Key Takeaways
Omega-3 fatty acids help support brain systems involved in mood, memory, and cognitive performance.Vitamins D and E require dietary fat for absorption, and deficiencies in these vitamins have been linked to mood and cognitive changes.Diets rich in unsaturated fats from foods like fish, olive oil, nuts, and seeds support brain health, while excess saturated fat may contribute to inflammation.
For years, fat has been framed as something to cut back on, but nutrition science has made one thing clear: healthy fats are essential, especially for your brain. When you consistently under-eat fat, the effects are not always dramatic at first, but eventually you’ll feel more sluggish and bogged down.
We asked nutrition and brain health experts to explain how a steady supply of healthy fats maintains brain health and what to expect when intake falls short. Here’s how much fat you really need and what to eat to get it.
Kristy Del Coro, MS, RDN, LDN, registered dietitian, culinary nutritionist, and spokesperson for avocados
Timothy Frie, DMS(c), MS, CNE, nutritional neuroscientist, behavioral neuronutritionist, and president of the National Academy of Neuronutrition
Marc Milstein, PhD, brain health researcher and author of The Age-Proof Brain
Why Fat Is So Important for Your Brain
In general, healthy fats help protect brain cells and keep them flexible. “Omega-3 fats are especially important for mood and cognitive performance,” says Marc Milstein, PhD, brain health researcher and author of The Age-Proof Brain. “Eating enough of the right fats can also help reduce inflammation, which plays a role in long-term brain health.”
More specifically, fats provide functional support for the brain and metabolic support for healthy digestion. “Healthy fats improve membrane fluidity, which impacts neurotransmitter signaling,” says Kristy Del Coro, MS, RDN, LDN, registered dietitian and culinary nutritionist. “Dietary fat also slows gastric emptying and improves blood sugar stability.” Fats work throughout the digestive system to help keep your energy levels steady. When your energy crashes, your mood and focus tend to dip as well.
Fats don’t just influence how your brain and stomach function—they are literally part of the brain’s physical structure. “Adequate fat intake is necessary for the structural integrity and communication systems of the brain,” says Timothy Frie, DMS(c), MS, CNE, nutritional neuroscientist and behavioral neuronutritionist. “Fatty acids form the lipid bilayer of neuronal membranes and regulate signaling pathways involved in mood, memory, cognition, emotional processing, and virtually everything happening in our brain.” In simpler terms, the fats you eat help build brain cells and support the signals they send to one another.
When experts talk about “healthy fats,” they are often referring to omega-3 fatty acids. These fats are found in foods like salmon, walnuts, flaxseeds, and chia seeds and help support brain cell structure and communication.
What Happens to Your Brain When You Don’t Eat Enough Fat
Over time, eating too little fat starts to affect how well your brain works day to day. “When dietary fat intake is too low, the brain lacks key lipid substrates required to maintain the structure and function of neurons,” Frie explains. “The human brain is roughly 60% fat by dry weight, and fatty acids are fundamental components of neuronal membranes, synapses, and myelin.”
Frie cites research that links low intake of essential fatty acids with poorer cognitive performance and greater risk of neurological and psychiatric conditions like depression and anxiety. In practical terms, a low-fat diet can lead to slower thinking, difficulty concentrating, and mental fatigue during everyday tasks.
Fat is also required for the absorption of fat-soluble vitamins (A, D, E, K), which are vital nutrients for your brain health and overall mood. “Vitamin D insufficiency is associated with depression and cognitive decline, so ensuring sufficient intake and proper absorption is very important for brain health,” Del Coro says. “Vitamin E also plays an important neuroprotective role as an antioxidant. Very low-fat diets put individuals at risk of disrupting hormone production and impacting nutrient absorption.”
Consequences of a High-Fat Diet
There is a caveat, though: it’s better to consume the right type and amount of fat because too much of the wrong type can have negative health effects as well. “Unfortunately, most people are consuming a high-fat diet dominated by saturated fats,” Frie says. “These diets increase neuroinflammation, impair insulin signaling in the brain, and weaken the blood–brain barrier. When this barrier becomes more permeable, inflammatory molecules can enter the brain more easily. Over time, this leads to poorer memory, impaired cognitive performance, and increased risk of neurodegenerative disease.”
How Much Fat to Consume Daily
Your brain and body need some fat to function. “Extremely low-fat diets (less than 20% of daily calories) are generally not recommended unless medically indicated,” Del Coro says. All the experts we spoke to agreed that most adults do well when about 20-35% of their daily calories come from fat. This translates to roughly 44–78 grams of fat per day in a standard 2,000-calorie diet, “though individual needs vary based on energy expenditure, health status, activity levels, and life stage,” Frie says.
Within that fat intake, regular consumption of omega-3 fatty acids is particularly important for the brain. “Most international nutrition and cardiovascular guidelines recommend about 250–500 milligrams per day of combined EPA and DHA for general health in adults,” Frie explains. For context, you can usually hit that target by consuming fatty fish two to three times per week. You can also get ALA omega-3s from plant sources like chia, flax, and walnuts.
“The key is choosing quality. Think salmon, olive oil, nuts, and seeds. It is not about eating more fat. It is about eating the right kinds,” Dr. Milstein says. Del Coro agrees that the quality of fat matters. “Limit saturated fat to less than 10% of total calories to reduce risk of cardiovascular disease,” she says, emphasizing unsaturated fats like nutrient-dense avocados.
