What is the Keto Diet? A Comprehensive Guide for Beginners


Search for solutions to your ongoing battle with maintaining a healthy weight, and it won’t be long before the keto diet enters the conversation. 

Praised as an effective, low-carbohydrate diet, keto (or ketogenic, to use its full name) has blossomed into a multi-billion dollar industry, with reports that some 39% of Americans have used it to achieve their ideal weight.

But precisely what is the keto diet? 

How does it work, and is it even safe?

If these are the questions you’ve been pondering to achieve your health goals, this guide has the answers you’re looking for and more.

Below, we’ll outline everything you need to know about the pros and cons of the keto diet to help you determine if it’s the right weight-loss strategy for you. 

What is the Keto Diet? A Brief Overview

keto diet

The keto diet is a means of losing weight by replacing most carbohydrates with fats, forcing the body to rely on them as its primary fuel source.

Generally, when we follow a typical Western diet, our bodies create the energy we use in our day-to-day lives by burning carbohydrates and sugars. However, this is a slow and relatively inefficient way to burn energy, which is why eating a diet high in carbs can lead to weight gain or, at the very least, make it difficult to lose weight.

Still, carbohydrates do have some uses. 

Nutrient-rich carbohydrates, such as whole grains, starchy vegetables, and some fruits, promote healthy digestion and aid cognitive function, so it’s wise not to rule them out altogether. 

The keto diet ultimately reduces our carb intake to the bare minimum required to stay healthy while consuming the rest of our dietary intake through fats. 

When we do this, the body enters a state known as ketosis in which it burns up that fat to produce chemicals in the liver called ketones. 

These ketones then become our primary energy source.

For people trying to reach their ideal weight, voluntarily placing their bodies in a state of ketosis can be an effective way to achieve this goal for two main reasons: 

  1. Burning fat is a much more efficient way to generate energy than carbohydrates. You’ll burn more energy faster, which can be incredibly effective at shedding the visceral fat around your belly.
  2. Ketosis helps you to feel full much quicker than if you were eating a regular carb-heavy diet, so you feel less hungry throughout the day and, thus, are inclined to eat less. 

Still, dropping the pounds isn’t the only reason people switch to a ketogenic diet. 

Since fats typically come from food sources that also contain good protein levels, it can be an effective way to enjoy the benefits of increased protein intake, such as developing muscle mass, strengthening your bones, and even lowering blood pressure

Where did the Keto Diet Come From?

Though the keto diet has exploded in popularity in the last few decades, even some of its most ardent champions may be surprised to note that its origins date back to ancient Greece.

Around 400 BC, a work called On the Sacred Disease was published. Found in the collection of texts we call the Hippocratic Corpus, the work touches on epilepsy and suggests that altering a person’s diet -primarily through fasting- could alleviate the condition. 

Though the Greeks believed that epilepsy had supernatural causes, the idea that diet could be used as an effective therapy stuck around as modern medicine developed; since then, we have begun to learn more about how the human mind and bodywork. 

20th Century Developments

By the early 1900s, medical experts such as Michigan-based physician Dr. Hugh Conklin began to explore how depriving the body of sugar through fasting could be used to flush the body of a toxin he believed to be the root cause of epileptic seizures. 

Conklin’s work produced results, with some 50% of his patients showing a marked improvement and 20% experiencing no more seizures after trying his fasting diet. 

By the turn of the 1920s, experts began looking for ways to produce the same results that could be sustained more long-term than fasting. 

If you’re interested, here is a list of keto foods for seizures.

The Rise, Fall, and Rise of the Ketogenic Diet

A 1921 study by Dr. Wyatt discovered that ketonemia (a high level of ketones in the blood) could be produced by minimizing carbohydrates and dramatically increasing fat intake. This approach ultimately proved to be every bit as effective as outright fasting. 

Thus, the original ketogenic diet was born.

As the 20th century wore on, advances in antiepileptic medication meant that the keto diet fell rapidly out of favor with modern physicians. It wasn’t until 1994 when the approach was featured on a television show in the United States, that interest in the diet began to reemerge.

Ketogenic research sharply declined in the mid-1900s, but the method became famous as a treatment for children. Studies showed that it could be as much as 90% effective in reducing the frequency of epileptic seizures in children

The diet was even more effective than other antiepileptic medicines in children with refractory epilepsy, a form of illness that doesn’t respond well to traditional medicines. 

Seeing how effective it could be, it didn’t come as much surprise when medical researchers began looking into the positive effects of ketogenic diets on cognitive function and how this could be used as a possible therapeutic cure for a range of neurological illnesses such as Alzheimer’s Disease, autism, headaches, and even sleep disorders. 

How Keto Became a Tool for Weight Loss

lose weight on keto

So far, so fascinating, but how did this medical treatment become such a popular tool for adults struggling to achieve a healthy weight?

The answer lies with another popular low-carbohydrate diet, the Atkins Diet

Around the same time the ketogenic diet was enjoying its rise back to prominence, New York physician Robert Atkins’ famous namesake diet exploded in popularity.

It didn’t take long for people to begin noticing the similarities between the Atkins Diet and the Keto Diet, and, seeing it as a more effective -albeit also more extreme- low-carb diet, made the switch.

The rest, as they say, is history. 

Millions of people worldwide have since adopted a keto diet, with numerous research reports showing that those who do typically lose anywhere from 30 to 60+ pounds

What is the Correct Way to Do a Keto Diet?

At its core, keto is a pretty specific diet to follow:

Fewer carbs, more fat, and a moderate amount of protein. 

If you’re following the standard ketogenic diet, a general rule of thumb is to break down your food intake as follows:

  • 70% fat
  • 20% protein
  • 10% carbohydrates.

Most health experts recommend that adults consume around 2,000 calories daily to get enough nutrients and energy. 

To achieve this target, you should consume no more than 40 grams of carbohydrates, 75 grams of protein, and 165 grams of fat.

If that sounds like far too much math to wrap your head around, you can make life easier using a keto calculator to help you develop the ideal keto-optimized meals to achieve your goals based on your circumstances. 

Once you start following this plan, the time it takes to get into ketosis typically only takes a few days. However, in some circumstances, it can take as long as two weeks, depending on your health and personal affairs.

What are the Different Types of Keto Diet?

The guidelines listed above are for the keto diet’s standard version, the one most commonly adopted by those looking to lose weight.

However, this blueprint has been expanded or revised to help others achieve specific goals, creating several different keto diet variations. 

These include: 

1. Cyclical Ketogenic Diet (CKD)

As the name implies, a Cyclical Ketogenic Diet involves cycling between low and high-carb days.

For five or six days out of the week, you stick to the usual macros of the standard keto diet. These are your low-carb days.

On the remaining one or two high-carb days, days (which you shouldn’t do back-to-back), you switch things around with the following macros:

  • Fat – 10%
  • Protein – 20-30%
  • Carbohydrates – 60 – 70%. 

For a typical diet of 2,000 calories, this would mean eating up to 400 grams of carbs on these days.

One of the main reasons why people switch to CKD is for weight maintenance and general management. 

Some people find it easy to lose weight quickly on a keto diet but are dismayed when they return to eating a regular diet and pile those pounds back on. 

Taking this cyclical approach prevents that. It provides you with the benefits of ketosis while still offering the opportunity to enjoy some of the many foods that should be avoided on a keto diet

CDK is also sometimes used by serious athletes and those who engage in high-intensity activities such as High-Intensity Interval Training (HIIT) or bodybuilding. Such individuals can find that a standard keto diet negatively affects their performance. Hence, they switch to a CDK to boost the amount of glycogen in their bodies to up the energy they can expend at a big event or competition.

Whatever the reason, if you’re considering using a Cyclical Ketogenic Diet, it’s smart to do the regular diet for at least a month first. This way, your body gets used to ketosis, meaning you can return to that state much more efficiently after your high-carb days. 

2. Targeted Ketogenic Diet (TKD)

At first glance, a Targeted Ketogenic Diet (TKD) may seem very similar to a CKD, as the two are often used by those engaged in physical activity and exercise. 

TKD and CKD differ because the latter is mainly used for high-intensity, competitive-level activity. In contrast, the former is generally used for more moderate workouts, such as regular gym sessions. 

Often used by those who find their strength and conditioning aren’t up to their usual standards once in ketosis, this approach involves following the standard keto diet 99% of the time and eating between 15 and 50 grams of carbs 30-60 minutes before a workout. 

To get the best results, TKD followers are advised to stick to carbs that absorb quickly in the body and are high in glucose and dextrose, such as hard candies, Gatorade, gummy bears, or healthier alternatives like white rice and potatoes

3. High Protein Ketogenic Diet (HPKD)

The main reason protein intake is so limited in the standard ketogenic diet is that having too much protein in your system can reduce the level of ketones in your body. Thus, making it much harder to achieve the same state of ketosis you’re trying to create with this diet. 

With a High Protein Ketogenic Diet (HPKD), you increase your protein intake by a small amount, just enough to reap the benefits while reducing -though not eliminating- its negative effect on ketone production. 

Doing so helps keep the muscles healthy and strong, which is why it’s equally popular with bodybuilders as it is with older people at a higher risk of muscle deterioration. 

This diet uses the following macros:

  • 65% – Fat
  • 30% – Protein
  • 5% – carbohydrates.

If you recall, the standard ketogenic diet calls for 20% protein, which provides the extra protein you need to protect your muscles without entirely booting you out of ketosis. 

What Foods Can You Eat on a Keto Diet?

keto food

For some people, switching to a keto diet can mean a radical overhaul of their diet as it not only eliminates sugar and foods we know they are unhealthy for us, such as chips and bread, but also severely restricts our intake of other high-carb foods like grains, potatoes, and fruits that are high in sugar. 

The good news is that as you develop your favorite keto meal plans, you’ll discover many delicious foods you can still enjoy. These include: 


There’s a good reason why fish and other seafood feature so prominently in keto recipes:

Not only do they not have any carbs, but they’re also rich in protein and potassium. Add fatty fish like salmon, tuna, or mackerel to the occasional meal, and you’ll also benefit from extra omega-3 fats that are useful for maintaining healthy blood sugar levels. 


While high-carb vegetables like potatoes should be kept to a minimum, plenty of other veggies are low in carbohydrates and incredibly good for you. 

Green vegetables like cabbage, spinach, and avocados provide valuable antioxidants, can help promote a healthy gut and even reduce your risk of heart disease. 

Tomatoes, bell peppers, green beans, and asparagus are tremendous keto-friendly vegetables to add to your diet. 


Cheese features in many of the tastiest keto recipes, like this cauliflower and pistachio cheesy bake and the irresistible keto cheeseburger casserole

That’s not just because cheese is delicious. It’s because it also has no carbs and plenty of fat.

Other dairy-based products like eggs and even plain Greek yogurt can help you achieve your weight loss goals faster as they make you feel full sooner than other foods and stay full for longer. 

Fresh Meat and Poultry

Fresh meats and poultry like beef and pork, chicken, and -to a lesser extent- turkey are all great zero-carb additions to your diet. They contain a decent amount of healthy fats while providing protein, potassium, and zinc.

While we love a good bacon sandwich as much as the next person, processed meats have been linked to an increased risk of heart disease and some forms of cancer, which means it’s best to limit your intake to those rare treats and stick with the fresh stuff. 

Nuts and Seeds

Almonds, brazil nuts, pecans, and macadamia nuts contain very few carbohydrates yet are an excellent source of polyunsaturated and monounsaturated fats, precisely the kind of healthy fats you want in your keto diet. 

Here is a list of the best nuts for keto.

Seeds such as pumpkin, chia, and flaxseeds are great low-carb snacks offering plenty of additional health benefits. 

Olive Oil and Coconut Oil 

When cooking and preparing your dishes, the healthiest option is olive oil, which can reduce the risk of heart disease.

Coconut oil is also a keto staple as it can boost the production of ketones, though it does have a higher concentration of saturated fats.

Tea and Coffee

If you can’t get your day started until you’ve had your morning caffeine fix, you’ll be relieved to know that coffee and tea are both perfectly acceptable on a ketogenic diet.

However, your beverage should remain unsweetened, as any sugar you add to it will only hinder your progress. 

Dark Chocolate and Cocoa

If you have a sweet tooth and abandoning your favorite sugary treats fills you with dread, you can substitute them with small amounts of dark chocolate or cocoa powder. 

Though tasty and full of health benefits, such foods can have a higher concentration of carbohydrates, so it’s a good idea to pay attention to what -and how much- you’re eating. 

Is a Ketogenic Diet Safe?

If there’s one question we get asked more than any other here at Ketolog, it’s whether the diet is safe. 

This is such an important topic that we put together a complete guide called Is Ketosis Dangerous or Safe?

If you don’t have time to read that right now, we can briefly tell you that keto is safe for most people who already enjoy a reasonable level of good health. 

However, there are certain groups of people for whom the diet may not be appropriate. 

Since the diet involves producing higher-than-normal levels of ketone in the liver, those with liver disease should consider alternative weight loss methods, as should anyone with problems with their gallbladder or pancreas. 

If you have diabetes or are pregnant, it’s also best to look at other ways to lose weight.

Keto Diet Pros and Cons: 


  • It can be an excellent way of losing weight. Many people who practice the diet note that not only do they start shedding the pounds days after starting, but they often don’t feel as hungry as they do on other diets. 
  • Although Keto is primarily considered a restrictive diet, it allows you to eat many foods that are off-limits on other diets. Though moderation and healthy eating habits are just as important as ever, you can still enjoy many favorites, like red meat and dairy. 
  • Interest in ketogenic diets as a therapeutic approach for various conditions is high. The diet has been shown to benefit Alzheimer’s patients, those living with chronic pain, and even women with polycystic ovary syndrome (PCOS). 


  • Keto newcomers may experience what’s known as the “Keto Flu,” an illness that typically occurs within the first week of starting a ketogenic diet as the body makes adjustments. Symptoms include nausea, headaches, fatigue, brain fog, and constipation. These symptoms will normally subside pretty quickly, though.
  • Since you’re not eating many fresh fruits, whole grains, and vegetables, you may be depriving your body of essential fibers, vitamins, and minerals, which may cause you to feel physically drained. This can also lead to keto poop symptoms. However, many keto followers add vitamin supplements to their routines to prevent these deficiencies. 

Starting a Ketogenic Diet: What Next? 

With this guide, we’ve strived to arm you with all the information you need to know to help you decide whether keto is the right diet. 

You know what percentage of carbs, fats, and proteins you should consume daily, the best sources to get them from, and what benefits and side effects to expect. 

So, where do you go from here? 

If you’ve taken all that in and you’re ready to get at it, your next step should be to set a start date for your new diet and take stock of what’s in your kitchen. 

Use or donate any food you can’t have, and stock your fridges and cupboards with keto-friendly supplies. 

If you’re concerned about the side effects of a keto diet or whether it’s safe to try with your existing medical conditions, you should consult a medical professional before trying anything new.