Most self test systems give the following ideas of what is "normal"
Less than 200 mg/dL 'Desirable' is normally said to be the level that puts you at lower risk for heart disease. A cholesterol level of 200 mg/dL or greater is said to increase your risk.
200 to 239 mg/dL 'Borderline-high.'
240 mg/dL and above 'High' blood cholesterol. A person with this level has more than twice the risk of heart disease compared to someone whose cholesterol is below 200 mg/dL.
HDL cholesterol - High density lipoproteins (HDL) is the 'good' cholesterol. HDL carry cholesterol in the blood from other parts of the body back to the liver, which leads to its removal from the body. So HDL help keep cholesterol from building up in the walls of the arteries.
Here are the HDL-Cholesterol Levels that matter to you:
Less than 40 mg/dL A major risk factor for heart disease
40 to 59 mg/dL The higher your HDL, the better
60 mg/dL and above An HDL of 60 mg/dL and above is considered protective against heart disease.
However there is no real consensus as to what causes cholesterol to increase. Large amounts are created by the body and are not necessarily related to dietary consumption. Both Atkins and Dr Eades writing in protein power have suggested that far from increasing cholesterol their diets should be beneficial in lowering the cholesterol.
All suggest checking the levels before you commence the diet.
It is not clear when you had the previous test and you do not say what the HDL level was.
I am not a Dr. so cannot give you any medical advice, but I do believe the Dr's Atkins and Eades in this respect - of itself a low carbohydrate diet should not have an adverse effect on blood cholesterol.
However there is a lot of good threads and research articles on this site about "good" fats and "bad" fats. This is worth further research before all saturated fats are consigned to the waste bin.
Exercise however is always good advice.