“Many people boil it down too simply and think they just need to eat a lot of fat and avoid carbs, but you can quickly eat an excessive amount of unhealthy fat on the keto diet,” says Kendra Whitmire, a nutritionist and dietitian with Sunshine Nutrition and Wellness in Laguna Beach, California, who practices functional and therapeutic nutrition. Keto’s leap onto the scene as a trendy diet is unique. “There’s never been a push for a high-fat diet before,” says Scott Keatley, RDN, of Keatley Medical Nutrition Therapy in New York City. As a result, research on choosing fats in the context of a high-fat diet is scarce. What’s clear is that sources of unsaturated fat are still recommended over saturated fats, says Keatley, even though both are considered keto-friendly. Saturated fats can raise your LDL, or “bad” cholesterol, while unsaturated fats can help lower cholesterol levels, per the American Heart Association (AHA). These unsaturated fats have been shown to be anti-inflammatory and heart-healthy. For example, in one study published in May 2020 in Cell, people following the ketogenic diet for eight weeks experienced a shift in the gut microbiome that reduced inflammation. (Per a past review, the gut microbiome is a collection of bacteria, microbes, and other components in the gut that may affect various bodily functions such as immunity, metabolism, and disease risk.) Researchers noted this is likely due to the ketone bodies produced during ketosis, a state in which you burn fat for your main source of energy instead of carbohydrates. That said, some of the research on the keto diet is conflicting. In a small study, published in June 2019 in the journal Obesity, switching to a keto diet was associated with higher inflammatory markers and cholesterol. More data needs to be accumulated to determine the effects that a keto diet, as well as the specific fats eaten, has on one’s health. You can eat higher-fat foods that contain protein, like bacon and sausage, but you’re better off adding fat to foods, as it’s easier to control, says Keatley. And bacon and sausages have a lot of calories, protein, and saturated fat. If you go off keto and continue eating these while adding carbs back in, it’s likely that you’ll regain any weight you may have lost. What’s more, consuming a lot of saturated fat, something that’s easy to do when choosing these types of foods, increases your levels of LDL (“bad”) cholesterol. LDL cholesterol boosts your risk of heart disease and stroke, according to the American Heart Association (AHA). Also know that while pure sources of fat, such as olive oil or coconut oil, contain 0 carbs, other sources, like nut butter or avocado, may be primarily fat but have carbohydrates that need to be counted in your total, too. Still, with research studies, like one published in January 2020 in the journal Circulation, showing that coconut oil consumption leads to an increase in LDL (“bad”) cholesterol levels (which raise your risk for heart disease and should be limited), it’s more important than ever to choose the right types of fat — even on a fat-friendly diet. A final guideline: Even if you’re on keto, portions of fat still matter, says Jill Gullotta, RDN, the founder of Jill Gullotta Nurition in White Plains, New York. “How much you specifically eat depends on your calorie needs and goals, but overconsuming fat can cause weight gain,” she says. After all, compared with protein and carbohydrates, fat is the more dense in calories. Also, considering that fat is your body’s main fuel source on a keto diet, she advises spreading out your fats evenly throughout the day. Many people on a keto diet count net carbs, which are total carbs minus fiber and sugar alcohols (since fiber goes through your system undigested). Both are taken into account here. Consider this your guide to cutting through the fat.
2. Olive Oil
“We know that when we have fats in our diet like MUFAs, they not only fill us up but keep cholesterol levels lower,” says Keatley. Olive oil is a staple of the heart-healthy Mediterranean diet and fits well into a keto diet, too; it’s great for light sautéing, using in dressings, or drizzling over cooked meats or vegetables as a finishing oil. One tablespoon (tbsp) offers 119 calories and 13.5 g of fat, only 2 g of which are saturated fat, per the USDA.
3. Avocado Oil
Like olive oil, avocado oil is rich in anti-inflammatory MUFAs, but one of the biggest benefits to using avocado oil is that it stands up to high-heat cooking. It has a smoke point of 520 degrees F, according to What’s Cooking America, meaning it’s ideal for stir frying and searing. Per the USDA, 1 tbsp of avocado oil has 124 calories, 14 g of fat (of which 1.6 g is saturated), and 0 g of carbohydrates.
4. Nuts and Nut Butter
Nuts and nut butters offer unsaturated fats, but they also contain carbs, so look at labels to calculate exactly what you’re getting, advises Whitmire. For example, 1 tbsp of almond butter offers 98 calories, 3.4 g of protein, 8.9 g of fat, 3 g of total carbs, and about 1.5 g of fiber (equaling about 1.5 g of net carbs), per the USDA. And if you opt for whole almonds, the USDA lists 164 calories, 6 g of protein, 14.1 g of fat, 6.1 g of carbohydrates, and about 3.5 g of fiber (totaling about 2.6 g of net carbs) per 1 ounce (oz) of almonds (around 23 nuts). Choose a nut butter labeled without added sugar, to ensure you’re not adding extra carbs to your diet.
5. Chia Seeds and Flaxseed
Whitmire recommends these seeds because they both offer omega-3 fatty acids. “Getting more of these fats will improve the ratio of omega-6s to omega-3s you consume, which some research suggests optimizes health,” she says. American diets tend to be higher in omega-6s than omega-3s, as Mount Sinai, points out, but it’s important to strike a balance. For example, a past article cited research that linked consuming more omega-3s and fewer omega-6s led to a lower risk of insulin resistance — the hallmark of type 2 diabetes — and obesity, among other protective health benefits. The USDA says 1 oz of chia seeds has 138 calories, 4.7 g of protein, 8.7 g of fat, 11.9 g of carbs, and a whopping 9.8 g of fiber (so only 2.1 net carbs). And 1 tbsp of ground flaxseed has 37 calories, 1.3 g of protein, 3 g of fat, 2 g of carbs, and 1.9 g of fiber (basically 0 net carbs), per the USDA. Just be sure to buy ground flaxseed so your body can absorb the omega-3s.
6. Fatty Fish
If you’re not fitting fish into your keto diet, now is the time to start. The AHA recommends consuming fish at least twice per week, emphasizing fatty fish, such as salmon, sardines, mackerel, and bluefin tuna, which are packed with heart-healthy omega-3 fatty acids. Research shows that consuming 20 g of fish per day (just under 1 oz) is associated with a 4 percent lower risk of heart disease and heart disease-related mortality, per a meta-analysis published in Nutrients in August 2020. However, fewer than 1 in 5 people eat the recommended amount of fish per week, according to the Harvard T.H. Chan School of Public Health. A 3-oz serving of salmon (about the size of a checkbook, per University of Rochester Medical Center [PDF]) offers 118 calories, 19.9 g protein, 3.7 g fat, and 0 g carbohydrates, according to the USDA.
2. Cream
Adding heavy cream or half-and-half to your coffee is one way to get an additional source of fat into your day, says Keatley. Just keep in mind that it is a source of saturated fat — and given the small serving size, it’s easy to go overboard. A serving size, or 1 tbsp of heavy cream, has 51 calories and 5 g of fat (3.5 g of saturated fat), and it is just shy of 0.5 g of carbs, per the USDA.
3. Coconut Oil
Trendy coconut oil has been credited as a cure-all for health ills — and you may think you should consume as much as you want while following the keto diet. But that’s not exactly the case. “There’s a controversy with coconut oil because of its high levels of saturated fats, which are the ones that clog arteries,” says Keene. But some argue that coconut oil is different, Keene adds, since its fat is made up of medium-chain triglycerides (fatty acids that the body metabolizes more quickly and are less likely to get stored by the body as fat). Eat healthier unsaturated sources of fat first, and moderate amounts of saturated sources like coconut oil, advises Keene. And if you do choose to consume coconut oil, keep in mind that 1 tbsp offers 104 calories, 11.5 g of fat (9.6 g of which is saturated), and 0 g carbs, per the USDA.
4. Butter
“Eating a significant amount of butter has some of the worst effects on your health compared with other fats,” says Keatley. It’s high in saturated fat and cholesterol, meaning it can increase your risk of heart disease, per the Cleveland Clinic. It’s okay to use butter in your fat rotation but best not to make it your go-to fat; instead, opt for unsaturated sources. 1 tbsp of butter has 102 calories, 11.5 g of fat (7.3 g of which is saturated), and 0 carbohydrates, per the USDA.
5. Whole Milk
Whole milk does have a good amount of fat — 8 g per cup, per the USDA — but that fat comes alongside plenty of net carbohydrates, 11.7 g to be exact. A tablespoon of whole milk in your scrambled eggs may not make much of a difference to your carb goals, but consuming a half or full cup will (and will likely require advanced planning to ensure you stay within your limits). Milk does offer a source of calcium and vitamin D, as well as other minerals that are good for your bones, so make sure you’re consuming other sources of these nutrients via lower-carb options, such as fortified plant milks.
6. Red Meat
Because meat is naturally carb-free, it’s a popular choice for people following the keto diet. But not all types of meat are created equal. The AHA advises limiting the amount of fatty meats like beef, lamb, and pork in your diet, since they’re high in saturated fat. (For example, a 4 oz serving of ground beef offers 14.4 g of fat, of which 6 g is saturated, per the USDA.) Instead, opt for leaner meats, like skinless chicken and turkey — or ask your butcher, grocer, server, or chef to help you choose the leanest cuts of beef, as Mayo Clinic advises.
