Primary, secondary, and tertiary sources may all be appropriately used, if (1) they are used without engaging in original research or synthesis and (2) if in the event of conflicts between sources they are treated with the appropriate deference to the better source.
There is some evidence that a low-carbohydrate diet may help people lose weight more quickly than a low-fat diet (31,32)âand may help them maintain that weight loss.
In a review of 94 trials on the efficacy of low-carbohydrate diets from 1966 to 2003, Bravata and colleagues57 reported that weight loss was principally associated with reduced energy intake and not reduced carbohydrate intake.