One problem with a low carb diet is that it can cause your LDL (or "bad") cholesterol to rise. As I have explained before, this is not necessarily bad, as long as the LDL particles are large and fluffy, not small and dense.
Now a recent research study suggests that the "bad" cholesterol is not as bad as previously thought. In this study, people who exercised and gained muscle mass had the highest LDL levels, a surprising finding. I enjoyed reading how the researchers had to spin the findings, since exercise and gaining muscle mass is generally considered a good thing. More ammunition that the "bad" cholesterol is not always bad.