For people at high risk of cardiovascular disease, the recommended limit for total cholesterol is 4 mmol/L, and 2 mmol/L for LDL.In the United States, the National Heart, Lung, and Blood Institute within the National Institutes of Health classifies total cholesterol of less than 200 mg/dL as "desirable", 200 to 239 mg/dL as "borderline high", and 240 mg/dL or more as "high".There is no absolute cutoff between normal and abnormal cholesterol levels, and values must be considered in relation to other health conditions and risk factors.Higher levels of total cholesterol increase the risk of cardiovascular disease, particularly coronary heart disease. Levels of LDL or non-HDL cholesterol both predict future coronary heart disease; which is the better predictor is disputed. High levels of small dense LDL may be particularly adverse, although measurement of small dense LDL is not advocated for risk prediction. In the past, LDL and VLDL levels were rarely measured directly due to cost. Levels of fasting triglycerides were taken as an indicator of VLDL levels (generally about 45% of fasting triglycerides is composed of VLDL), while LDL was usually estimated by the Friedewald formula:
LDL 
  
    
      
        ≈
      
    
    {\displaystyle \approx }
   total cholesterol – HDL – (0.2 x fasting triglycerides).However, this equation is not valid on nonfasting blood samples or if fasting triglycerides are elevated (>4.5 mmol/L or >∼400 mg/dL).
Treatment
Treatment recommendations have been based on four risk levels for heart disease. For each risk level, LDL cholesterol levels representing goals and thresholds for treatment and other action are made. The higher the risk category, the lower the cholesterol thresholds. For those at high risk, a combination of lifestyle modification and statins has been shown to decrease mortality. Lifestyle
Lifestyle changes recommended for those with high cholesterol include: smoking cessation, limiting alcohol consumption, increasing physical activity, and maintaining a healthy weight.Overweight or obese individuals can lower blood cholesterol by losing weight – on average a kilogram of weight loss can reduce LDL cholesterol by 0.8 mg/dl. Diet
Eating a diet with a high proportion of vegetables, fruit, dietary fibre, and low in fats results in a modest decrease in total cholesterol.Eating dietary cholesterol causes a small rise in serum cholesterol, the magnitude of which can be predicted using the Keys and Hegsted equations. Dietary limits for cholesterol were proposed in United States, but not in Canada, United Kingdom, and Australia. However, in 2015 the Dietary Guidelines Advisory Committee in the United States removed its recommendation of limiting cholesterol intake.A 2020 Cochrane review found replacing saturated fat with polyunsaturated fat resulted in a small decrease in cardiovascular disease by decreasing blood cholesterol. Other reviews have not found an effect from saturated fats on cardiovascular disease.