On diets, mostly, and I read up on every one I've tried. :P So I can tell you that the increased release of ketones in a lower carbohydrate diet will put you into ketosis, which causes bad breath and stinky urine. I could tell you that different metabolic rates process food differently, and you might be a high-burner, medium-burner or low-burner when it comes to metabolism, but how you process your food is more important than what you eat. Which is why some people gain weight on grains and fruits while others gain weight (or increased cholesterol levels) on higher fat diets. You can check your metabolism burn rate with some easy tests. One's online here: http://www.proprofs.com/quiz-school/story.php?title=metabolic-typing-test_1