Biochemistry Do calories matter? In a word, yes. But, technically this is the wrong question. Biochemistry Why Weight Watchers is actually a low carb diet Invariably I get asked the question, “If carbohydrates are so bad, why did [so-and-so] lose weight on the [such-and-such] diet?”, where “such-and-such” diet is not a “low-carb” diet. Obviously, this is an important question and a pretty complex one.