The Ketogenic Diet: A Detailed Beginner’s Guide to Keto
ketogenic diet
beginner's guide to keto
Rudy Mawer, MSc, CISSN Rudy Mawer
The ketogenic diet (keto) is a low-carb, high-fat diet that causes weight loss and provides numerous health benefits. This is a detailed beginner's guide.
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The ketogenic diet involves consuming a very low amount of carbohydrates and replacing them with fat to help your body burn fat for energy. Health benefits can include weight loss and lowering your risk for certain diseases.

The ketogenic diet (or keto diet, for short) is a low carb, high fat diet that offers many health benefits.

In fact, many studies show that this type of diet can help you lose weight and improve your health (1).

Ketogenic diets may even have benefits against diabetes, cancer, epilepsy, and Alzheimer’s disease (2, 3, 4, 5).

Here is a detailed beginner’s guide to the keto diet.

Keto basics

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 (6).

Ketogenic diets can cause significant reductions in blood sugar and insulin levels. This, along with the increased ketones, has some health benefits (6, 7, 8).

SUMMARY

The keto diet is a low carb, high fat diet. It lowers blood sugar and insulin levels and shifts the body’s metabolism away from carbs and toward fat and ketones.

There are several versions of the ketogenic diet, and what you eat depends on the type. They include:

Standard ketogenic diet (SKD): This is a very low carb, moderate protein and high fat diet. It typically contains 70% fat, 20% protein, and only 10% carbs (9).

Cyclical ketogenic diet (CKD): This diet involves periods of higher carb refeeds, such as 5 ketogenic days followed by 2 high carb days.

Targeted ketogenic diet (TKD): This diet allows you to add carbs around workouts.

High protein ketogenic diet: This is similar to a standard ketogenic diet, but includes more protein. The ratio is often 60% fat, 35% protein, and 5% carbs.

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.

The information in this article mostly applies to the standard ketogenic diet (SKD), although many of the same principles also apply to the other versions.

SUMMARY

There are several versions of the keto diet. The standard (SKD) version is the most researched and most recommended.

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 (6).

It’s also important to moderate your protein consumption. This is because protein can be converted into glucose if consumed in high amounts, which may slow your transition into ketosis (10).

Practicing intermittent fasting could also help you enter ketosis faster. There are many different forms of intermittent fasting, but the most common method involves limiting food intake to around 8 hours per day and fasting for the remaining 16 hours (11).

Blood, urine, and breath tests are available, which can help determine whether you’ve entered ketosis by measuring the amount of ketones produced by your body.

Certain symptoms may also indicate that you’ve entered ketosis, including increased thirst, dry mouth, frequent urination, and decreased hunger or appetite (12).

SUMMARY

Ketosis is a metabolic state in which your body uses fat for fuel instead of carbs. Modifying your diet and practicing intermittent fasting can help you enter ketosis faster. Certain tests and symptoms can also help determine whether you’ve entered ketosis.

A ketogenic diet is an effective way to lose weight and lower risk factors for disease (1, 2, 3, 4, 5).

In fact, research shows that the ketogenic diet may be as effective for weight loss as a low fat diet (13, 14, 15).

What’s more, the diet is so filling that you can lose weight without counting calories or tracking your food intake (16).

One review of 13 studies found that following a very low carb, ketogenic diet was slightly more effective for long-term weight loss than a low fat diet. People who followed the keto diet lost an average of 2 pounds (0.9 kg) more than the group that followed a low fat diet (13).

What’s more, it also led to reductions in diastolic blood pressure and triglyceride levels (13).

Another study in 34 older adults found that those who followed a ketogenic diet for 8 weeks lost nearly five times as much total body fat as those who followed a low fat diet (17).

The increased ketones, lower blood sugar levels, and improved insulin sensitivity may also play a key role (18, 19).

For more details on the weight loss effects of a ketogenic diet, read this article.

SUMMARY

A ketogenic diet can help you lose slightly more weight than a low fat diet. This often happens with less hunger.

Discover more about this condition

Diabetes is characterized by changes in metabolism, high blood sugar, and impaired insulin function (20).

The ketogenic diet can help you lose excess fat, which is closely linked to type 2 diabetes, prediabetes, and metabolic syndrome (21, 22, 23, 24).

One older study found that the ketogenic diet improved insulin sensitivity by a whopping 75% (25).

A small study in women with type 2 diabetes also found that following a ketogenic diet for 90 days significantly reduced levels of hemoglobin A1C, which is a measure of long-term blood sugar management (26).

Another study in 349 people with type 2 diabetes found that those who followed a ketogenic diet lost an average of 26.2 pounds (11.9 kg) over a 2-year period. This is an important benefit when considering the link between weight and type 2 diabetes (24, 27).

What’s more, they also experienced improved blood sugar management, and the use of certain blood sugar medications decreased among participants throughout the course of the study (27).

For more information, check out this article on the benefits of low carb diets for people with diabetes.

SUMMARY

The ketogenic diet can boost insulin sensitivity and cause fat loss, leading to significant health benefits for people with type 2 diabetes or prediabetes.

The ketogenic diet actually originated as a tool for treating neurological diseases such as epilepsy.

Studies have now shown that the diet can have benefits for a wide variety of different health conditions:

Heart disease. The ketogenic diet can help improve risk factors like body fat, HDL (good) cholesterol levels, blood pressure, and blood sugar (28, 29).

Cancer. The diet is currently being explored as an additional treatment for cancer, because it may help slow tumor growth. (4, 30, 31).

Alzheimer’s disease. The keto diet may help reduce symptoms of Alzheimer’s disease and slow its progression (5, 32, 33).

Epilepsy. Research has shown that the ketogenic diet can cause significant reductions in seizures in epileptic children (3).

Parkinson’s disease. Although more research is needed, one study found that the diet helped improve symptoms of Parkinson’s disease (34).

Polycystic ovary syndrome. The ketogenic diet can help reduce insulin levels, which may play a key role in polycystic ovary syndrome (35, 36).

Brain injuries. Some research suggests that the diet could improve outcomes of traumatic brain injuries (37).

However, keep in mind that research into many of these areas is far from conclusive.

SUMMARY

A ketogenic diet may provide many health benefits, especially with metabolic, neurological, or insulin-related diseases.

Any food that’s high in carbs should be limited.

Here’s a list of foods that need to be reduced or eliminated on a ketogenic diet:

sugary foods: soda, fruit juice, smoothies, cake, ice cream, candy, etc.

grains or starches: wheat-based products, rice, pasta, cereal, etc.

fruit: all fruit, except small portions of berries like strawberries

beans or legumes: peas, kidney beans, lentils, chickpeas, etc.

root vegetables and tubers: potatoes, sweet potatoes, carrots, parsnips, etc.

low fat or diet products: low fat mayonnaise, salad dressings, and condiments

some condiments or sauces: barbecue sauce, honey mustard, teriyaki sauce, ketchup, etc.

unhealthy fats: processed vegetable oils, mayonnaise, etc.

alcohol: beer, wine, liquor, mixed drinks

sugar-free diet foods: sugar-free candies, syrups, puddings, sweeteners, desserts, etc.

SUMMARY

Avoid carb-based foods like grains, sugars, legumes, rice, potatoes, candy, juice, and even most fruits.

You should base the majority of your meals around these foods:

meat: red meat, steak, ham, sausage, bacon, chicken, and turkey

fatty fish: salmon, trout, tuna, and mackerel

eggs: pastured or omega-3 whole eggs

butter and cream: grass-fed butter and heavy cream

cheese: unprocessed cheeses like cheddar, goat, cream, blue, or mozzarella

nuts and seeds: almonds, walnuts, flaxseeds, pumpkin seeds, chia seeds, etc.

healthy oils: extra virgin olive oil, and avocado oil

avocados: whole avocados or freshly made guacamole

low carb veggies: green veggies, tomatoes, onions, peppers, etc.

condiments: salt, pepper, herbs, and spices

It’s best to base your diet mostly on whole, single-ingredient foods. Here’s a list of 44 healthy low carb foods.

SUMMARY

Base the majority of your diet on foods such as meat, fish, eggs, butter, nuts, healthy oils, avocados, and plenty of low carb veggies.

To help get you started, here’s a sample ketogenic diet meal plan for one week:

Monday

breakfast: veggie and egg muffins with tomatoes

lunch: chicken salad with olive oil, feta cheese, olives, and a side salad

dinner: salmon with asparagus cooked in butter

Tuesday

breakfast: egg, tomato, basil, and spinach omelet

lunch: almond milk, peanut butter, spinach, cocoa powder, and stevia milkshake (more keto smoothies here) with a side of sliced strawberries

dinner: cheese-shell tacos with salsa

Wednesday

breakfast: nut milk chia pudding topped with coconut and blackberries

lunch: avocado shrimp salad

dinner: pork chops with Parmesan cheese, broccoli, and salad

Thursday

breakfast: omelet with avocado, salsa, peppers, onion, and spices

lunch: a handful of nuts and celery sticks with guacamole and salsa

dinner: chicken stuffed with pesto and cream cheese, and a side of grilled zucchini

Friday

breakfast: sugar-free Greek, whole milk yogurt with peanut butter, cocoa powder, and berries

lunch: ground beef lettuce wrap tacos with sliced bell peppers

dinner: loaded cauliflower and mixed veggies

Saturday

breakfast: cream cheese pancakes with blueberries and a side of grilled mushrooms

lunch: Zucchini and beet “noodle” salad

dinner: white fish cooked in olive oil with kale and toasted pine nuts

Sunday

breakfast: fried eggs with and mushrooms

lunch: low carb sesame chicken and broccoli

dinner: spaghetti squash Bolognese

Always try to rotate the vegetables and meat over the long term, as each type provides different nutrients and health benefits.

For tons of recipes, check out these 101 healthy low carb recipes and this keto shopping list.

SUMMARY

You can eat a wide variety of tasty and nutritious meals on a ketogenic diet. It’s not all meats and fats. Vegetables are an important part of the diet.

In case you get hungry between meals, here are some healthy, keto-approved snacks:

fatty meat or fish

cheese

a handful of nuts or seeds

keto sushi bites

olives

one or two hard-boiled or deviled eggs

keto-friendly snack bars

90% dark chocolate

full-fat Greek yogurt mixed with nut butter and cocoa powder

bell peppers and guacamole

strawberries and plain cottage cheese

celery with salsa and guacamole

beef jerky

smaller portions of leftover meals

fat bombs

SUMMARY

Great snacks for a keto diet include pieces of meat, cheese, olives, boiled eggs, nuts, raw veggies, and dark chocolate.

Although getting started on the ketogenic diet can be challenging, there are several tips and tricks that you can use to make it easier.

Start by familiarizing yourself with food labels and checking the grams of fat, carbs, and fiber to determine how your favorite foods can fit into your diet.

Planning out your meals in advance may also be beneficial and can help you save extra time throughout the week.

Many websites, food blogs, apps, and cookbooks also offer keto-friendly recipes and meal ideas that you can use to build your own custom menu.

Alternatively, some meal delivery services even offer keto-friendly options for a quick and convenient way to enjoy keto meals at home.

Look into healthy frozen keto meals when you’re short on time

When going to social gatherings or visiting family and friends, you may also want to consider bringing your own food, which can make it much easier to curb cravings and stick to your meal plan.

SUMMARY

Reading food labels, planning your meals ahead, and bringing your own foods when visiting family and friends can make it much easier to stick to the ketogenic diet.

Many restaurant meals can be made keto-friendly.

Most restaurants offer some kind of meat or fish-based dish. Order this and replace any high carb food with extra vegetables.

Egg-based meals are also a great option, such as an omelet or eggs and bacon.

Another favorite is bun-less burgers. You could also swap the fries for vegetables instead. Add extra avocado, cheese, bacon, or eggs.

At Mexican restaurants, you can enjoy any type of meat with extra cheese, guacamole, salsa, and sour cream.

For dessert, ask for a mixed cheese board or berries with cream.

SUMMARY

When eating out, select a meat-, fish-, or egg-based dish. Order extra veggies instead of carbs or starches, and have cheese for dessert.

Although the ketogenic diet is usually safe for most healthy people, there may be some initial side effects while your body adapts.

There’s some anecdotal evidence of these effects often referred to as the keto flu (38). Based on reports from some on the eating plan, it’s usually over within a few days.

Reported keto flu symptoms include diarrhea, constipation, and vomiting (39). Other less common symptoms include:

poor energy and mental function

increased hunger

sleep issues

nausea

digestive discomfort

decreased exercise performance

To minimize this, you can try a regular low carb diet for the first few weeks. This may teach your body to burn more fat before you completely eliminate carbs.

A ketogenic diet can also change the water and mineral balance of your body, so adding extra salt to your meals or taking mineral supplements may help. Talk to your doctor about your nutritional needs.

At least in the beginning, it’s important to eat until you’re full and avoid restricting calories too much. Usually, a ketogenic diet causes weight loss without intentional calorie restriction.

SUMMARY

Many of the side effects of starting a ketogenic diet can be limited. Easing into the diet and taking mineral supplements can help.

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

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 (40, 41).

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.

SUMMARY

There are some side effects to the keto diet about which you should speak to your doctor if you plan to stay on the diet long term.

Here are answers to some of the most common questions about the ketogenic diet.

Can I ever eat carbs again?

Yes. However, it’s important to significantly reduce your carb intake initially. After the first 2 to 3 months, you can eat carbs on special occasions — just return to the diet immediately after.

Will I lose muscle?

There’s a risk of losing some muscle on any diet. However, protein intake and high ketone levels may help minimize muscle loss, especially if you lift weights (50, 51).

Can I build muscle on a ketogenic diet?

Yes, but it may not work as well as on a moderate carb diet (52, 53). For more details about low carb or keto diets and exercise performance, read this article.

How much protein can I eat?

Protein should be moderate, as a very high intake can spike insulin levels and lower ketones. Around 35% of total calorie intake is probably the upper limit.

What if I am constantly tired, weak, or fatigued?

You may not be in full ketosis or be utilizing fats and ketones efficiently. To counter this, lower your carb intake and revisit the points above. A supplement like MCT oil or ketones may also help (42, 43).

My urine smells fruity. Why is this?

Don’t be alarmed. This is simply due to the excretion of by-products created during ketosis (54).

My breath smells. What can I do?

This is a common side effect. Try drinking naturally flavored water or chewing sugar-free gum.

I heard ketosis was extremely dangerous. Is this true?

People often confuse ketosis with ketoacidosis. Ketoacidosis is dangerous, but ketosis on a ketogenic diet is usually fine for healthy people. Speak to your doctor before starting any new diet.

I have digestion issues and diarrhea. What can I do?

This common side effect usually passes after 3 to 4 weeks. If it persists, try eating more high fiber veggies (55, 56).

What is the difference between a keto and a ketogenic diet?

People often refer to the ketogenic diet colloquially as the keto diet, so these terms refer to the same thing.

How much weight can I lose in 1 week on keto?

In the first week of the keto diet, the weight you lose is typically water weight. Anecdotally, people report losing about 1 lb (0.5 kg) to 10 lb or more (5 kg).

Learn more about weight loss after 1 week on keto.

Is keto good or bad for you?

A ketogenic diet can be great for people who:

are overweight

have diabetes

are looking to improve their metabolic health

It may be less suitable for elite athletes or those wishing to add large amounts of muscle or weight.

It may also not be sustainable for some people’s lifestyles and preferences. Speak with your doctor about your eating plan and goals to decide if a keto eating plan is right for you.

While following the ketogenic diet, you reduce your carbohydrate intake and replace it with healthy fats. This can help your body to use fat for energy, encouraging weight loss and possibly reducing the chance of developing certain health issues.

That said, consult your doctor prior to engaging in the diet for an extended period of time, as it may have some side effects. More research is needed to understand its long-term effect on the body.

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