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.
Low-carbohydrate diets that were high in vegetable sources of fat and protein modestly reduced the risk of type 2 diabetes. (13) But low-carbohydrate diets that were high in animal sources of protein or fat did not show this benefit.