. And that I'm not eating 'properly'. And yet I eat clean, natural food (meat, fish, lots of green veg and salad, a few berries, and healthy and natural fats). I just make sure that I eat very few carbs and my body gets its energy from fat. I don't eat any over processed food or diet food; I don't eat any low fat; I eat real butter rather than spreads; and I cook in olive oil and lard rather than the 'healthier' sunflower oils. Yet my health is better than it's ever been.