Diet sodas, which are just water plus one or more artificial sweeteners, ought to save tons of calories and help people manage weight and metabolic imbalances, right? You might think so, but that’s not how the research is turning out. A big, complicated study of the effects of diet on “metabolic syndrome” (meaning multiple risk factors for heart disease, diabetes, etc) finds diet soda to be one of the factors associated with predisposition. OK. The study was based on food frequency questionnaires and other results are also hard to interpret but this isn’t the first study to find diet sodas coming out on the wrong side. The artificial sweeteners might be at fault but my guess is that diet sodas are a marker for some of the less healthful dietary practices. You know my rule from What to Eat: never eat anything with anything artificial in it.