6 Sneaky Signs You Might Not Be Eating Enough Fat

The low-fat trends of the '80s and '90s have gone the way of perms and pleated pants—it's no longer the norm (and thank goodness for that, right?). Yet some Americans are still under the assumption that eating fat “makes” us gain weight, potentially resulting in underconsumption of this key macro. For healthy adults, the 2020-2025 Dietary Guidelines for Americans recommends 20% to 35% of daily calories should come from fat, with most fats coming from sources of polyunsaturated and monounsaturated fatty acids, such as fish, nuts and vegetable oils.

So, what does that balance look like in terms of what you see on the nutrition label? For people who are following a 2,000-calorie diet, the minimum amount of fat you should eat is around 44 grams per day, which is 20% of your total calories. Science has shown—and the dietitians we spoke to agree—eating too little fat, especially certain “healthy” fats like omega-3 fatty acids, can negatively affect your brain and body. Read on for how to tell if you’re not meeting your needs.

1. You're Always Hungry 

One of the many benefits of fat: It's super-satisfying. "The body uses up carbs and protein very quickly. Fat, on the other hand, really slows down the digestion of food and provides substantial calories," shared Ashley Reaver, RD. 

If you're ravenous again shortly after meals, try adding an extra fat source, such as a hard-boiled egg (yolk included) with your breakfast of fruit and cereal or a schmear of guacamole on your turkey sandwich at lunch.

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2. You Frequently Feel Fatigued 

Your body needs fuel to fire on all cylinders. "Low intake of fat will likely lead to a low intake of overall calories," Reaver says. "Fat contains 9 calories per gram, significantly more than protein and carbs, which each contain 4 calories per gram. Limiting fat intake will also significantly limit overall calorie intake." The end result: You feel super-sluggish.

3. Your Joints Ache 

Omega-3 fatty acids—found in salmon, walnuts, tuna, flax seed and more—help maintain the structural integrity of every cell from head to toe, Reaver explains.

Without sufficient omega-3 fatty acids, joints may become stiff and inflamed, leading to aches and pains that make daily activities uncomfortable. Beyond their anti-inflammatory benefits, these fats also contribute to the production of lubricating fluids around joints, promoting smooth movement. Incorporating sources like chia seeds, avocados and olive oil can further ensure your body gets the healthy fats it needs to stay balanced for less joint pain.

4. You're Catching More Colds Than Usual 

Your seemingly constant sniffles might be related to inadequate sustenance, rather than poor hand hygiene or sheer bad luck.

"Omega-3 fatty acids are also closely tied to inflammation and immune health. A low intake of fats—and therefore a low intake of omega-3s—can result in a weaker-than-usual immune system, leaving you susceptible to frequent bouts of the common cold or upper respiratory infections," Reaver says.

5. Your Skin Is Dry 

The saying "you are what you eat" does have some truth to it, and if you don't eat a lot of oil, your body may not have much to spare to maintain soft and supple skin.

"One of the biggest signs that you're not eating enough fat is dry skin, which can speed up the appearance of aging," Bonnie Taub-Dix, RD says. "Fat also helps your body absorb fat-soluble vitamins which can help you glow from the inside out."

6. Your Brain Feels Foggy 

Not eating enough fat may negatively affect brain function, potentially leading to feelings of mental fog and reduced concentration. "Omega-3 fatty acids are critical for maintaining the structural integrity of brain cells, too. If you are feeling 'off' mentally, this may be an indication that your fat intake is too low. Research also supports that omega-3 intake is linked to overall mood," Reaver says.

The Bottom Line

If you're experiencing any of the above symptoms, take a look at what you're eating at each meal to see if the culprit may be eating too little fat (or carbs or protein). Rather than going from one extreme (low- or no-fat diets) to the other extreme (high-fat diets, like keto), following a balanced diet that includes healthy amounts of all foods, is the golden ticket.

Understanding the difference between healthy and unhealthy fats is also key. Healthy fats, like those in nuts, seeds, fatty fish and plant-based oils, deliver vital nutrients that support your overall well-being. However, trans fats and excessive saturated fats may lead to inflammation and raise the risk of chronic diseases.