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Vitamins & Supplements
What is a Keto Diet?
Lindsey Toth, MS, RD • July 23, 2020

Trendsetting-celebrity endorsements have the internet buzzing about the keto diet. It’s topping newsfeeds and sneaking into inboxes everywhere. But what is the keto diet craze all about? Should you try the keto diet? And how does it even work?

This diet definitely isn’t right for everyone. The keto diet is an extremely low-carb, high-fat diet that essentially tricks your body into thinking it’s fasting. The goal of this method is the same as many other weight-loss diets—to get your body burning stored fat.

Ketogenic diets involve a complete overhaul of what you eat, and not always for the better. Before starting a keto diet, you should talk with your dietitian or doctor about which diets are right for you and your lifestyle; but we want to shed some light on how this diet works and what it entails, to help you better understand the ketogenic diet trend that’s sweeping the web.

Keto Diet History

The keto diet dates back to the 1920s when researchers were looking for a therapeutic alternative for patients who needed some of the effects of fasting to help with a particular set of health concerns.1 But since fasting can be difficult, if not impossible, to maintain for long periods of time, the researchers developed a method to mimic a fasting metabolic state.

For those initial researchers, weight loss on the keto diet was more of a side effect than a primary goal. And the use of the keto diet stayed primarily in the medical world with high rates of success until it gained some celebrity press in the 90s.

Since then, several ketogenic-related diets have surfaced that you’ve probably heard about, including the MCT diet and the Atkins diet. But the keto diet has remained in the spotlight, and even more so now that certain celebrities have given it a try.

How Does the Keto Diet Work and What is Ketosis?

To understand how the keto diet works, you’ll need to understand ketosis. Ketosis is a physiological state that happens when carbohydrate intakes are significantly reduced.2 When your body is in ketosis, it burns fat for fuel, both from the foods you eat and from your body’s fat stores. You go into ketosis naturally when you fast or after physical activity has depleted your glycogen stores.3

But wait, what’s glycogen? Glycogen comes from carbs. When you eat carbs, like grains and sugars, they are broken down into glucose, which your body turns into glycogen to use as a quick source of energy.3 By limiting carbohydrates to a very low level, your body doesn’t have access to glycogen. When that happens, your liver starts producing something known as ketones for your body to use for energy instead. Ketones are water-soluble molecules that the liver produces by breaking down fatty acids. Your body makes and uses ketones for fuel when glycogen isn’t available.

When overall food intake is low, like during a fast, this natural process causes your body to use up fat stores. That’s what allows humans to survive without food for a little while. During a fasted state, your body releases stored fat from fat cells which your liver then turns into ketones to fuel your body. And since a reduction in glycogen is more or less the trigger for this process, you can trick your body into ketosis by making some changes to your diet.

Stages of Ketosis

The goal of a keto diet is to get you into that ketogenic state and keep you there as much as possible, but it doesn’t happen instantly. It takes a little time for your body to adjust and switch over to making ketones. How long that takes depends on your body, activity levels and what you’re eating. Sometimes it takes a few days or up to a week. Everyone is different.

How do you know when you’re in a ketogenic state? You can pick up some keto test strips from most pharmacies. They measure ketones in urine. There are more in-depth tests out there, including breath tests and blood ketone meters if you want to dig deeper, but keto test strips will get you started.

Potential Benefits of Ketogenic Diet

If you’re going on a keto diet, the benefit you’re probably looking for is fat loss. A lot of people have lost significant amounts of weight on a keto diet, including some celebrities.4 But that doesn’t mean it’s completely healthy. When you eliminate a category of foods from your diet you also eliminate nutrients. But here are some of the potential benefits dieters seek from a keto diet.

Less Hunger?
You may be less hungry on a keto diet than some other restrictive diets because fats and proteins can be really filling. You can also eat filling, fiber-rich greens.

Reduced Temptation to Cheat?

This is another potential benefit of a diet focused on foods that are filling—you may be less likely to cheat. And the keto diet isn’t as restrictive in total calorie intake as some other weight-loss diets.

Cognitive Performance?

Some researchers believe ketones are a preferred fuel source for the brain.5 Also, you will most likely eat a lot of brain-healthy omega-3 fatty acids on a keto diet. But you probably wouldn’t notice cognitive benefits right away. The first few days on a keto diet can be tough mentally since your body is accustomed to looking to carbs for energy.

Fewer Fat Stores?

You may not store as much fat from the foods you eat while on a keto diet. Since you won’t be eating as many carbs, your body won’t make as much insulin, which triggers your body to store fat.6

Detox Benefits?

There may also be some detox benefits while on a keto diet, depending on your food choices. If you go with organic and grass-fed foods, even better. But you don’t need to go on a keto diet to make the switch to real foods. Read Real Food: A Revival or a Revolution? to find out why you should always keep it real.

Burn Fat for Energy

The keto diet may help get your body to use fat stores for energy, but so do many other diet and weight-loss plans.

Keto Diet Plan

The keto diet is based on specific intake percentages of fats, protein and carbs. Instead of limiting you to a strict menu or providing directions on exactly what to eat each day, the standard keto diet specifies the percentage of your daily calories you should get from each food type and offers some guidelines based on your ideal body weight.

Fat Intake on a Keto Diet
On a standard keto diet, the goal is to get about 75% of your daily calories from fat.7 It’s best to focus on healthy fats from sources like fatty fish, coconut oil, grass-fed butter, avocados and olive oil. Read Be Fat Fluent: Best Fatty Foods for Your Diet for more ideas.

Protein Intake on a Keto Diet
Protein makes up around 20% of your daily calories on a standard keto diet.7 For females that should include around 1.2 gram of protein for every kilogram of ideal body weight.8 And for males, make that 1.4 grams of protein for every kilogram of ideal body weight.8 So, if you’re female and your healthy, ideal weight is 145 pounds (65.8 kilograms), you would aim to eat around 79 grams of protein every day. Check with your doctor or dietitian if you don’t know your ideal weight, so you don’t underestimate or overestimate.

Carbohydrate Intake on the Keto Diet

The standard keto diet specifies that carbs should be limited to around 5% of your daily calorie intake.7 That means keeping a very close eye on carbohydrates. This is where the keto diet can get really tricky because you may end up depriving yourself of some valuable nutrients when you swap most of your carbs for high-fat foods. A lot of healthy foods contain some carbohydrates, including many vegetables and whole grains.

Keto Diet Water Intake

Hydration is always important; but on a keto diet water helps flush out toxins, helps keep you from feeling hungry and aids digestion. Men should aim for 15.5 cups (3.7 liters/124 ounces) and women 11.5 cups (2.7 liters/92 ounces) of fluids a day every day—not just while you are dieting.9

There are alternative versions of the keto diet out there, including an option that is higher in protein and follows a ratio of 60% fat, 35% protein and 5% carbs.7 But the information above is based on the standard keto diet.

Keto Diet Foods

So, what do you eat on a keto diet? Before starting a keto diet, you will want to brush up your knowledge on healthy fats since fat is the cornerstone of the keto diet. But the key word there is healthy. Not all fats are good for you, but some of them are. You should also eat plenty of nonstarchy, low-carb veggies and get enough dietary fiber to help keep your digestion running smoothly. This is not an exhaustive list, but here are some examples of keto-friendly foods below.

Keto Foods


  • Leafy greens like arugula, spinach, kale
  • Celery
  • Cucumber
  • Cabbage
  • Green beans
  • Broccoli
  • Black olives
  • Leeks
  • Tomatoes
  • Zucchini

Meat, Fish, Poultry

  • Red meat
  • Chicken
  • Pork
  • Veal
  • Lamb
  • Liver and organ meats
  • Fowl
  • Shrimp
  • Crawfish
  • Crab
  • Lobster
  • Scallops
  • Salmon

Fats and Dressings

  • Grass-fed butter
  • Olive oil
  • Avocado oil
  • Coconut oil
  • Low carb dressings


  • Herbs and spices
  • Balsamic vinegar
  • Red wine vinegar
  • Mustard
  • Hot sauces (check the label for carbs)
  • Pickles
  • Monk fruit sweetener as a natural, low-carb option


  • Gruyere
  • Neufchatel
  • Cheddar
  • Fontina
  • Havarti
  • Swiss
  • Parmesan
  • Gouda
  • Mozzarella

Dairy and Alternatives

  • Half-and-half
  • Heavy cream
  • Eggs
  • Unsweetened almond milk


  • Water
  • Sparkling water
  • Unsweetened tea
  • Herbal tea
  • Keto coffee

The Keto Diet Avoids These Foods

  • Grains
  • Sugars
  • Artificial sweeteners
  • Processed foods
  • High-carb root vegetables

Again, this is not a complete list. While you’re on a keto diet, food choices are yours to make as long as you monitor carbs and your ratio of fats to protein and carbs.

Keto Diet Menu

The keto diet allows a lot of menu flexibility despite its limitations. As long as you stay within the ratio guidelines, your menu is up to you and you can switch things up every day. That makes this diet an attractive option for people who have trouble sticking to predefined diet menus. It also makes things a little less complicated. Who hasn’t encountered items on a diet menu that are hard to find or don’t provide options for dining out? No matter where you are, you should be able to find suitable keto foods.

But again, the same goes for many other diets, including just deciding to make better food choices in general by focusing on nutritious, whole-food options.

Keto Meal Plan

Just because the keto diet doesn’t demand that you stick to a specific meal plan doesn’t mean you shouldn’t plan at all. Stock your pantry with real food and healthy, keto-friendly staples and make sure you have all the ingredients on hand to whip up delicious, nutritious meals every day.

Also, you will want to track your meals closely to keep an eye on fat, protein, carbs and your overall nutrition. You can do that by looking up nutritional info in the United States Department of Agriculture (USDA) Food Composition Database and writing it all down in a journal each day, or signing up for a free online or app-based nutrition tracker.

Here are some examples of keto-friendly meals:

Breakfast Ideas

  • Egg omelets with veggies and meats
  • Keto coffee (learn how to make it in the post What is Keto Coffee?)
  • Baked eggs in avocado halves

Lunch Ideas

  • Lettuce wraps with your favorite low-carb fillers (chicken, tuna salad, etc.)
  • Salads, full of low-carb veggies and healthy-fat dressing
  • Low-carb, broth-based soups

Dinner Ideas

  • Baked salmon and asparagus
  • Surf-and-turf style grilled kebabs
  • Bunless burgers

Sounds delicious, right? Not bad for a diet. There are some vegan and vegetarian keto options too, including low-carb and high-protein meat alternatives, mushrooms, leafy greens, and fermented foods like sauerkraut and kimchi.

Supplements for Keto Diets

If you plan to go keto, supplements may help keep your nutrients and energy levels up. The keto diet eliminates a lot from your diet, so you will need to fill in those nutritional gaps. The supplements below are ideal while on a ketogenic diet because they help provide your body with much-needed support during and after the transition to burning ketones, and to help keep you healthy for the duration of your ketogenic journey and beyond.

Potassium Supplements–Potassium is a type of electrolyte that supports nerve function and muscle contraction, as well as heart health; and it helps move nutrients into cells and waste products out of cells.10 Try Swanson Premium Potassium Gluconate.

Electrolyte Supplements–Reducing carbs and eating more whole foods may also mean that you are reducing the amount of sodium in your system, which can affect fluid levels. Supplement your diet with an electrolyte supplement, like Triple Pyruvate Electrolyte Complex.

Magnesium Supplements–Magnesium helps regulate protein synthesis, muscle and nerve function, blood pressure regulation and blood glucose control, and it’s essential for energy production.11 Opt for a highly bioavailable form of magnesium, like our Triple Magnesium Complex.

Fish Oil or Krill Oil SupplementsKrill oil and fish oil supplements are both excellent sources of omega-3 essential fatty acids (EPA and DHA), and krill oil contains astaxanthin, a powerful antioxidant.12 Get an extra dose of astaxanthin in Swanson EFAs Krill Oil & Astaxanthin.

MCT Oil or Coconut Oil–More than 50% of the fats in coconut oil are MCTs, which are converted to ketone bodies.13 Studies also show that MCT oil may enhance weight loss and help you lose fat.14 Find it in our Certified 100% Organic Extra Virgin Coconut Oil or 100% Pure MCT Oil.

Amino Acid Supplements–Amino acids play important roles in building and maintaining muscle tissue.15 Help protect your muscles during diet and weight loss efforts by boosting your intake with amino acid supplements like L-arginine and L-Ornithine.

Digestive Enzymes–Take a daily digestive enzyme to help your body more easily break down fat and proteins. The enzyme lipase may be especially helpful while adjusting to a high-fat, high-protein diet.16 You’ll find it in Swanson Ultra BioCore Optimum Complete Ultimate Full Spectrum Enzymes.

Vitamin D Supplements–While most keto diets do allow dairy products, including milk fortified with vitamin D, dairy milk can be high in carbs so many people avoid consuming too much of it while on a keto diet. Keep your vitamin D levels up by supplementing your intake. Try a high-potency vitamin D-3 supplement.

Probiotic Supplements–Keep your gut and immune system happy by making a probiotic supplement a regular part of your keto-diet routine. Swanson Health’s Probiotic for Digestive Health is a great option. Learn more about the benefits of probiotics in Trust Your Gut Health: Build a Healthier Gut with Probiotics.

Multivitamin without Iron–Multivitamins are great for filling in nutritional gaps, and while you are on a ketogenic diet you will most likely already consume a lot of iron, so opt for a multivitamin without iron, like Swanson Health’s Premium High Potency Multi Without Iron.

Eating Keto

The ketogenic diet might seem easier to follow than some other diets, but that doesn’t mean it’s a walk in the park, especially not at first. And it may not be the best diet for your nutritional needs or lifestyle, so don’t forget to check with your doctor or dietitian first.

If you do start a keto diet, plan the timing so you will have plenty of time to rest and take care of yourself. Stay hydrated, be kind to your body while it adjusts to the changes in your diet, and support your nutritional needs with supplements.

For tips on taking care of yourself, read Take Care of U: 6 Ways to Take Care of Yourself, and Say Om: 6 Tips to Help You Relax and Reduce Stress.

Have you tried a keto diet? How did you feel about it? Which supplements did you take to cover your nutritional gaps? Tell us all about it in the comments below!

Lindsey Bristol, Swanson Health Products



About Lindsey Toth, MS, RD
Registered Dietitian, Swanson Health

Lindsey is a nationally recognized registered dietitian and nutritionist with a soft spot for ice cream. She empowers people to take charge of their health by finding the balance between the pleasure and nourishment in food. 

Her philosophy is that you should take care of your body because it’s the only permanent home you have. It’s what inspired her to pursue a career in nutrition and, ultimately, led her to Swanson Health.


1 History of the ketogenic diet. PubMed. https://www.ncbi.nlm.nih.gov/pubmed/19049574 (Accessed 03/16/2018)

2 Ketosis: What is ketosis? Medical News Today. https://www.medicalnewstoday.com/articles/180858.php (Accessed 03/16/2018)

3 7 Tips to Get Into Ketosis. Healthline. https://www.healthline.com/nutrition/7-tips-to-get-into-ketosis (Accessed 03/16/2018)

4 The keto diet, explained. Vox. https://www.vox.com/science-and-health/2018/2/21/16965122/keto-diet-reset (Accessed 03/16/2018)

5 Ketones: Your Brain’s Preferred Fuel Source. Dr. Maleah Holland. Ketogenic.com https://ketogenic.com/therapeutics/ketones-your-brains-preferred-fuel-source/ (Accessed 03/16/2018)

6 Insulin effects in muscle and adipose tissue. PubMed. https://www.ncbi.nlm.nih.gov/pubmed/21864752 (Accessed 03/19/2018)

7 The Ketogenic Diet 101: A Detailed Beginner's Guide. Healthline. https://www.healthline.com/nutrition/ketogenic-diet-101 (Accessed 03/16/2018)

8 How much protein is enough? The Ketogenic Diet for Health http://www.ketotic.org/2014/01/how-much-protein-is-enough.html (Accessed 03/17/2018)

9 Water: How much should you drink every day? MayoClinic. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/water/art-20044256 (1/18/2018)

10 National Institutes of Health: U.S. National Library of Medicine. Potassium. https://medlineplus.gov/potassium.html (Accessed 10/31/2017)

11 Magnesium Fact Sheet for Health Professionals: National Institutes of Health. https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/ (Accessed 11/30/2017)

12 Free Radical Scavenging and Cellular Antioxidant Properties of Astaxanthin. US National Library of Medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4730345/ (Accessed 03/17/2018)

13 Coconut oil and palm oil's role in nutrition, health and national development: A review. US National Library of Medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5044790/ (Accessed 3/08/2018)

14 Weight-loss diet that includes consumption of medium-chain triacylglycerol oil leads to a greater rate of weight and fat mass loss than does olive oil. US National Library of Medicine. https://www.ncbi.nlm.nih.gov/pubmed/18326600 (Accessed 3/08/2018)

15 Effect of Amino Acid Supplementation on Muscle Mass, Strength and Physical Function in Elderly. US National Library of Medicine https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2430042/ (Accessed 03/17/2018)

*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease.