What Kind of Fat Is Not Healthy?

January 10, 2026 •

3 min read

Globally, over 278,000 deaths annually are linked to industrially produced trans fats. This highlights the necessity of understanding the kind of fat that is not healthy and its direct correlation to cardiovascular diseases.

Quick Summary

This article discusses unhealthy fats, specifically trans fats and saturated fats, and their impact on cholesterol and heart health, while offering guidance on identifying and reducing their intake.

Key Points

Trans Fat Is The Worst: Artificially created trans fats, from partially hydrogenated oils, are the most harmful type of fat, with no safe level of consumption.
Saturated Fat Should Be Limited: Found mainly in animal products and tropical oils, excessive saturated fat intake can raise 'bad' LDL cholesterol and increase heart disease risk.
Unsaturated Fat Is 'Good': Monounsaturated and polyunsaturated fats, found in plants and fish, can help lower cholesterol and reduce heart disease risk.
Read Ingredient Labels Carefully: Always check the ingredients list for "partially hydrogenated oil" to identify and avoid hidden trans fats in processed foods.
Choose Healthier Replacements: Replace unhealthy fats (e.g., butter, fried foods) with healthier options like olive oil, nuts, and avocados.
Limit Processed Foods: Fried foods, baked goods, and many packaged snacks are primary sources of unhealthy fats and should be consumed sparingly.

Identifying Unhealthy Fats

While some fats are essential for health, such as those that provide energy, enable vitamin absorption, and build cells, others, namely trans fats and excessive saturated fats, can be harmful.

The Negative Effects of Trans Fat

Trans fat is considered the unhealthiest dietary fat and offers no health benefits. Its use has been restricted due to the significant health risks.

Origin: Most trans fats are artificially made through partial hydrogenation, solidifying liquid oils and increasing shelf life.
Health Impact: Trans fat raises LDL and lowers HDL cholesterol, which can cause artery blockages and increases the risk of heart attack, stroke, and type 2 diabetes.
Sources: Common sources include commercially baked goods, fried foods, stick margarine, vegetable shortening, and processed snacks.
Identification: Look for "partially hydrogenated oil" on ingredient lists. Labels can claim "0 grams trans fat" even if small amounts exist.

The Issues with Saturated Fat

Saturated fat is typically solid at room temperature and is found in animal products and some tropical oils. It has been restricted due to its link to increased LDL cholesterol. Current understanding is more nuanced, but limiting intake is still advised by most experts.

Mechanism: A high intake of saturated fat can increase total and LDL cholesterol, possibly leading to blocked arteries.
Research: Some studies suggest that replacing saturated fat with polyunsaturated fat reduces heart disease risk, while replacing it with processed carbs does not. The source of saturated fat may also matter, as processed meats could be more harmful than some dairy.
Sources: Common sources include fatty red and processed meats, high-fat dairy, lard, and tropical oils like coconut and palm oil.
Recommendations: The American Heart Association suggests limiting saturated fat to less than 6% of daily calories, approximately 13 grams for a 2,000-calorie diet.

Comparing Healthy and Unhealthy Fats


Feature	Saturated Fats (Unhealthy)	Trans Fats (Most Unhealthy)	Unsaturated Fats (Healthy)
State at Room Temp	Solid	Solid	Liquid
Primary Sources	Animal products, tropical oils	Processed and fried foods, partially hydrogenated oils	Plant-based oils, nuts, seeds, fatty fish
Effect on LDL ('Bad') Cholesterol	Increases	Significantly increases	Decreases
Effect on HDL ('Good') Cholesterol	Negligible or can increase (depending on source)	Significantly lowers	Increases
Health Impact	Can increase heart disease risk if consumed excessively	Increases heart attack, stroke, and diabetes risk	Supports heart health and lowers disease risk

Healthier Fat Choices

Healthier choices involve substituting unhealthy fats with beneficial ones instead of replacing them with refined carbohydrates.

Use olive oil for cooking instead of butter.
Choose lean protein sources such as fish, poultry (skinless), and legumes over fatty red and processed meats.
Check labels for "partially hydrogenated oil" and choose low-saturated fat products.
Choose nuts, seeds, or avocados as snacks instead of processed options.
Prioritize grilling, baking, or steaming foods over frying.

Conclusion

While dietary fat is necessary, the type consumed has a critical impact on health. Industrially produced trans fats are the most harmful and should be completely avoided. Saturated fats, while less severe, should be limited and preferably from less processed sources. Prioritizing unsaturated fats from whole foods while reducing trans and saturated fat intake promotes better heart health and overall well-being. A balanced approach to fat consumption is key for a healthier lifestyle.

Frequently Asked Questions

Saturated fats are solid at room temperature, found in animal products and some tropical oils. Unsaturated fats are liquid and are found in plant-based oils, nuts, and seeds.

Trans fats raise harmful LDL cholesterol while lowering beneficial HDL cholesterol, increasing the risk of heart disease, stroke, and diabetes.

Check the ingredient list for "partially hydrogenated oil." Even with "0g trans fat" on the nutrition facts, small amounts may be present.

Recent research suggests the effect of saturated fat can depend on its food source. Although limiting saturated fat is still recommended, saturated fat from processed meats may be more concerning than that from some dairy products.

Substitute unhealthy fats with monounsaturated and polyunsaturated fats, such as using olive oil instead of butter, avocados in place of cheese, and nuts or seeds as snacks.

The American Heart Association advises a dietary pattern that gets less than 6% of total daily calories from saturated fat.

A high intake of unhealthy fats, particularly trans and saturated fats, is associated with increased risk of heart disease, stroke, high cholesterol, type 2 diabetes, and general inflammation.