The Ketogenic Diet: A Detailed Beginner's Guide to Low-carb Keto Diet - Perfect Keto

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The Ketogenic Diet: The Ultimate Guide to a Low-Carb Keto Diet


The ketogenic diet is a high-fat, low-carb diet that continues to gain popularity as more people recognize its benefits for reaching health and fitness goals.

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You can use this page as your comprehensive guide for everything you need to know about the ketogenic diet and how to get started today.

What Is the Keto Diet?

The purpose of the keto diet is to get your body into ketosis and burn fats instead of carbohydrates for fuel. This diet includes high amounts of fat, adequate amounts of protein, and low levels of carbs.

Typically, the keto diet uses the following macronutrient ratios:

Medical keto diets, such as the ones doctors prescribe for children with epilepsy, are more severe. They usually include approximately 90% fat, 10% protein, and as close to zero carbs as possible[*].

Through the breakdown of macronutrients, you’re able to change how your body uses energy. To fully understand the process, it’s important to grasp how your body uses energy in the first place.


How the Keto Diet Works

When you eat a diet rich in carbohydrates, your body converts those carbs into glucose (blood sugar) which spikes your blood sugar levels.

When blood sugar levels rise, they signal your body to create insulin, a hormone that carries glucose to your cells so that it can be used for energy. This is what is known as an insulin spike[*].

Glucose is your body’s preferred energy source. As long as you keep eating carbohydrates, your body will keep turning them into sugar which is then burned for energy. In other words, when glucose is present, your body will refuse to burn off its fat stores.

Your body starts burning fat by removing carbs. This depletes your glycogen stores (stored glucose), leaving your body no choice but to start burning its fat stores. Your body starts converting fatty acids into ketones, putting your body on a metabolic state known as ketosis[*].

What are Ketones?

In ketosis, your liver converts fatty acids into ketone bodies or ketones. These byproducts become your body’s new energy source. When you decrease your carb intake and replace those calories with healthy fats and carbs, your body responds by becoming keto-adapted, or more efficient at burning fat.

There are three primary ketones:

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In a state of ketosis, ketones take the place of carbs for most purposes[*][*]. Your body also relies on gluconeogenesis, the conversion of glycerol, lactate, and amino acids into glucose, to keep your blood sugar levels from getting dangerously low.

Most importantly, our brains and other organs can use ketones for energy more easily than carbs[*][*]. 

That’s why most people experience increased mental clarity, improved mood, and reduced hunger on keto

These molecules also have antioxidant and anti-inflammatory effects, which means they can help reverse and repair the cellular damage often caused by overeating sugar, for example[*][*].

Ketosis helps your body function on stored body fat when food is not readily available. Similarly, the keto diet focuses on “starving” your body of carbohydrates, switching you into a fat-burning state.

Different Types of Keto Diets

There are four main types of ketogenic diets. Each one takes a slightly different approach to fat vs. carb intake. When deciding which method works best for you, take into account your goals, fitness level, and lifestyle.

Standard Ketogenic Diet (SKD)

This is the most common and recommended version of the keto diet. Here, you stay within 20-50 grams of net carbs per day, focusing on adequate protein intake and high-fat intake.

Targeted Ketogenic Diet (TKD)

If you are an active person, this approach might work best for you. Targeted keto involves eating roughly 25-50 grams of net carbs or less 30 minutes to an hour before exercise.

Cyclical Ketogenic Diet (CKD)

If keto seems intimidating to you, this is an excellent method to start off with. Here, you cycle between periods of eating a low-carb diet for several days, followed by a period of eating high carb (typically lasting several days).

High-Protein Keto Diet

This approach is very similar to the standard (SKD) approach. The primary difference is the protein intake. Here you up your protein intake considerably. This version of the keto diet is more similar to the Atkins diet plan than the others.

Note: The SKD method is the most used and researched version of keto. Therefore, the majority of the information below pertains to this standard method.


How Much Protein, Fat, and Carbs Should You Eat on Keto?

Fat, protein, and carbs are known as macronutrients. In general, the macronutrient breakdown for a keto diet is:

  • Carbs: 5-10%
  • Protein: 20-25%
  • Fat: 75-80% (sometimes more for certain people)

Macronutrients seem to be the cornerstone of any keto diet, but contrary to popular opinion, there is no single macronutrient ratio that works for everyone.

Instead, you’re going to have a completely unique set of macros based on:

  • Physical and mental goals
  • Health history
  • Activity level

The best way to figure out these numbers quickly is to use the free Perfect Keto calculator.


Carb Intake

For most people, a range of 20-50 grams of carbohydrate intake per day is ideal. Some individuals can go as high as 100 grams per day and stay in ketosis.

Protein Intake

To determine how much protein to consume, take into account your body composition, ideal weight, gender, height, and activity level. Ideally, you should consume 0.8 grams of protein per pound of lean body mass. This will prevent muscle loss.

And don’t worry about eating “too much” protein keto — it won’t kick you out ketosis.

Check out the video below by Perfect Keto founder Dr. Anthony Gustin to understand the role protein plays in keto and why gluconeogenesis is not a problem:

Fat Intake

After you calculate the percentage of daily calories that should come from protein and carbs, total the two numbers, and subtract from 100. That number is the percent of calories that should come from fat.

Calorie counting is not required on keto, nor should it be necessary. When you eat a diet high in fat, it’s more satiating than a diet high in carbs and sugar. Generally, this cuts down on your chances of overeating. Instead of counting calories, pay attention to your macro levels.

For further reading, learn more about micronutrients on the keto diet.

What’s the Difference Between Keto and Low-Carb?

The keto diet often gets lumped in with other low-carb diets. However, the main difference between keto and low-carb is the macronutrient levels. In most keto variations, 45% of your calories or more will come from fat, to help transition your body into ketosis. In a low-carb diet, there’s no specified daily intake of fat (or other macronutrients).

The goals between these diets also vary. The goal of keto is to enter ketosis, weaning your body off of burning glucose for fuel long-term. With a low-carb diet, you may never enter ketosis. In fact, some diets cut out carbs in the short-term, then add them back in.

Foods to Eat on the Keto Diet

Now that you understand the basics behind the keto diet, it’s time to make your low-carb food shopping list and hit the grocery store.

On the keto diet, you’ll enjoy nutrient-dense foods and avoid high-carb ingredients.

Meat, Eggs, Nuts, and Seeds

Always choose the highest quality meat you can afford, selecting grass-fed and organic beef whenever possible, wild-caught fish, and pasture-raised poultry, pork, and eggs.

Nuts and seeds are also fine and best eaten raw.

  • Beef: steak, veal, roast, ground beef, and stews
  • Poultry: chicken breasts, quail, duck, turkey and wild game
  • Pork: pork loin, tenderloin, chops, ham, and sugar-free bacon
  • Fish: mackerel, tuna, salmon, trout, halibut, cod, catfish, and mahi-mahi
  • Bone broth: beef bone broth and chicken bone broth
  • Shellfish: oysters, clams, crab, mussels, and lobster
  • Organ meats: heart, liver, tongue, kidney, and offal
  • Eggs: deviled, fried, scrambled, and boiled
  • Lamb
  • Goat
  • Nuts and seeds: macadamia nuts, almonds, and nut butter

Low-Carb Vegetables

Vegetables are a great way to get a healthy dose of micronutrients, thus preventing nutrient deficiencies on keto.

  • Leafy greens, such as kale, spinach, Swiss chard, and arugula
  • Cruciferous vegetables, including cabbage, cauliflower, and zucchini
  • Lettuces, including iceberg, romaine, and butterhead
  • Fermented vegetables like sauerkraut and kimchi
  • Other vegetables such as mushrooms, asparagus, and celery

Keto-Friendly Dairy

Choose the highest quality you can reasonably afford, selecting grass-fed, whole-fat, and organic dairy whenever possible. Avoid low-fat or fat-free dairy products or products with high sugar content.

  • Grass-fed butter and ghee
  • Heavy cream and heavy whipping cream
  • Fermented dairy products like yogurt and kefir
  • Sour cream
  • Hard and soft cheeses

Low-Sugar Fruits

Approach fruit with caution on keto, as it contains high amounts of sugar and carbohydrates.

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  • Avocados (the one fruit that you can enjoy in abundance)
  • Organic berries such as raspberries, blueberries, strawberries, and cranberries (a handful a day)

Healthy Fats and Oils

Healthy fat sources include grass-fed butter, tallow, ghee, coconut oil, olive oil, sustainable palm oil, and MCT oil.

  • Butter and ghee
  • Lard
  • Mayonnaise
  • Coconut oil and coconut butter
  • Flaxseed oil
  • Olive oil
  • Sesame seed oil
  • MCT oil and MCT powder
  • Walnut oil
  • Olive oil
  • Avocado oil

Foods to Avoid on the Keto Diet

It’s best to avoid the following foods on the keto diet due to their high carb content. When starting keto, purge your fridge and cupboards, donate any unopened items, and throw away the rest.


Grains are loaded with carbs, so it’s best to stay away from all grains on keto. This includes whole grains, wheat, pasta, rice, oats, barley, rye, corn, and quinoa.

Beans and Legumes

While many vegans and vegetarians rely on beans for their protein content, these foods are incredibly high-carb. Avoid eating kidney beans, chickpeas, black beans, and lentils.

High-Sugar Fruits

While many fruits are packed with antioxidants and other micronutrients, they’re also high in fructose, which can easily kick you out of ketosis.

Avoid apples, mangoes, pineapples, and other fruits (with the exception of small amounts of berries).

Starchy Veggies

Avoid starchy vegetables like potatoes, sweet potatoes, certain types of squash, parsnips, and carrots.

Like fruit, there are health benefits connected to these foods but they’re also very high in carbs.


This includes but is not limited to desserts, artificial sweeteners, ice cream, smoothies, soda, and fruit juice.

Even condiments such as ketchup and barbecue sauce are usually filled with sugar, so make sure you read the labels before adding them to your meal plan. If you’re craving something sweet, try a keto-friendly dessert recipe made with low-glycemic sweeteners (like stevia or erythritol) instead.


Some alcoholic beverages are low-glycemic and appropriate for the ketogenic diet. However, keep in mind that when you drink alcohol, your liver will preferentially process the ethanol and stop producing ketones.

If you’re on the keto diet to lose weight, keep your alcohol consumption to a minimum. If you’re craving a cocktail, stick to low-sugar mixers and avoid most beer and wine.

Health Benefits of the Keto Diet

The ketogenic diet has been associated with incredible health benefits that stretch way beyond weight loss. Here are just a few ways keto may help you feel better, stronger, and more clear-headed.

Keto for Weight Loss

Probably the main reason that made keto famous: sustainable fat loss. Keto can help significantly decrease body weight, body fat, and body mass while maintaining muscle mass[*].

Keto for Endurance Levels

The ketogenic diet may help improve endurance levels for athletes. However, it may take time for athletes to adjust to burning fat instead of glucose for energy[*].

Keto for Gut Health

Several studies have shown a link between low sugar intake and an improvement in symptoms of irritable bowel syndrome (IBS). One study showed that the ketogenic diet can improve abdominal pain and overall quality of life in those with IBS[*].

Keto for Diabetes

The ketogenic diet may help balance blood glucose and insulin levels. The decreased risk of insulin resistance can help prevent metabolic diseases like type 2 diabetes[*].

Keto for Heart Health

The keto diet can help reduce risk factors for heart disease, including improvement in HDL cholesterol levels, blood pressure, triglycerides, and LDL cholesterol (related to plaque in the arteries)[*].

Keto for Brain Health

Ketone bodies have been linked to possible neuroprotective and anti-inflammatory benefits. Therefore, the keto diet may support those with conditions such as Parkinson’s and Alzheimer’s diseases, among other degenerative brain conditions[*][*].

Keto for Epilepsy

The ketogenic diet was created in the early 20th century to help prevent seizures in epileptic patients, especially children. To this day, ketosis is used as a therapeutic method for those who suffer from epilepsy[*].

Keto for PMS

An estimated 90% of women experience one or more symptoms associated with PMS[*][*].

The keto diet can help balance blood sugar, combat chronic inflammation, boost nutrient stores, and crush cravings — all of which may help alleviate PMS symptoms[*][*].

How to Know When You’re In Ketosis

Ketosis can be a gray area, as there are varying degrees of it. In general, it can often take around 1-3 days to reach full ketosis.

The best way to monitor your ketone levels is through testing, which you can do from home. When you eat on the ketogenic diet, excess ketones spill over into several areas of the body. This allows you to measure your ketone levels in various ways:

  • In your urine with a test strip
  • In your blood with a glucose meter
  • On your breath with a breath meter

Each method has its advantages and disadvantages, but measuring ketones in your blood is often the most effective. Although it’s the most affordable, urine testing is typically the least accurate method.

Supplements to Support the Keto Diet

Supplements are a popular way to maximize the benefits of the ketogenic diet. Adding these supplements alongside a healthy, whole-food keto diet plan can help you feel your best while supporting your health goals.

Exogenous Ketones

Exogenous ketones are supplemental ketones — usually beta-hydroxybutyrate or acetoacetate — that help give you that extra boost of energy. You can take exogenous ketones in between meals or for a quick burst of energy before a workout.

MCT Oil and Powder

MCTs (or medium-chain triglycerides) are a type of fatty acid that your body can convert to energy quickly and efficiently. MCTs are extracted from coconuts and are sold mostly in liquid or powder form.

Collagen Protein

Collagen is the most abundant protein in your body, supporting the growth of joints, organs, hair, and connective tissues. Amino acids from collagen supplements may also help with energy production, DNA repair, detox, and healthy digestion[*].

Micronutrient Supplements

Keto Micro Greens provides all your micronutrients in one convenient scoop. Each serving size contains 14 servings of 22 different fruits and vegetables, plus herbs and MCT fats to assist with absorption.

Whey Protein

Whey supplements are some of the best-studied supplements for weight loss support, muscle gain, and recovery[*][*]. Make sure to choose grass-fed whey only and avoid powders with sugar or any other additives that could spike blood sugar.


Electrolyte balance is one of the most critical — yet most overlooked — components of a successful keto diet experience. Being keto can make you excrete more electrolytes than usual, so you have to replenish them yourself — a fact few know about when starting their keto journey[*].

Add more sodium, potassium, and calcium to your diet or grab a supplement that can help support your body.

Is the Keto Diet Safe?

Ketosis is safe and a natural metabolic state. But it’s often confused with a highly dangerous metabolic state called ketoacidosis, which is commonly seen in people with diabetes[*].

Having ketone levels in the 0.5-5.0mmol/L range isn’t dangerous, but it may cause a range of harmless issues known as the “keto flu.”

Keto Flu Symptoms

Many people have to deal with common short-term side effects similar to flu symptoms as they become fat adapted. These temporary symptoms are byproducts of dehydration and low carbohydrate levels while your body adjusts. They can include:

  • Headaches
  • Lethargy
  • Nausea
  • Brain fog
  • Stomach pain
  • Low motivation

The symptoms of keto flu can often be shortened by taking ketone supplements, which can help make the transition into ketosis much easier.

Sample Keto Diet Meal Plans With Recipes

If you want to take all the guesswork out of going keto, meal plans are an excellent option. 

Because you aren’t faced with dozens of decisions every day, meal plans with recipes can also make your new diet less overwhelming.

You can use our Keto Meal Plan For Beginners as a quick start guide. 

Keto Diet Explained: Get Started on Keto

If you’ve tried the ketogenic diet before and didn’t make it past the first few days or weeks, this 30-day guided program is for you. If you’re on the keto diet right now and have hit a slump or plateau, you should also try this program.

The Keto Kickstart includes:

  • Tips and tools on how to get into and stay in ketosis
  • Shopping lists
  • Easy, family-friendly keto recipes
  • Simple lessons on how ketosis actually works
  • Tips on figuring out if you’re in ketosis and how to track your progress

If your curious about the ketogenic diet and would like to learn more about this lifestyle followed by thousands of people, check out these articles that offer lots of useful, easy-to-follow information.

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