Research
Macro partitioning
Replacing saturated fats with monounsaturated or polyunsaturated fats reduces LDL cholesterol without lowering HDL, thereby reducing coronary heart disease risk, whereas replacing saturated fats with carbohydrates may lower HDL and reduce the predicted benefit.
To improve your heart health, focus on swapping saturated fats (like butter and fatty meats) for unsaturated fats (like olive oil, nuts, and fish). Avoid simply replacing fat with refined carbohydrates, as this can lower your good cholesterol (HDL) and reduce the heart benefits.
GoodQualifiesHIGH confidence
Substitution of monounsaturated or polyunsaturated fat for saturated fat reduces LDL levels without appreciably lowering HDL levels... Substitution of carbohydrate for saturated fat in the diet... tends to reduce the serum level of HDL as well as total and low-density lipoprotein (LDL) cholesterol.
Why this rating
Based on multiple metabolic studies and prospective data, though the paper notes direct intervention trials on fat modification have yielded inconsistent results.
Source
Diet and Health: What Should We Eat?
Walter C. Willett · Science · 1994
DOI 10.1126/science.8160011
narrative_reviewCited 1,012×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- High intake of trans fatty acids (partially hydrogenated vegetable fats) increases the risk of coronary heart disease by lowering HDL and raising LDL and lipoprotein(a).Good
- High consumption of vegetables and fruits is associated with a significantly reduced risk of various cancers, including lung, stomach, colon, and oral cancers, primarily due to micronutrients like carotenoids, vitamin C, and folic acid.Good
- Reducing total dietary fat to 30% or less of calories, and saturated fat to less than 10%, is unlikely to have a substantial, sustained effect on body fatness or breast cancer risk, although it may modestly reduce CHD mortality.Good
Related findings · Macro partitioning
- Total daily protein intake of 1.6 g/kg/day is sufficient for maximizing resistance training-induced muscle gains, with an upper confidence interval of 2.2 g/kg/day.Strong
- Resistance exercise training combined with sufficient dietary protein intake acts synergistically to maximize skeletal muscle hypertrophy, with protein intake saturating around 1.6 g/kg/day for general populations and potentially requiring 2.0-2.2 g/kg/day for resistance-trained individuals.Strong
- Trans fats should be completely eliminated from the diet, as they increase LDL cholesterol, decrease HDL cholesterol, and are directly associated with increased coronary risk.Strong
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