What Types of Fat Should We Limit or Avoid for Optimal Heart Health?

November 17, 2025 •

4 min read

Decades of dietary advice have sometimes painted fat with a broad, negative brush, but research shows that distinguishing between 'good' and 'bad' fats is key for long-term health. So, what types of fat should we limit or avoid to ensure we are making the best choices for our cardiovascular system and overall well-being?

Quick Summary

This guide explains which fats to reduce or eliminate from your diet, specifically focusing on the most harmful types: artificial trans fats and saturated fats. Understand their impact on health and learn to replace them with beneficial, heart-healthy unsaturated alternatives found in whole foods.

Key Points

Avoid Trans Fats: The most harmful dietary fat is industrially-produced trans fat, found in partially hydrogenated oils, which raises bad cholesterol and lowers good cholesterol.
Limit Saturated Fats: Found primarily in animal products and some tropical oils, saturated fats should be limited to less than 10% of your daily calories to minimize heart disease risk.
Choose Healthy Unsaturated Fats: Prioritize monounsaturated and polyunsaturated fats, found in foods like olive oil, nuts, and fish, to improve cholesterol levels and reduce heart disease risk.
Read Food Labels: Always check the ingredients list for "partially hydrogenated oil," as products can claim "0 grams" of trans fat if the amount per serving is low.
Make Simple Swaps: Replace solid fats like butter and shortening with healthy liquid oils, and choose lean meats or fish over fatty cuts and processed products.

The Clear and Present Danger of Trans Fats

Trans fat, or trans fatty acid, is a form of unsaturated fat that is considered the most harmful dietary fat for heart health. The majority of trans fats are industrially produced through a process called hydrogenation, which turns liquid vegetable oils into solid fats to increase shelf life and improve texture. While small amounts of natural trans fat exist in some animal products, it is the artificial kind that is most detrimental.

Why Trans Fats Are So Dangerous

Unlike other fats, trans fats simultaneously raise 'bad' low-density lipoprotein (LDL) cholesterol and lower 'good' high-density lipoprotein (HDL) cholesterol. This dual negative effect significantly increases the risk of heart disease, stroke, and type 2 diabetes. The creation of artificial trans fats has been banned in the United States and many other countries due to these profound health risks.

Foods High in Artificial Trans Fats

Even with bans in place, it is vital to read ingredient lists, as products containing less than 0.5 grams per serving can be labeled as having "0 grams" of trans fat. Look for "partially hydrogenated oil" or "hydrogenated oil" to identify these items. Common sources to avoid include:

Commercially baked goods: Cookies, cakes, pastries, and biscuits often contain partially hydrogenated oils.
Fried foods: French fries, doughnuts, and other deep-fried fast-food items are notorious sources.
Processed snack foods: Crackers, microwave popcorn, and certain packaged snacks may contain hidden trans fats.
Solid fats: Stick margarine and some vegetable shortening are major culprits.

The Mixed Verdict on Saturated Fats

Saturated fats, which are typically solid at room temperature, are not as harmful as artificial trans fats, but still warrant limitation in a healthy diet. Most saturated fat comes from animal sources, but some plant-based oils also contain it. Diets high in saturated fat can raise total cholesterol and LDL ('bad') cholesterol, increasing the risk of heart disease. Health authorities generally recommend limiting saturated fat intake to less than 10% of daily calories.

Where Saturated Fats Lurk

Reducing your intake means being mindful of these common foods:

Fatty cuts of meat: Beef, pork, and lamb are often high in saturated fat.
High-fat dairy: Full-fat cheese, butter, whole milk, cream, and ice cream are significant sources.
Poultry skin: Leaving the skin on chicken or turkey adds saturated fat.
Certain tropical oils: Coconut oil and palm oil are high in saturated fat, contrary to some popular health trends.

Making Healthier Fat Choices

Rather than eliminating all fat, the goal is to replace unhealthy fats with healthier, unsaturated options. Monounsaturated and polyunsaturated fats, which are liquid at room temperature, offer significant health benefits, including lowering LDL cholesterol and reducing inflammation. These fats are found in a variety of plant-based foods and fish.

Healthier Alternatives

Here are some simple swaps to incorporate more healthy fats:

Cooking oils: Use olive, canola, sunflower, or avocado oil instead of butter or shortening.
Protein sources: Choose fatty fish like salmon or trout, or plant-based proteins like beans and legumes, over fatty red meats.
Snacks: Snack on nuts and seeds instead of processed snack foods.
Spreads: Opt for avocado or hummus on bread instead of butter or margarine.

Table: Comparing Unhealthy and Healthy Fats


Feature	Trans Fats (Artificial)	Saturated Fats	Unsaturated Fats (Mono/Poly)
Physical State	Solid at room temperature	Solid at room temperature	Liquid at room temperature
Primary Sources	Processed baked goods, fried foods, stick margarine	Fatty meats, high-fat dairy, coconut oil, butter	Vegetable oils, nuts, seeds, avocados, fatty fish
Cholesterol Impact	Increases LDL ('bad'), lowers HDL ('good')	Increases LDL ('bad')	Lowers LDL ('bad'), may raise HDL ('good')
Heart Health Risk	High risk, linked to heart disease and stroke	Increased risk of heart disease	Lowers risk of heart disease
Dietary Recommendation	Avoid completely	Limit intake (less than 10% daily calories)	Prioritize over other fats

Conclusion: A Conscious Approach to Fats

Navigating the world of dietary fats doesn't mean banishing them entirely, but rather making informed, conscious choices. The verdict is clear: artificial trans fats, found in partially hydrogenated oils, should be avoided entirely due to their destructive impact on cholesterol levels and heart health. Saturated fats, while less harmful, are best consumed in moderation, with guidance to stay under 10% of total daily calories. By actively replacing these 'bad' fats with the 'good' unsaturated fats from sources like avocados, nuts, seeds, and olive oil, you can significantly improve your cardiovascular health and overall well-being. For a deeper scientific dive into the nuances of dietary fat, explore the information available at Harvard Health.

Making Smart Swaps for a Healthier Diet

To put these recommendations into practice, consider some simple culinary changes. For instance, when cooking, replace butter with olive oil, or use avocado instead of butter on toast. Instead of a meaty burger, opt for a fish fillet, which provides beneficial omega-3 fatty acids. These small adjustments can have a major impact on your long-term health without sacrificing flavor or enjoyment. Reading food labels carefully and choosing whole, unprocessed foods are your best strategies for ensuring a healthy balance of fats in your diet.

Frequently Asked Questions

Saturated fats are typically solid at room temperature and primarily come from animal products and tropical oils. Unsaturated fats are liquid at room temperature and are found in plant-based sources like seeds, nuts, and vegetable oils.

Artificial trans fats are considered the most dangerous because they uniquely raise 'bad' LDL cholesterol while simultaneously lowering 'good' HDL cholesterol, significantly increasing the risk of heart disease and stroke.

The most reliable method is to check the ingredient list for 'partially hydrogenated oil.' Due to labeling regulations, products with less than 0.5 grams of trans fat can still be labeled as zero grams per serving.

To reduce saturated fat intake, use healthy vegetable oils like olive, canola, or sunflower oil instead of butter, lard, or coconut oil.

Not all fats from meat are equally harmful. While fatty cuts of red meat are high in saturated fat and should be limited, leaner cuts and poultry without the skin contain less saturated fat. Some fish contain healthy omega-3 fatty acids.

Yes, health guidelines suggest that saturated fat should be limited to a small percentage of your daily calories, typically less than 10%. The goal is moderation and replacing it with healthier fats, not total elimination.

No. While avoiding trans fat is a positive step, many processed foods may still contain other unhealthy ingredients like high amounts of saturated fat, sugar, or sodium. It's important to consider the overall nutritional profile.