Just a fad? Or a genuine way to lose weight & improve your health? I've read articles which say that low carb diets are actually what your body is designed to eat, what our ancestors ate, and that foods like breads and rice and pasta are not good for you. Plenty of people have lost weight on low carb diets; some doctors even recommend it as a viable weight loss method. On the other hand, the brain needs a constant stream of glucose to function properly, and I'm thinking a protein-heavy diet might tax your body a little bit as it tries to obtain the necessary glucose it needs from a limited stock. Plus, a low carb diet would probably be difficult to maintain long term. And there's the ethical issue of eating mostly meat vs. mostly plants (which is usually what a low carb diet involves); many animals face slaughter because of how we humans eat. It would get worse if all of humanity switched to a mainly protein based diet.