The ketogenic diet, characterized by its very low carbohydrate and high-fat content, has garnered significant attention for its potential benefits in weight loss, blood sugar management, and various other health improvements. A cornerstone of this dietary approach is understanding how much fat to consume to achieve and maintain ketosis, the metabolic state where the body primarily uses fat for fuel. This comprehensive guide delves into the nuances of fat intake on a ketogenic diet, providing insights into the best types of fats to include, those to moderate, and how to tailor your fat consumption to your individual needs and goals.
Introduction to the Ketogenic Diet
The ketogenic diet is a very low-carb, high-fat diet that shares many similarities with the Atkins and low-carb diets. It involves drastically reducing carbohydrate intake and replacing it with fat. This reduction in carbs puts your body into a metabolic state called ketosis. When this happens, your body becomes incredibly efficient at burning fat for energy. It also turns fat into ketones in the liver, which can supply energy for the brain. Ketogenic diets can cause significant reductions in blood sugar and insulin levels. This, along with the increased ketones, has some health benefits.
There are several versions of the ketogenic diet, and what you eat depends on the type. They include the standard ketogenic diet (SKD), which typically contains 70% fat, 20% protein, and only 10% carbs; the cyclical ketogenic diet (CKD), which involves periods of higher carb refeeds; the targeted ketogenic diet (TKD), which allows you to add carbs around workouts; and the high protein ketogenic diet, which includes more protein. However, only the standard and high protein ketogenic diets have been studied extensively. Cyclical or targeted ketogenic diets are more advanced methods and primarily used by bodybuilders or athletes.
Understanding Ketosis
Ketosis is a metabolic state in which your body uses fat for fuel instead of carbs. It occurs when you significantly reduce your consumption of carbohydrates, limiting your body’s supply of glucose (sugar), which is the main source of energy for the cells. Following a ketogenic diet is the most effective way to enter ketosis. Generally, this involves limiting carb consumption to around 20 to 50 grams per day and filling up on fats, such as meat, fish, eggs, nuts, and healthy oils. It’s also important to moderate your protein consumption because protein can be converted into glucose if consumed in high amounts, which may slow your transition into ketosis.
Why Fat Matters on Keto
Dietary fat is the cornerstone of the ketogenic diet. When given the choice, your body will always choose to burn glucose (from carbs and sugar) for energy. Once your glycogen stores are used up, your body starts burning body fat instead. Studies show that eating a high-fat, low-carb diet like keto can help reduce your risk of heart disease, jumpstart weight loss, and reduce inflammation. One of the biggest mistakes people make when starting the keto diet is not getting enough fat. The keto diet is different than other low-carb diets (like Atkins or the Mediterranean diet, for example) in that keto is not a high-protein diet.
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Determining Your Ideal Fat Intake
Determining the right amount of fat for a ketogenic diet depends on personal factors, including age, gender, activity level, and health goals. While there’s no universal answer, there are some general guidelines that can serve as a starting point for most individuals embarking on a high-fat diet.
On a standard ketogenic diet, fat typically accounts for 60 to 80 percent of daily calorie intake. For someone consuming 2000 calories per day, this translates to a daily fat intake of 133 to 178 grams. This may seem like a high amount, especially when compared to conventional dietary recommendations. However, fat is very calorie-dense, providing around nine calories per gram.
Calculating Your Macronutrient Ratios
Understanding macronutrient ratios is crucial for successfully implementing a ketogenic diet. While the exact ratios can vary slightly depending on individual needs and health goals, there are some guidelines you can follow. A standard ketogenic diet typically follows a macronutrient distribution of around 60 to 80 percent of calories from fat, 20 to 25 percent from protein, and 5 to 10 percent from carbohydrates. These ratios help you achieve and maintain ketosis by focusing on fat as the primary source of calories. Many resources and tools are available to help you easily calculate your ideal macronutrient needs, such as a Keto Calculator, which offers a comprehensive breakdown of your ideal fat intake requirements.
Individualizing Your Fat Intake
The amount and type of fat you should eat depends on three different scenarios: if you have weight to lose, if you don’t have weight to lose, and/or if you’re increasing your carb target.
- Scenario 1: You Have Weight to Lose: If you want to lose weight, you need to use your own fat stores. If you didn’t get much fat at lunch, consider having a decaf coffee with a tablespoon of heavy cream. But don’t overdo it with extra fat just for fun, as that can hinder your weight loss. Try adding 1-2 tablespoons of fat per meal from sources like butter, cooking oils, heavy cream, or sour cream if your meal was light on fat. If you’re still hungry at dinner, add a bit more. Monitor your weight and work with your coach to find your sweet spot.
- Scenario 2: You Don’t Have Weight to Lose (Or You Are Maintaining Your Weight Loss): If you’re in ketosis and don’t have much weight to lose, or if you’ve reached your weight goal and want to maintain it, ensure you’re getting enough fat in your meals in order to meet your body’s energy needs since you won’t be providing much from your own fat stores. Add an extra pat of butter to your chicken thighs, pesto sauce on your salmon, or chimichurri on your steak. Use veggies as a vehicle for fat by sautéing in butter or cooking oil, topping with cheese, or dipping in lemon aioli. Fresh whipped cream with your berries? Go for it!
- Scenario 3: You’re Moderately Increasing Your Carb Intake: Some folks might be experimenting with increasing their carbohydrate intake to find their sustainable sweet spot. Maintaining a lower-carb lifestyle is still a priority, but maybe getting your ketones to 1.5 isn’t. That’s ok! However, this approach adds a layer of complexity. The more carbs you eat, the lower your fat intake should be to balance energy requirements. Additionally, if you increase your carbs enough, we’d suggest you focus more on unsaturated fats like olive oil, avocado oil, oils from fatty fish like salmon, nuts, seeds, and avocados. The health impact of eating a higher carb diet with a higher amount of saturated fat (fatty meats, cheese, sour cream, bacon) is not entirely clear. For that reason, if you’re not in ketosis, we recommend limiting your intake of saturated fat and focusing more on the unsaturated oils mentioned above.
Best Fats to Include in Your Keto Diet
Incorporating healthy fats into your diet, especially within a well-formulated ketogenic diet, can offer numerous health benefits. Here are some of the best fats to include:
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1. Avocados and Avocado Oil
Though technically a fruit, avocados offer a rich source of heart-healthy monounsaturated fatty acids (MUFAs). They’re also packed with fiber, which bolsters digestive health. Half of an avocado contains 114 calories, 1.3 grams (g) of protein, 10.5 g of fat, 6 g of total carbs, and 5 g of fiber (1 g of net carbs). Add avocados to a salad, smoothie, or breakfast plate to reap the benefits of this keto-friendly favorite. Avocado oil is also rich in anti-inflammatory MUFAs. One of its biggest benefits is that it stands up to high-heat cooking. Avocado oil has a smoke point of over 482 degrees F, making it ideal for stir-frying and searing. One tablespoon (tbsp) of avocado oil has 124 calories, 14 g of fat (1.6 g saturated fat), and 0 g of carbohydrates.
2. Olive Oil
Olive oil is a staple of the heart-healthy Mediterranean diet and fits well into a keto diet, too. It is also high in monounsaturated fats and works great for light sautéing, using in dressings, or drizzling over cooked meats or vegetables as a finishing oil. One tablespoon of olive oil offers 119 calories, 13.5 g of total fat, and only 2 g of saturated fat. Olive oil contains no carbs or fiber.
3. MCT Oil
MCT (medium-chain triglyceride) oil is a supplement made from medium-chain fatty acids. These types of fat are more easily digested than the long-chain fatty acids found in most other foods. MCTs are rapidly absorbed and converted into ketones by the liver, making them especially useful for people on a keto diet. Some people take MCT oil by itself. But you can also add 1 or 2 teaspoons to low-carb smoothies for an extra fat boost or mix with olive oil, vinegar, and herbs for a keto-friendly vinaigrette.
4. Nuts and Nut Butters
Nuts and nut butters can be a good source of unsaturated fats. However, many also contain carbs, so be sure to look at labels to know exactly what you’re getting. 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 (about 1.5 g net carbs). One ounce (oz) of whole almonds (about 23 nuts) provides 164 calories, 6 g of protein, 14.1 g of fat, 6.1 g of carbohydrates, and about 3.5 g of fiber (2.6 g net carbs). When choosing nut butters, look for those labeled “without added sugar” to ensure you’re not adding extra carbs to your diet.
5. Chia Seeds and Flaxseeds
Chia seeds and flaxseeds are high in 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. One ounce 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 (2.1 net carbs). One tablespoon 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 (0 net carbs). Choose ground flaxseed instead of whole to allow your body to better absorb the omega-3s.
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6. Fatty Fish
The American Heart Association recommends consuming fish at least twice per week, emphasizing fatty fish, which are packed with heart-healthy omega-3 fatty acids. Examples include salmon, sardines, mackerel, and bluefin tuna. A 3 oz serving of salmon offers 118 calories, 19.9 g protein, 3.7 g fat, and 0 g carbohydrates.
7. Full-Fat Greek Yogurt
Unsweetened, full-fat Greek yogurt does have some carbs, but the higher fat content can make it a healthy option for a keto diet. A 5.3 oz serving provides approximately 6 g of fat, 13 g of protein, and 6 g of carbs. Use Greek yogurt to make a dip by mixing in herbs and spices, or create a sweet treat by adding nuts, seeds, coconut, and cacao nibs.
8. Whole Eggs
Eggs are nutritious, high in protein and fat, and have zero carbs. Egg yolks are rich in B vitamins and the potent antioxidants lutein and zeaxanthin, which support eye health. A single large egg packs about 5 g of fat, 7 g of protein, 0 carbs, and 80 calories. Eggs are also versatile. Scramble them with low-carb veggies, poach or fry them with sliced avocado, or mix a hard-boiled egg with mayonnaise. Hard-boiled eggs also make the perfect grab-and-go snack.
9. Hemp Hearts
Hemp hearts are the inside part of hemp seeds, without the shell. They are one of the few plant-based protein sources that provide all nine essential amino acids. On top of that, they’re loaded with key nutrients like vitamin E, calcium, iron, and potassium. Hemp hearts are also high in healthy fat. One tablespoon of hemp hearts provides 5 g of fat, making them a perfect choice for high-fat diets. With a mild taste and a texture a lot like sesame seeds, hemp hearts are easy to work into all kinds of dishes. Try sprinkling them over yogurt, salads, or roasted veggies; blending them into smoothies or soups; or mixing them into energy bites. They’re also great stirred into sauces and dressings.
10. Cacao Nibs
Cacao nibs are a form of unsweetened, unprocessed raw chocolate. Just 1 oz provides about 12 g of fat and a whopping 9 g of fiber. Dark chocolate is also a great source of polyphenols. Polyphenols are plant compounds known for their powerful anti-inflammatory properties, which may help support the growth of healthy gut bacteria. Toss cacao nibs into keto-friendly smoothies, energy bites, or trail mix for a crunchy boost. Got a sweet tooth? Try making keto hot chocolate by melting cacao nibs in unsweetened coconut milk on the stove. Then stir in your go-to keto-friendly sweetener like stevia or monk fruit.
Fats to Eat in Moderation
Saturated fats can also be great to incorporate into your keto plan, but only in small amounts. Consuming foods high in saturated fat can increase your LDL cholesterol levels, the kind that boosts your risk of heart disease and stroke.
1. Butter
Butter is high in saturated fat and cholesterol, meaning it can increase your risk of heart disease. It’s still okay to use butter in your fat rotation, but it’s best not to make it your go-to fat. One tablespoon of salted butter has 102 calories, 11.5 g of total fat, 7.3 g of saturated fat, and 0 carbohydrates. Roast or sauté vegetables in butter or spread it on keto-friendly muffins, waffles, or pancakes. Rub butter over a whole chicken before roasting to achieve perfectly crispy skin.
2. Cheese
Cheese can be a good high-fat, low-carb, and high-protein option for keto dieters. But it’s best to be mindful of how much you’re eating. While individual cheeses have different nutritional profiles, their overall high saturated fat content qualifies them as a food to limit. Also, keep in mind that some cheeses are more keto-friendly than others. Enjoy cheese chunks or slices with fresh vegetable sticks, melt it over roasted or steamed vegetables, or make a Greek salad with crumbled feta cheese.
3. Cream
Adding heavy cream or half-and-half to your coffee is one way to get an additional source of fat into your day. Just keep in mind that cream is a source of saturated fat, and given the large amount packed into a small serving size, it’s easy to go overboard. A 1 tbsp serving size of heavy cream has 51 calories, 5 g of fat (3.5 g of saturated fat), and it is just shy of 0.5 g of carbs.
4. Coconut Oil
Despite coconut oil being 100 percent keto-friendly, it can be high in saturated fats. A higher consumption of saturated fats can lead to heart disease. If given the option, it's better to choose avocado or olive oil as a good source of unsaturated fats. If you do choose to consume coconut oil, keep in mind that 1 tbsp offers 104 calories, 11.5 g of total fat, 9.6 g of saturated fat, and 0 g carbs.
5. Whole Milk
Whole milk is a good source of fat (8 g per cup), but that fat comes along with 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 in your carb goals. But consuming a half- or full cup will, and will likely require some planning to help you stay within your limits. Whole milk offers calcium and vitamin D, as well as other minerals that are good for your bones. To help limit your carbs, make sure you’re also 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 American Heart Association advises limiting the amount of fatty meats like beef, lamb, and pork in your diet, since they’re high in saturated fat. Instead, opt for leaner meats, like skinless chicken and turkey. Alternatively, ask your butcher, grocer, server, or chef to help you choose the leanest cuts of beef. Red meat can be a great source of fats and protein in a keto diet, rich in B vitamins, zinc, and protein.
Fats to Avoid
Most trans fats in the Standard American diet come from hydrogenation, which turns oils into solids and prevents them from going rancid. This is how manufacturers used to make margarine. However, in 2015 the Food and Drug Administration (FDA) banned manufacturers from adding trans fats to food products because they have no health benefits and raise levels of low-density lipoprotein (LDL), or bad, cholesterol in the blood while lowering good cholesterol. This can increase the risk of heart disease. Trans fats are often found in fried foods, snacks, such as microwave popcorn, frozen pizzas, baked goods, and ready-to-use frosting.
Incorporating Healthy Fats into Your Keto Diet
Incorporating healthy fats into a ketogenic diet doesn’t have to be complicated. There are many whole foods naturally high in fat that can easily be integrated into your daily meals. Avocados, rich in monounsaturated fats, can be added to salads and smoothies or turned into a delicious keto-friendly pudding. Extra virgin olive oil is perfect for salad dressings and drizzling over roasted vegetables. Fatty fish, such as salmon and sardines, are loaded with omega-3 fatty acids and can be used to make various tasty dishes, including Keto Salmon with Lemon Garlic Butter Sauce or Keto Tuna Patties. Eggs are another excellent source of healthy fats and protein and can easily be included in numerous recipes or enjoyed on their own. Additionally, coconut oil, MCT oil, butter, and ghee are all excellent fats for cooking, baking, and frying and can be added to bulletproof coffee for a quick boost of energy.
Meal Planning for Success
Someone starting a keto diet may struggle to eat the required amount of fat. Meal planning can help ensure a person gets enough fat each day. A person can include more fat in their diet by adding fats to hot drinks, using vegetables as a vehicle, making fat bombs, eating oily fish, choosing fatty cuts of meat, and eating fatty snacks.
What Happens If You Don’t Eat Enough Fat on Keto?
When fat intake is too low on a keto diet, several issues can arise, potentially undermining the health benefits of a low-carb diet and making it difficult to maintain. The most critical issue with not consuming enough fat on a keto diet is that it can make reaching or maintaining ketosis difficult. The fundamental principle of a ketogenic diet is to shift your body’s primary fuel source from carbohydrates to fat. If you’re not providing enough dietary fat, your body may struggle to produce enough ketones to fuel your cells. This can lead to fatigue, brain fog, and other symptoms commonly associated with the keto flu. Additionally, without sufficient fat intake, the body may start to break down muscle protein for fuel in the absence of carbohydrates. This may be especially problematic for individuals with a lean body composition as they have lower body fat stores to rely on. Additionally, fats are crucial for absorbing vitamins A, D, E, and K, and a lack of dietary fat can lead to deficiencies in these fat-soluble vitamins, negatively impacting overall health.
Who Shouldn’t Add Fat to Their Diet?
While fats are an essential part of a healthy diet, certain individuals may not benefit from adding more fat to their diet. It’s important to remember that while keto is a high-fat diet, the goal isn’t to consume excessive amounts of fat. Struggling to lose weight or uncomfortable digestive symptoms could be signs of eating too much fat. Hitting a weight loss plateau could indicate you’re taking in too much fat and your liver is turning dietary fats into ketones instead of burning your own body fat. You don’t want to go low-fat on keto, but you may want to try reducing your fat intake to around 75 grams per day. Additionally, if you introduce too much fat too quickly, the liver and gallbladder may struggle to process fats efficiently. People with type 1 diabetes should not try the keto diet due to the risk of ketoacidosis. Ketoacidosis occurs when excessive ketones produce a dangerous level of acid in the blood. People with healthy levels of insulin are unlikely to experience ketoacidosis.
Potential Benefits of Adding Healthy Fats to Your Diet
Incorporating healthy fats into your diet, especially within a well-formulated ketogenic diet, can offer numerous health benefits. Here are four benefits of adding more healthy fats to your diet:
1. Sustained Energy
Fats offer a steady source of energy, unlike carbohydrates, that can lead to rapid blood sugar spikes and energy crashes. Once your body adapts to using fat as its primary fuel source, you’ll experience more consistent energy levels throughout the day, avoiding the mid-afternoon slump common with high-carb diets.
2. Weight Management
While it might seem counterintuitive, increasing fat intake can actually aid in weight loss and weight management. Fat is very satiating, keeping you fuller for longer and reducing snacking between meals. Moreover, pairing higher fat intake with low carbohydrate intake helps stabilize blood sugar levels. This balance minimizes cravings, especially for sweet foods, by preventing blood sugar fluctuations that trigger hunger and overeating. The metabolic shift to fat burning promotes weight loss and more effective weight management as the body becomes more efficient at utilizing stored body fat as a fuel source.
3. Supports Brain Health
Approximately 60 percent of the human brain is composed of fat, which is crucial for the brain’s structural integrity and overall function. A significant portion of this fat is in the form of cholesterol and myelin, both of which are essential for optimal brain health and cognitive processing. Myelin, a cholesterol-rich membrane, surrounds nerve fibers and facilitates efficient transmission of electrical signals. The brain contains about 20 percent of the body’s cholesterol. This lipid is crucial for myelin formation, insulating nerve fibers, and facilitating neural communication. Additionally, cholesterol is the precursor to essential hormones such as testosterone, estrogen, and cortisol. Cholesterol also helps synthesize vitamin D, which is linked to a reduced risk of neurodegenerative diseases. Research emphasizes cholesterol’s critical role in maintaining neuronal integrity throughout a person’s life, underscoring its crucial role in hormone synthesis, forming cellular membranes, and supporting cognitive functions such as learning and memory.
4. Heart Health
Monounsaturated and polyunsaturated fats, found in foods such as extra virgin olive oil, avocados, and fatty fish, benefit heart health. These fatty acids help increase high-density lipoprotein (HDL), also known as good cholesterol, while decreasing low-density lipoprotein (LDL), commonly called bad cholesterol, linked to heart disease. Omega-3 fatty acids, abundant in oily fish, are particularly beneficial for cardiovascular health. They have been found to lower triglyceride levels, promote healthy blood pressure, help prevent arterial plaque buildup, and reduce the risk of arrhythmias.
Potential Risks and Side Effects
While the keto diet has its benefits, staying on it in the long term may have some negative effects, including risks of the following: low protein in the blood, extra fat in the liver, kidney stones, and micronutrient deficiencies. A type of medication called sodium-glucose cotransporter 2 (SGLT2) inhibitors for type 2 diabetes can increase the risk for diabetic ketoacidosis, a dangerous condition that increases blood acidity. Anyone taking this medication should avoid the keto diet. More research is being done to determine the safety of the keto diet in the long term. Keep your doctor informed of your eating plan to guide your choices.
When someone first transitions to the keto diet, they may experience what some people call “keto flu.” A person may experience symptoms such as fatigue, nausea, and dizziness. These symptoms usually resolve in a few days or weeks. There is not much evidence on the long-term impact of the keto diet. However, someone following the keto diet for an extended period may experience vitamin and mineral deficiencies, kidney stones, fatty liver disease, or abnormally low levels of protein in the blood.