Which type of fat raises cholesterol and increases the risk of coronary heart disease?

October 27, 2025 •

3 min read

According to the World Health Organization, more than 278,000 deaths each year globally are attributed to the intake of industrially produced trans fat alone. While all fats are not created equal, two types of fat are particularly notorious for raising cholesterol levels and increasing the risk of coronary heart disease: saturated fat and trans fat.

Quick Summary

Saturated and trans fats raise 'bad' LDL cholesterol and increase heart disease risk. This article details the impact of these fats, explains their food sources, and provides actionable tips for making healthier dietary choices to improve cardiovascular health. It focuses on limiting unhealthy fats and incorporating heart-healthy alternatives.

Key Points

Harmful Fats: Saturated fat, from animal products and tropical oils, and trans fat, from industrially hydrogenated oils, are the types that raise bad LDL cholesterol and increase heart disease risk.
Trans Fat's Double Whammy: Trans fat is particularly harmful, as it both raises LDL ('bad') cholesterol and lowers HDL ('good') cholesterol.
Healthy Replacements: Substituting saturated and trans fats with unsaturated fats—like those found in olive oil, avocados, nuts, and oily fish—can improve cholesterol levels and heart health.
Identify and Avoid: Always check food labels for 'saturated fat' and 'partially hydrogenated oils' to limit intake of unhealthy fats.
Prioritize Whole Foods: Reducing consumption of processed snacks, commercial baked goods, and fried foods is key to decreasing exposure to these harmful fats.
Portion Control and Preparation: Making smart cooking choices, such as grilling or baking instead of frying, and choosing lean cuts of meat can help lower saturated fat intake.

Saturated Fat: The Silent Culprit

Saturated fats are molecules 'saturated' with hydrogen atoms, making them typically solid at room temperature. They are found predominantly in animal products and some plant-based oils. Decades of scientific research have established that a diet high in saturated fat can raise low-density lipoprotein (LDL) cholesterol, often dubbed 'bad' cholesterol. High levels of LDL cholesterol can lead to the buildup of fatty plaques (atherosclerosis) in the arteries, narrowing them and restricting blood flow to the heart.

Common Sources of Saturated Fat

Fatty meats: Bacon, sausage, ribs, and processed meats.
Full-fat dairy: Butter, cream, cheese, and whole milk.
Tropical oils: Coconut oil and palm oil.
Baked goods: Cookies, cakes, and pastries often made with butter or shortening.

Trans Fat: The Most Harmful Type

Trans fats, or trans fatty acids, are created through an industrial process called hydrogenation, which adds hydrogen to liquid vegetable oils to make them more solid. This process makes them extremely stable, giving foods a longer shelf life and satisfying texture. However, they are also considered the most harmful type of dietary fat for the heart. Trans fats not only raise LDL cholesterol but also lower high-density lipoprotein (HDL) cholesterol, the 'good' cholesterol that helps remove excess cholesterol from the arteries.

Where Trans Fat Lurks

Industrially produced trans fats: Historically found in margarine, commercial baked goods, and fried fast food. While many countries have banned or restricted their use, it is still crucial to check food labels for 'partially hydrogenated oils'.
Naturally occurring trans fats: Found in small amounts in meat and dairy products from ruminant animals like cows and sheep.

The Difference Between Healthy and Unhealthy Fats

In contrast to saturated and trans fats, monounsaturated and polyunsaturated fats are considered 'heart-healthy'. These fats can actually improve blood cholesterol levels when they replace unhealthy fats in the diet. They are typically liquid at room temperature and found in plant-based foods and oily fish.

Comparison of Fat Types


Feature	Saturated Fat	Trans Fat	Unsaturated Fat
State at Room Temp	Solid	Solid (from hydrogenation) or Liquid (naturally occurring)	Liquid
Effect on LDL ('Bad') Cholesterol	Increases	Increases most significantly	Decreases
Effect on HDL ('Good') Cholesterol	Minimal to slight increase	Decreases	Increases or maintains
Risk of Heart Disease	Increases	Increases most significantly	Decreases
Common Sources	Red meat, butter, cheese, tropical oils	Processed snacks, fried foods, baked goods	Olive oil, avocados, nuts, oily fish

Making Heart-Healthy Dietary Choices

Making simple swaps can significantly reduce your intake of unhealthy fats and lower your risk of coronary heart disease. Here are some actionable steps:

Choose Lean Meats: Trim all visible fat and remove the skin from poultry. Opt for leaner cuts of beef like sirloin or round.
Use Healthy Cooking Oils: Replace butter, lard, or coconut oil with vegetable oils rich in unsaturated fats, such as olive, canola, or sunflower oil.
Eat More Fish: Aim for at least two servings of oily fish, such as salmon, mackerel, or trout, per week. These are excellent sources of omega-3 polyunsaturated fats.
Go Plant-Based: Incorporate more beans, legumes, nuts, and seeds into your diet. For example, add ground flaxseed to yogurt or walnuts to salads.
Read Food Labels: Always check the nutrition facts panel for 'saturated fat' and the ingredients list for 'partially hydrogenated oil' to identify and avoid trans fats. The American Heart Association recommends keeping saturated fat intake to less than 6% of total daily calories.
Limit Processed Foods: Reduce consumption of fried foods, commercial baked goods, and fast food, as they are often high in saturated and trans fats.

Conclusion

Understanding which type of fat raises cholesterol is vital for preventing coronary heart disease. While all fats contain calories, saturated and, most importantly, trans fats have a direct and negative impact on blood cholesterol levels and heart health. By actively limiting these harmful fats and replacing them with heart-healthy unsaturated alternatives, individuals can take significant control over their cardiovascular wellness. A conscious, educated approach to dietary fat intake is a powerful step toward a healthier heart.

This article is for informational purposes only and does not constitute medical advice. For personalized dietary recommendations, please consult with a healthcare provider or a registered dietitian.

Frequently Asked Questions

Saturated fats are typically solid at room temperature and found mainly in animal products. Unsaturated fats are usually liquid at room temperature and found in plant-based sources and fish. Healthy unsaturated fats can improve cholesterol levels, while saturated fats can raise 'bad' LDL cholesterol.

Trans fats are particularly detrimental to heart health. They increase 'bad' LDL cholesterol while also lowering 'good' HDL cholesterol, leading to a significantly higher risk of coronary heart disease.

Industrially produced trans fats, created through hydrogenation, are not part of a healthy diet and should be avoided entirely. While ruminant trans fats found naturally in meat and dairy are also harmful, the highest concentrations are from industrial sources.

For heart-healthy cooking, swap butter and solid fats for vegetable oils rich in unsaturated fats, such as olive, canola, or sunflower oil. When sautéing, you can also use low-salt vegetable stock to reduce fat entirely.

To reduce saturated fat, choose leaner cuts of meat, opt for low-fat dairy products, trim visible fat from poultry, and replace animal fats with plant-based oils and spreads. Comparing food labels and choosing products with less than 1.5g of saturated fat per 100g is also effective.

Yes. Despite its popularity, coconut oil is almost entirely composed of saturated fat—more than butter—and is likely to cause the same cholesterol-raising issues.

High levels of LDL cholesterol can lead to atherosclerosis, the buildup of fatty plaques in the arteries. This narrowing can block blood flow, increasing the risk of a heart attack or stroke.