This is probably one of the best and clearest explanation of cholesterol, HDL, LDL, sdLDL, triglycerides and “when to worry” presented by an Australian referencing lots of science.
The following screenshot was from the above video. It shows the impact of a LCHF (Low carb high fat) diet on Cholesterol:
So a LCHF diet has a great impact on reducing the “small dense LDL” which is the “dangerous” type of LDL to have high amounts of, as well as reducing the Triglycerides. It is the “diet” to be on when you have cholesterol issues and metabolic syndrome/insulin resistance issues (26:09).
It was also surprising to find out that Triglyceride readings themselves are a poor indicator of Triglycerides in the blood as they can vary wildly from day to day (25:29). HDL which is a better indicator of the triglycerides in the blood as it is related to triglycerides but does not jump around like triglyceride levels.
Total Cholesterol/HDL ratio is the best indicator for the risk of heart disease as it takes into account small dense ldl levels by using HDL which is inversely related to “real” average triglycerides in the blood which then related to small dense ldl levels.