Your Instagram feed is filled with perfectly arranged, rainbow-colored smoothie bowls and matcha lattes—that’s nothing new. But you’ve probably noticed a formerly vilified ingredient is now the star of the show. Traditional dietary recommendations be damned; according to practically every wellness influencer out there, high fat is in.
From that food blogger using an entire avocado as a questionably designed sandwich bun to your fitness instructor mainlining coconut oil with her salmon fillet, it seems that as long as it’s hashtagged #goodfat, consuming a million grams of fat is healthy for you.
"I think this is, in part, a reaction to the failings of the low-fat diet craze of the 70s and 80s," says Matt Priven, a Boston-based registered dietitian nutritionist. "Those diets really missed the mark and did not help people achieve their health goals."
The Problem With Low Fat
That craze is still alive and well in grocery stores, with low-fat and fat-free yogurt, cheese, and frozen foods filling the dairy cases and aisles. One of the issues with low-fat diets is fat tends to give food flavor (and often texture), so to counter the lost taste, companies tend to add boatloads of sugar to make the food palatable again, creating a different set of problems.
The most recent Dietary Guidelines for Americans say fat should account for 20 to 35 percent of your total daily calories. Any lower than that can lead to deficiencies in vitamins A, D, E, and K, "as well as some phytonutrients, which require dietary fat for proper absorption," Priven says.
What Priven is referring to is bioavailability, or how much of a nutrient is able to enter the body. There are various ways we can increase nutrient availability—for instance, soaking nuts in water allows you to absorb more of their nutrients, rather than letting them pass through your system unused.
Additionally, when you enjoy a big salad filled with delicious, fresh vegetables in every color of the rainbow with low-fat dressing, it does a disservice to your body. Fat unlocks more of the phytonutrients Priven refers to—such as lutein in green peppers and lycopene in tomatoes—which are both powerful antioxidants with cancer-fighting properties. Lutein, lycopene, and their oxidative metabolites in chemoprevention of cancer. Khachik F, Beecher GR, Smith JC. Journal of cellular biochemistry. Supplement, 1996, Feb.;22():0733-1959. Get the biggest bang for your buck and enhance the availability of nutrients with a full-fat dressing—or, better yet, make your own without all the preservatives and ingredients you can’t pronounce.
The tired diet cliché of always being famished partly stems from these low-fat regimens—a lot of us can relate to still feeling hungry after eating a salad dressed in reduced-fat vinaigrette. On top of helping us absorb more nutrients, fat helps keep us satiated; it contains 9 calories per gram compared to the 4 grams each we get from carbs and protein, and its density helps keep us fuller longer.
So in this regard, it’s not entirely a bad thing that social media influencers are touting a higher-fat diet. The type of fat is what matters—but there are competing studies on the subject.
Has Saturated Fat Been Liberated?
Dietary guidelines recommend monounsaturated and polyunsaturated fats such as olive oil, nuts, and avocados, as well as fatty fish, flaxseeds, and chia seeds for their omega-3 content, an essential fatty acid proven to benefit heart health. Omega-3 fatty acids: role in cardiovascular health and disease. Engler MM, Engler MB. The Journal of cardiovascular nursing, 2006, Mar.;21(1):0889-4655. These fats have been generally considered preferable to saturated fat. However, recent studies brought into question the guidelines that say to keep saturated fat to a maximum of 10 percent of your total fat calories.
For example, a study published in late 2016 in the American Journal of Clinical Nutrition found a high intake of saturated fat did not heighten the risk of cardiovascular disease in its participants and, in fact, increased levels of their “good” cholesterol (known as HDL cholesterol; LDL is the one you want to decrease). Visceral adiposity and metabolic syndrome after very high-fat and low-fat isocaloric diets: a randomized controlled trial. Veum VL, Laupsa-Borge J, Eng Ø. The American journal of clinical nutrition, 2016, Nov.;105(1):1938-3207. Researchers attributed this finding to the high quality of foods participants consumed.
Does that mean it’s time to guzzle $20 worth of coconut oil in one sitting? Not quite. We often don’t get the full picture of the studies reported in the news, and neither do social media influencers.
David L. Katz, M.D., the founding director of Yale University’s Yale-Griffin Prevention Research Center and chief medical officer of digital health company FareWell, "emphatically" disagrees with the study's findings.
"The evidence is now overwhelming and clear that even with high HDL, people on [high-saturated-fat] diets have more, not less, heart disease," he says. "The weight of evidence clearly now indicates that LDL levels are the best predictors of cardiovascular risk, and those too go up with saturated fat intake."
So… how about a high-fat diet with mostly unsaturated fats instead? Katz says that aside from the saturated-fat argument, "total fat level in the diet is rather unimportant provided that the sources of fat are wholesome."
But before you douse that sliced avocado in half a bottle of avocado oil and top it off with a little fried avocado, keep reading.
The Ketogenic Craze
The ketogenic diet, which you’ve probably heard about via Instagram, is a low-carb, high-fat regimen. Plenty of influencers are touting the benefits of this regimen; they primarily report significant weight loss, which is attributed to the diet's low-carb, high-fat meals and snacks with names like "fat bombs."
Long story short, this diet is designed to put the body in a metabolic state known as ketosis, during which the liver breaks down fat to produce ketones that are used as energy. Originally intended to treat epilepsy patients, many have been using it as a quick way to burn fat and lose weight.
If total fat is irrelevant as long as it's from good sources, can we go keto crazy? Not so fast.
Many others in the field prefer a more moderate approach, including Priven, who believes balance is key.
“When we [increase] intake of a certain food group, the collateral effect is usually a decreased intake of another food group,” he says, meaning high fat in our diet leaves less room for other nutritious foods. “Ultimately, the ketogenic diet is still a diet. It’s highly unsustainable and potentially problematic from a health standpoint; staying in ketosis means avoiding tons of healthy foods like fruit, beans/legumes, grains, and many vegetables.”
With so many messages coming at us every day from bloggers, Insta-famous foodies, nutrition headlines, etc., how do we know what to eat if what they’re telling us isn’t always accurate?
Priven recommends balanced eating and working on sustainable habits. So eat that avocado bun but not for every meal. Toss some butter in your sauté pan—but the grass-fed kind, not trans-fat margarine. Get beefy on taco night but opt for hormone-free meat. Ultimately, it comes down to something you probably knew all along: Use the good stuff and use it in moderation.
Kristen Ciccolini is a freelance food writer and plant-based nutrition coach based in Boston. She is focused on nutrition education and teaches busy women how to incorporate healthy habits into their everyday cooking. When she's not nerding out over food, you can find her upside down in a yoga class or right side up at a rock show. Follow her on Twitter @kciccolini.