Few nutrients have sparked as much debate as dietary fat. The nutrition advice many of us grew up with, along with decades of food marketing, has shaped how we think about fat more deeply than we may expect.
From low-fat labels to the emphasis on fat-rich foods, our perception of fat continues to change. But one thing remains true: not all fats affect the brain the same way. In this article, we’ll break down why the brain depends on fat, which types are most closely linked to brain health, and why it’s more complicated than “good” versus “bad.”
Why Your Brain Needs Fat
Your brain is one of the fattiest organs in your body, making up about 60% of its dry weight (meaning, after you’ve subtracted the water in the brain).1 Fat doesn't just serve as a place to store energy; it’s also essential to helping the brain function properly.
Fats help form the membranes surrounding brain cells, support myelin production (for nerve fiber insulation and transmission), and help neurons communicate. Together, these roles support learning, memory, attention, and healthy inflammatory responses.
Although the brain depends on fat, different types of fat play different roles in supporting brain health. Some are consistently associated with better brain health and healthy aging, while others have been linked to poorer health outcomes. Also, dietary context matters (we’ll get to that later). To understand these differences, we begin with the fats that have some of the strongest evidence behind them.
The Fats Most Commonly Linked to Better Brain Health
Omega-3 Fatty Acids
Omega-3 fatty acids are some of the most well-studied fats for brain health. They are a type of polyunsaturated fat and come in three main forms: DHA (docosahexaenoic acid), EPA (eicosapentaenoic acid), and ALA (alpha-linolenic acid).
Unsaturated fats get their name from their chemical structure. Unlike saturated fats, which have a straight shape, unsaturated fats contain one or more bends (or kinks) in their structure. Those bends prevent them from packing tightly together, which is why they're typically liquid at room temperature. Omega-3s are a type of polyunsaturated fat, meaning they have multiple bends, while olive oil and avocado oil are mostly monounsaturated fats, meaning they have just one.
While ALA is found in plant foods like walnuts, flaxseed, chia seeds, and pecans, DHA and EPA are primarily found in fatty fish such as salmon, sardines, trout, and mackerel. Although the body can convert some ALA into DHA and EPA, the conversion rate is relatively low, making seafood one of the richest dietary sources of DHA and EPA, the two omega-3’s most directly associated with brain-supportive roles.
DHA has received the most attention for brain health. It is a major structural component of brain cell membranes, helping neurons communicate efficiently while supporting learning, memory, and healthy inflammatory responses. EPA also helps regulate inflammation, together creating an environment that supports healthy brain function throughout life.2
The strongest evidence for omega-3s comes from studies of dietary intake, particularly in people who regularly consume fish as part of an overall healthy eating pattern. Studies of omega-3 supplementation have produced more mixed results, some indicating benefits and others not, leading researchers to question whether their study methods need to be improved to get a clearer result. Differences in dose, formulation, study duration, and when supplementation begins can all influence outcomes. In a recent better-controlled study, a 2023 investigation and review found that higher omega-3 intake from both diet and supplements was associated with a lower risk of dementia and cognitive decline.3
If you'd like a deeper dive into the differences between DHA, EPA, and ALA, check out our previous article, Understanding Omega-3 Fats and Their Many Benefits.
Monounsaturated Fats
Along with omega-3s, monounsaturated fats (also referred to as omega-9 fatty acids) make up the two major types of unsaturated fats most consistently associated with long-term brain health. Monounsaturated fat food sources include olive oil, avocados, and many nuts.
Extra virgin olive oil (EVOO) is a staple of brain-healthy diets, and its benefits go beyond its fat content. It also contains naturally occurring plant compounds called polyphenols, which have antioxidant and anti-inflammatory properties that support vascular health and reduce oxidative stress, both of which are important for maintaining long-term brain function.
Read more on the Brain Health Benefits of Polyphenol-Rich Olive Oil.
People who more closely follow Mediterranean-style eating patterns tend to experience slower cognitive decline, suggesting olive oil works best as part of an overall healthy diet rather than as a standalone superfood. Other sources of monounsaturated fats include avocados (and avocado oil), pumpkin seeds, and a variety of nuts, such as almonds, hazelnuts, and cashews.4
Choosing an Olive Oil That Supports Brain Health
When choosing an extra virgin olive oil, know that quality matters. Factors such as the olive variety (or “cultivar”), harvest timing, processing methods, weather and terrain, and polyphenol content can all influence the final product and its health benefits. Brain Health Kitchen Extra Virgin Olive Oil was made with this in mind, emphasizing the mind-nourishing properties of high-quality EVOO so you get more from your meals.
Are There “Bad” Fats?
Trans Fats
Among the different types of dietary fat, trans fats are one of the few with consistent evidence against them. Artificial trans fats are created through a process called hydrogenation, which was originally used to improve texture and extend the shelf life of processed foods.
During hydrogenation, hydrogen atoms are added to unsaturated fats, straightening their structure and making them more solid and shelf-stable. However, this process also creates trans fats.
Research has consistently linked trans fats to inflammation, cardiovascular disease, and poorer cognitive health. Because heart and brain health are closely connected, higher trans-fat intake has also been associated with an increased risk of cognitive impairment and dementia.5
Artificial trans fats were once a staple of the Standard American Diet, but they are being largely removed from the food supply in many countries.
That’s not to say they are completely gone, though. So, here’s what to look for when food shopping:
-
Check ingredient lists for the words "partially hydrogenated oil." If you see them, the product contains artificial trans fats.
-
Be watchful of foods like margarine and vegetable shortening, which have historically been common sources, although many manufacturers have reformulated their products.
-
Don’t rely on a “0g Trans Fat” claim alone, since the FDA allows products to make this claim even when small amounts are present — the ingredient list is often more informative.
Saturated Fats
Saturated fats are a little more complicated.
Saturated fats have a different chemical structure than unsaturated fats. Think of them like straight strings that stack neatly together, allowing them to pack tightly into a solid at room temperature. That's why foods like butter, lard, coconut oil, and the fat found in many meats are solid, while oils like olive oil remain liquid.
These types of fats have a well-established relationship with higher LDL (“bad”) cholesterol and cardiovascular disease, which is why it’s recommended to limit saturated fat intake, especially given there are so many potential sources in our diet and food system (think meats, burgers, ice cream, fast food, etc.). Because the brain relies on healthy blood flow, reducing saturated fats can be a protective measure for cognitive health, too.
However, recent research is exploring the idea that not all saturated fat-containing foods have the same effects. For example, saturated fat consumed in yogurt or cheese may not affect health in the same way as saturated fat from processed meats. One reason for this may be what's known as the food matrix — the idea that a food's health effects are influenced not only by its individual nutrients, but by how those nutrients interact within the food itself. In other words, the whole can be greater than the sum of its parts.6
As a result, researchers are increasingly looking beyond individual nutrients and instead studying the foods and overall eating patterns they come from. The American Heart Association highlights the importance of following eating patterns with foods rich in unsaturated fats — think fish, extra virgin olive oil, nuts, and seeds — while limiting foods high in saturated fat, rather than focusing on eliminating fat altogether.7
Summary Table: A Quick Guide to Dietary Fats
How Healthy Fats Fit into Your Diet
We don't eat fats in isolation — we eat foods and meals. Context matters. That's why researchers are beginning to focus more on dietary patterns than individual nutrients. The Mediterranean, MIND, and DASH diets naturally emphasize the same fats we’ve covered throughout this article and are consistently linked to brain health. Here’s what these eating patterns have in common: they encourage foods rich in unsaturated fats, including fatty fish, olive oil, nuts, and seeds, alongside vegetables, fruits, legumes, whole grains, and other minimally processed foods. Healthy fats aren't a separate strategy for brain health — they're a defining feature of the eating patterns with the strongest evidence behind them.
Never Miss a Day of Brain Support
A healthy diet remains the foundation of brain health, but eating enough brain-supporting foods every day isn’t always easy. RELEVATE was designed to complement a healthy diet by providing 17 nutrients commonly found in Mediterranean and MIND-style eating patterns. When paired with a healthy lifestyle, it can help support cognitive function, everyday energy, and healthy aging.
So, Should You Eat Fat?
The conversation around dietary fat has changed dramatically over the years, but one message has become especially clear: the right fats deserve a place on your plate. And choosing foods naturally rich in omega-3s and monounsaturated fats is one of the simplest ways to support your brain today while investing in its health for years to come.
References
1. Chang, C.-Y., Ke, D.-S. & Chen, J.-Y. Essential fatty acids and human brain. Acta Neurol. Taiwan. 18, 231–41 (2009).
2. Welty, F. K. Omega-3 fatty acids and cognitive function. Curr. Opin. Lipidol. 34, 12–21 (2023).
3. Wei, B.-Z., Li, L., Dong, C.-W., Tan, C.-C. & Xu, W. The Relationship of Omega-3 Fatty Acids with Dementia and Cognitive Decline: Evidence from Prospective Cohort Studies of Supplementation, Dietary Intake, and Blood Markers. Am. J. Clin. Nutr. 117, 1096–1109 (2023).
4. Valls-Pedret, C. et al. Mediterranean Diet and Age-Related Cognitive Decline. JAMA Intern. Med. 175, 1094 (2015).
5. Scarmeas, N., Anastasiou, C. A. & Yannakoulia, M. Nutrition and prevention of cognitive impairment. Lancet Neurol. 17, 1006–1015 (2018).
6. Wu, M. et al. Association between dietary fat intake and long-term risk of dementia: a prospective cohort study. Am. J. Clin. Nutr. 122, 1725–1734 (2025).
7. Lichtenstein, A. H. et al. 2021 Dietary Guidance to Improve Cardiovascular Health: A Scientific Statement From the American Heart Association. Circulation 144, (2021).