What is Keto, Ketosis, and a Ketogenic Diet?

The term “keto” has become a buzzword in the health and nutrition world lately. There are keto snacks out there, you may have seen keto-friendly meal preps popping up, and some people are trying out the keto diet. But what IS keto? Let’s dive into the basics—welcome to Keto 101! A keto diet for beginners.

“Keto” is shorthand for ketogenic, which describes a particular kind of diet and lifestyle. Many people know it as a high fat diet, which may sound a bit strange… It sure sounded strange to me when I first heard of it!

We generally associate the word “fat” with fat on our bodies, but fat is also fuel. Dietary fats from whole foods provide our bodies with energy—but those fats that we eat actually aren’t the main cause for gaining more “fat” on our bodies. There are many factors at play with weight gain and weight loss. It’s more complicated than “calories in, calories out,” and the idea that “fat makes you fat,” is wholly inaccurate.

The ketogenic diet challenges these old beliefs, and it can get pretty confusing. That’s why I’ve compiled all of my learning and research into a Keto 101 video, to help break down the basics of the keto diet! There’s a lot to learn and it’s only an introductory video, but, if you’re curious about how a ketogenic diet works and the science behind it, it’s a good place to start.

Even if you’re not interested in trying out the keto lifestyle for yourself, understanding ketosis is a great way to learn more about how our bodies function. I’ve summarized the main points here, but check out the video for more detailed information and useful resources about keto, ketosis, and the ketogenic diet!

Keto 101 – Low Carb, Ketogenic Diet & Ketosis for Beginners


The information in my Keto 101 video and this blog post are intended for educational purposes only, and are not intended to substitute for advice from your doctor or healthcare provider. Also, I am not advocating for or against keto diets, and I am not claiming that a keto diet is either “right” or “wrong.” Only YOU can decide what’s right for you.

This information also is not a “how-to guide,” explaining how to start a keto diet. If you’re interested in a keto lifestyle for yourself, I highly recommend doing some serious research about it on your own before making any dietary changes! It’s important that you are aware of not only the benefits, but also the risks that may be associated with this type of diet change.

What is Keto?

  • Keto refers to the ketogenic diet.
  • A ketogenic diet is very low in carbohydrates, moderate in protein, and high in dietary fat.
  • The ketogenic diet was designed in the 1920s for patients with epilepsy, as a treatment option to help reduce their seizures.
  • Many of those patients on a keto diet also experienced other health benefits, like lowered body fat, stabilized blood sugar, lower cholesterol, and reduced hunger.


Calories on Keto

  • Calories provide fuel for our bodies.
  • Macros, or macronutrients, are what provide our bodies with those calories, in the form of carbohydrates, proteins, and fats.
  • Your daily carbs + protein + fat = 100% of your calories. The ratio of macronutrients that add up to that 100% will vary from person to person, based on what they eat.
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Keto Macros

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  • On a high carb low fat diet (HCLF), many people follow an 80/10/10 ratio: 80% carbs, 10% fat, 10% protein.
  • A competitive bodybuilding diet is typically higher in carbs, lower in fat, and moderate in protein to build muscle, but becomes much more high protein closer to their competition when they need to lean out.
  • A ketogenic diet is around 70% fat or more, moderate in protein, and only about 5-10% carbs. This keto ratio isn’t set in stone—it will vary based on the individual’s body, their carbohydrate tolerance, and their insulin resistance. One person may be able to eat more carbs than another person, but still be in nutritional ketosis.

This may be surprising if, like me, you’ve been taught to avoid fat and limit how much of it you eat. But, a keto diet functions differently than most traditional diets, which are higher in carbs. No macro ratio is objectively “right” or “wrong” for everyone. A specific macro ratio or lifestyle may work best for YOU, but it’s up to you to find that out! As you consider different lifestyles or macro ratios, it’s also important to know that different macronutrients contain different amounts of calories per gram. Specifically, fat has over twice as many calories per gram compared to carbs or protein:

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That means, on a ketogenic diet that’s high in fat, less food will quickly rack up more calories. In other words, you can meet your daily calorie needs eating a smaller volume of food. (But, because fat is more filling and satiating, a ketogenic diet can also reduce appetite and cravings!) It’s just something to be mindful of as you make decisions about how to best fuel your body.

Fat as a Fuel Source

Every person needs both carbohydrates AND fat in their diet for the body to function properly. Whether a person follows a high carb low fat diet or a ketogenic diet, they need at least some fat and some carbs. What makes a difference is the ratio—the amount of carbs relative to the amount of fat in a diet will determine a person’s fuel source. There are 2 main sources of fuel for our bodies: glucose or ketones.

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  • Fuel source that most people function off of today, also known as “blood sugar.”
  • Comes primarily from carbohydrates. Great source of energy for the brain and body.
  • When the body uses glucose as fuel, it is in glycolysis.
  • Since glucose is a sugar, this state is considered a “sugar burning mode.”

Ketone Bodies:

  • Fuel source on a ketogenic diet, instead of glucose.
  • Produced when glucose levels are lower and the body has access to fat.
  • When it’s using ketones as fuel, the body is in nutritional ketosis.
  • Fat is the fuel source, so this state is considered a “fat burning mode.”

When carbs are prevalent in a diet, the body is full of glucose and blood sugar levels rise. Because glucose is so easy to burn up, the body is inclined to use it as its first choice of fuel source. Think of it like this: glucose is a sugar, your body loves to gobble up sugar, and your body will gobble up glucose whenever it can get it.

But, when glucose levels drop low enough, the body turns to whatever fat is available—either stored body fat or dietary fat. This is when the body transitions to a new fuel source entirely: ketone bodies. Rather than burning up glucose for energy, a body in nutritional ketosis produces ketone bodies and uses them as fuel. This explains why carb intake has to be low and fat intake has to be high on a keto diet: in order to produce ketones, the body needs dietary fat to be prevalent enough and glucose levels to be low enough.

This also explains some of the initial side effects “keto flu” you may have heard about, which is the period during which our bodies transition from burning glucose to utilizing ketones.

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Ketogenic Diets Aren’t New

Though a large majority of people today are fueled by glucose, it isn’t our only viable energy source. Glucose is one source of fuel, ketones are another. Neither is “right” or “wrong,” they’re just different. One or the other may work better for you, but only you can find that out! The important thing is to know that both fuel sources exist. While the science and research behind ketosis is still new, the ketogenic lifestyle isn’t just a new trend:

Our ancestors may have lived keto lifestyles (without knowing it).

  • hunters and gatherers
  • “primal eating”—lots of nuts, seeds, meats, lower carb fruits like berries
  • diet that was high in fats and low in carbohydrates
  • likely resulted in ketosis: bodies could store that fat as energy, able to survive from one meal to the next

Traditional Inuit diets were likely ketogenic.

  • in the Canadian and Alaskan Arctic regions
  • hunting and fishing society
  • ate lots of whale/walrus blubber and fish—a diet high in fat and essentially free of identifiable carbohydrate
  • ketosis allowed bodies to survive long treks and hunting expeditions

Is a Paleo Diet a Keto Diet?

A paleo diet can be ketogenic, but not always.

  • can eat: grass-fed meats, seafood, fruits, vegetables, eggs, nuts, seeds, oils
  • can’t eat: grains, legumes, refined sugar, processed foods, dairy (typically), excessive salt
  • could result in a diet high enough in fat and low enough in carbs to produce nutritional ketosis
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A paleo diet is richer in dietary fats and lower in carbs, like a keto diet, BUT a paleo diet is not necessarily a keto diet. The two are distinctly different:


  • nothing is strictly prohibited
  • aims for an ideal RATIO of fats to carbohydrates
  • must be low enough in carbs, high enough in fats
  • can eat grains, legumes, sugars, etc., but likely wouldn’t do so regularly in order to stay in ketosis


  • certain foods and categories of foods are prohibited
  • limits the TYPES of foods one can eat
  • no limit to healthy carbs, no minimum amount of fats
  • can’t eat grains, legumes, sugars, etc.

Is the Atkins Diet a Keto Diet?

The Atkins Diet is similar to a ketogenic diet:

  • low carb diet: limits sugar, grains, starches, legumes, high carb vegetables and fruits
  • higher in fats: meats, seafood, eggs, full-fat dairy, oils, nuts and seeds

but it’s not the same. There’s one major difference between Atkins and keto:

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  • for nutritional ketosis to occur in the body, a diet must be moderate in protein


  • allowed to eat as much fat and protein as you want, with no limit to protein intake

The body can only process so much protein, until it must convert the excess protein into usable energy: glucose. This is a process called gluconeogenesis. If a keto diet is too high in protein—even if that diet is high enough in fat and low enough in carbs—it can send the body back into sugar burning mode, a.k.a. glycolysis. The amount of protein and carbs that a person can eat on a keto diet will vary, depending on how their individual body metabolizes different foods.

BOTTOM LINE: low carb does not necessarily equal ketosis. Diets like paleo and Atkins can be perfectly healthy and help many people live healthier lives, just don’t confuse them with a keto diet. Rather than seeking to eat or limit certain types of foods, the ketogenic diet is about using fat as fuel. Nutritional ketosis is a biological process in the body that requires the right ratio—high enough fat, low enough carb, and not too much protein—for that specific individual’s body and metabolism.

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Through emerging research and the personal accounts of those living a low carb lifestyle and eating low carb foods, we’re starting to understand some of the many benefits of a keto diet:

  • Weight loss: the body burns stored fat to help you lose weight
  • Reduced appetite: dietary fat is more satiating so people often don’t feel as hungry; can also improve a person’s relationship with food
  • “Mental clarity”: people often report experiencing a level of “mental clarity” in ketosis that they don’t have when fueled by glucose
  • Healing: studies have shown ketosis can help kill cancer cells; can help treat or even reverse cognitive impairments like Alzheimer’s symptoms
  • Stabilize blood sugar: less glucose in the body results in fewer/no blood sugar spikes
  • Lower insulin: blood sugar spikes cause insulin spikes, which makes us feel hungry even after just eating, but less glucose in the body = fewer/no blood sugar spikes = fewer/no insulin spikes
  • Reduce blood pressure
  • Improve blood cholesterol & triglyceride levels

What to Eat on a Keto Diet

We know a ketogenic diet is high in fat and low in carbs, but most people following a keto lifestyle also consider themselves on a whole foods diet. This means eating real, wholesome foods, while staying away from packaged and processed foods. But, while nothing is totally off limits on a keto diet, there are still some whole foods that would likely be avoided because they’re higher in carbs.

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General Keto Foods:

  • leafy and cruciferous veggies
  • grass-fed meat
  • eggs
  • wild-caught fish
  • dairy (depending on the person)
  • olive oil, coconut oil, grass-fed butter, ghee
  • avocado
  • nuts and seeds

Foods to Avoid on Keto:

  • processed foods
  • foods high in sugar
  • grains and breads
  • quinoa
  • starches, like sweet potatoes or corn
  • higher sugar fruits, like bananas and pineapple
  • legumes

Plenty of these foods—like sweet potatoes, bananas, beans—are perfectly healthy and nutritious foods, they’re just difficult to fit into a keto lifestyle specifically. Too many carbs and sugar means glucose is available to the body, so it won’t produce ketones! There’s really no “good” or “bad” when it comes to whole foods. It’s all relative. What’s good for one body can be different for another, especially when we’re running on different fuel sources!

Is Fat Bad?

Educating ourselves about health and nutrition is so crucial, especially because the science behind it is always changing. Many of the things we’ve been taught to avoid, like butter and beef, actually can be a part of a healthy lifestyle—IF they’re grass-fed and not processed, while also not being combined with a high carbohydrate intake. Saturated fats have long been demonized as “unhealthy fats” that lead to heart disease, while unsaturated fats like omega-3-6-9s have been deemed “healthy fats.” But, new dietary research is now challenging our old beliefs about different forms of dietary fat:

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Saturated fats:.

  • natural fats found in meats, butter, full-fat dairy, coconut oil, fish, eggs, nuts, seeds, avocados
  • dated research linked saturated fat intake to high cholesterol and heart disease; the American Heart Association (AHA) still today recommends limiting saturated fats
  • new research has found that dietary saturated fat isn’t associated with an increased risk of heart disease and doesn’t have the harmful effect we once thought
  • saturated fats from whole foods are highly nutritious; grass-fed meat and dairy are richer in vitamins and nutrients than grain-fed
  • there’s a stronger link between chronic inflammation and heart disease, as well as trans fats and heart disease
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Trans fats:

  • unnatural, man-made fats; made by partially hydrogenating fats and oils
  • found in many processed foods and baked goods
  • there’s a significant link between trans fats and heart disease—an analysis of existing studies found that people who ate more trans fats were 21% more likely to develop heart disease and 28% more likely to die from heart disease
  • the one type of fat that everyone agrees (even the FDA) is bad and unsafe to consume
  • just a reminder: always avoid!

Scientists and doctors are still trying to better understand just how the body works, how we metabolize foods, and what plays a role in chronic diseases. Saturated fat actually isn’t the demon of heart disease we believed it to be decades ago, and it can be a part of a healthy diet. But, as we accept that fats are fuel, we still have to consider the balance of fats, carbs, and protein, within the 100% of our daily macronutrient pie. You have to explore and decide what kind of ratio suits you!

Who Might Consider a Keto Diet?

For some people, a ketogenic diet can have serious health benefits and move them closer to their health goals. And, many people even find that a keto diet helps them to overcome a weight loss plateau! But, like any diet, keto isn’t for everyone.

A keto diet might help those who:

  • have a goal of weight loss
  • have struggled with insulin sensitivity and/or being overweight
  • are trying to reset their appetite center and be more mindful of being full
  • have a goal of reducing blood pressure and finding healthy cholesterol levels
  • are looking for help with PCOS treatment
  • have neurodegenerative disorders

But, of course, a ketogenic diet is not appropriate for everyone, like those who:

  • have kidney or liver disease
  • live with Muscular Dystrophy
  • have gallbladder disease
  • underwent gastric bypass surgery
  • have rare metabolic disorders
  • have pancreatic insufficiency
  • are prone to kidney stones
  • live with Type 1 diabetes (for people with type 2 diabetes it depends, so it’s best to get a doctor to supervise)
  • have blood sugar issues like hypoglycemia
  • are pregnant, nursing, or have gestational diabetes

Keto may also not be a good idea for:

  • people who have suffered from an eating disorder
  • people who have a history of mental health problems
  • children or people under the age of 18
  • people who are naturally very thin with a BMI of less than 20
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Is a Keto Diet for Me?

Before committing to a keto diet, you have to be well-informed. If this introductory information has piqued your interest, delve deeper and learn more! Check out the Keto 101 video and, as always, I encourage you to keep doing your own research. There’s so much out there!

Of course, it’s a good idea to get a general health screening before making drastic dietary changes. Talk to your doctor and make sure there’s no rare conditions or contradictions with your health or medications that might be affected by a ketogenic diet. But, because the science surrounding ketosis is still emerging, be prepared—your doctor may discourage you from a keto lifestyle.

Ketogenic diets are often placed in the same class as “alternative medicine,” with practices like acupuncture and even chiropractics. Like many forms of alternative medicine, ketogenic diets are just beginning to be understood. More researchers are starting to study ketosis, but the diet hasn’t been widely accepted into standard medical practice yet. Still, this doesn’t change the fact that the keto lifestyle has helped and is helping many people along their health journeys today.

It’s not for everyone, but ultimately YOU have to decide! Consult your doctor’s opinion, do your own research, and listen to your body. Learn what works for you. Inform yourself so you can make better decisions about your health and lifestyle. And, no matter what, you do YOU. You know your body best!