Good Fats vs. Bad Fats: What you Need to Know About Dietary Fat
For years, dietary fat was blamed for everything from weight gain to heart disease. Today, research shows that not all fats are created equal. Understanding the difference between healthy fats and unhealthy fats can help support heart health, hormone balance, weight management, brain function, and overall wellness. Today, we know the conversation is much more nuanced. Fat is not inherently “bad” in fact, it is essential for hormone production, brain function, nutrient absorption, satiety, and overall health.
The key is understanding the type of fat you are eating, how much you are consuming, and where those fats are coming from.
In this post, we’ll break down:
The different types of fats
Which fats are considered more beneficial for health
Examples of foods containing each type
Recommended daily intake ranges
What fat intake actually looks like in real life
Health risks of consuming too much of certain fats
Whether cooking oils really matter
Why Your Body Needs Healthy Fats
Dietary fat plays a critical role in overall health and nutrition. Healthy fats are essential for several important functions in the body:
Helps absorb fat-soluble vitamins A, D, E, and K
Supports hormone production
Provides long-lasting energy
Protects organs and supports cell structure
Aids brain and nervous system function
Helps with satiety and blood sugar stability
Without enough fat, many people notice:
Increased hunger
Fatigue
Dry skin
Poor recovery from exercise
Hormonal changes
Difficulty absorbing nutrients
The goal is not to avoid fat, it’s to choose better sources most of the time.
The Main Types of Dietary Fat Explained
Unsaturated Fats (Healthy Fats)
Unsaturated fats are often considered the healthiest types of dietary fats. Research consistently links these fats with improved heart health, better cholesterol levels, reduced inflammation, and improved metabolic health when they replace higher intakes of saturated and trans fats.
There are two major categories:
Monounsaturated Fats (MUFA)
These fats are linked with:
Improved HDL (“good”) cholesterol
Better insulin sensitivity
Heart health support
Reduced inflammation markers
Foods High in Monounsaturated Fats include
Olive oil
Avocados
Avocado oil
Nuts (almonds, cashews, peanuts, pistachios)
Nut butters
Olives
Polyunsaturated Fats (PUFA)
These include omega-3 and omega-6 fatty acids.
Omega-3 fats are especially important because they support:
Brain health
Heart health
Recovery and inflammation balance
Eye health
Foods High in Omega-3 Fats include
Salmon
Sardines
Mackerel
Chia seeds
Flaxseed
Walnuts
Omega-6 fats are also essential, but many modern diets contain significantly more omega-6 than omega-3.
Foods high in omega-6 include:
Soybean oil
Corn oil
Processed snack foods
Fried foods
Many packaged foods
Omega-6 fats are not inherently harmful, but balance matters.
Is Saturated Fat Bad for You?
Saturated fat is one of the most debated topics in nutrition.
Current evidence suggests saturated fat itself is not necessarily harmful in moderate amounts for everyone, but consistently high intake, especially from highly processed foods, may contribute to elevated LDL cholesterol and increased cardiovascular risk in some individuals.
Foods High in Saturated Fat include:
Butter
Fatty cuts of red meat
Bacon and processed meats
Full-fat dairy
Cheese
Coconut oil
Fast food
Pastries and baked goods
The American Heart Association recommends limiting saturated fat to:
Less than 10% of total calories daily
Ideally closer to 5–6% for those with elevated cardiovascular risk
What Does That Actually Look Like?
For someone eating 2,000 calories daily:
10% of calories from saturated fat = about 22 grams/day
6% of calories from saturated fat = about 13 grams/day
That can add up quickly.
22g of Saturated Fat Looks like:
1 cheeseburger = ~10g
2 tablespoons butter = ~14g
1 slice pepperoni pizza = ~5g
Even a few convenience foods can easily push intake above recommended levels.
Trans Fats: The Unhealthy Fats to Avoid
Artificial trans fats are the type most strongly associated with negative health outcomes.
They are linked with:
Increased LDL cholesterol
Lower HDL cholesterol
Increased inflammation
Higher cardiovascular disease risk
Trans fats were historically common in:
Margarine
Shelf-stable baked goods
Fast food frying oils
Packaged snack foods
Many countries have significantly reduced or banned artificial trans fats, but small amounts may still appear in highly processed foods. In the United States:
Artificial trans fats are banned: The FDA prohibited adding partially hydrogenated oils (PHOs) to foods in 2018 (with some exceptions allowing for a phase-out until 2020.
Labeling loophole exists: While artificial trans fats are removed, small amounts of trans fat can still be present in processed foods. Regulations generally allow products to list "0 grams of trans fat" if they contain less than 0.5 grams per serving, which can still add up.
Look for:
“Partially hydrogenated oils” on ingredient labels and avoid these products.
How Much Fat Should You Eat?
Fat needs vary based on:
Body size
Activity level
Hormonal health
Medical history
Goals
General recommendations suggest:
20–35% of total daily calories from fat
What That Looks Like
For a 2,000 calorie diet:
Percentage of Calories Daily Fat Intake:
20% = ~44g
25% = ~56g
30% = ~67g
35% = ~78g
Because fat contains 9 calories per gram, it is very easy for portions to add up quickly.
What 10g of Fat Looks Like
1 tablespoon olive oil
2 tablespoons peanut butter
1/2 avocado
Small handful of nuts
2 eggs
What Happens if You Eat Too Much Fat?
Too much fat overall, regardless of source, can contribute to excess calorie intake because fats are calorie dense.
However, the type of fat matters greatly.
Potential Effects of Excess Saturated and Processed Fat Intake
Elevated LDL cholesterol
Increased cardiovascular disease risk
Increased inflammation in some individuals
Potential gastrointestinal discomfort
Calorie excess leading to weight gain over time
Potential Issues with Very Low Fat Intake
On the other end, chronically under-consuming fat may contribute to:
Hormonal disruption
Reduced satiety
Poor vitamin absorption
Hair/skin/nail changes
Lower testosterone and estrogen production
Poor recovery and energy levels
The goal is balance, not fear of fat.
Why Swapping Fat Sources Can Improve Health
One of the most beneficial nutrition changes is often not eating less fat, but replacing certain fat sources with more nutrient-dense options.
Examples of Helpful Swaps
Instead of:
Butter try Olive oil
Processed snack foods try Nuts or seeds
Fried fast food try Grilled proteins + avocado
Heavy cream sauces try Greek yogurt-based sauces
Processed meats try Salmon or lean protein
Small consistent swaps may improve:
Cholesterol markers
Satiety
Fiber intake
Inflammation balance
Cardiovascular health
Healthy Fat Takeaways
Fat is essential for health and should not be feared
Unsaturated fats are generally associated with better heart and metabolic health
Saturated fat is best consumed in moderation
Artificial trans fats should be minimized or avoided
Replacing processed fats with whole-food fat sources can improve overall health markers
Portion awareness matters because fat is calorie dense
Consistency and overall dietary patterns matter more than perfection
Nutrition rarely comes down to labeling foods as simply “good” or “bad.” Instead, focusing on balance, food quality, minimally processed foods, healthy fat sources, and sustainable habits tends to produce the best long-term outcomes for heart health, body composition, energy, and longevity.
Including more healthy fats like olive oil, avocado, nuts, seeds, and fatty fish while limiting excess processed and trans fats may support better overall health without unnecessary restriction.
References
American Heart Association. (n.d.). Dietary fats. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats
U.S. Department of Health and Human Services & U.S. Department of Agriculture. (2020–2025). Dietary Guidelines for Americans. https://www.dietaryguidelines.gov
World Health Organization. (2023). Trans fat elimination. https://www.who.int/news-room/fact-sheets/detail/trans-fat
Harvard T.H. Chan School of Public Health. (n.d.). Fats and cholesterol. The Nutrition Source. https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-and-cholesterol/
Mayo Clinic Staff. (n.d.). Dietary fats: Know which types to choose. Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/fat/art-20045550
Government Policy Reference (For the FDA ban and the exclusion of ruminant trans fats):
Food and Drug Administration. (2015). Final determination regarding partially hydrogenated oils. Federal Register, 80(116), 34650-34670. https://www.govinfo.gov/app/details/FR-2015-06-17/2015-14883 [1, 2, 3]
