The keto diet is a low carb, high fat diet that puts the body into a metabolic state called ketosis. It involves drastically reducing carb intake and replacing it with fat to lower blood sugar and insulin levels and shift metabolism away from carbs and toward fat and ketones. Several versions of the keto diet exist, but the standard version is the most researched and recommended. Entering ketosis requires limiting carbs to 20-50g per day through diet and intermittent fasting. Potential benefits include weight loss, improved blood sugar control for diabetes, reduced risk factors for heart disease and cancer, and better management of neurological conditions like epilepsy.

1. NUTRITION
The Ketogenic Diet: A Detailed
Beginner’s Guide to Keto
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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 
).
u
u Evidence Based
Evidence Based
What It Is Diet types Ketosis Weight loss Diabetes Other benefits
Foods to avoid Foods to eat Sample plan Snacks Tips Dining out
Side effects Risks Supplements FAQs Bottom line
What is a ketogenic diet?
Written by Rudy Mawer,
MSc, CISSN — Medically
reviewed by Amy Richter,
RD — Updated on October
22, 2020
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2. 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, including:
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
Different types of ketogenic diets
What is ketosis?
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3. 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.
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.
Ketogenic diets can help you lose weight
Ketogenic diets for diabetes and
prediabetes
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4. 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
Other health benefits of keto
Foods to avoid
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5. 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, coconut 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
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Foods to eat
A sample keto meal plan for 1 week
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6. 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 coconut 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
Healthy keto snacks
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7. 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.
Keto tips and tricks
Tips for eating out on a ketogenic diet
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8. MCT oil. Added to drinks or yogurt, MCT oil provides energy and helps increase ketone
levels. Shop for MCT oil online (42 
, 43 
).
Minerals. Added salt and other minerals can be important when starting out due to shifts in
water and mineral balance (44 
).
Caffeine. Caffeine can have benefits for energy, fat loss, and performance (45).
Exogenous ketones. This supplement may help raise the body’s ketone levels (46 
).
Creatine. Creatine provides numerous benefits for health and performance. This can help
if you are combining a ketogenic diet with exercise (47 
).
Whey. Use half a scoop of whey protein in shakes or yogurt to increase your daily protein
intake (48
, 49 
). Shop for tasty whey products on online.
SUMMARY
Certain supplements can be beneficial on a ketogenic diet. These include exogenous
ketones, MCT oil, and minerals.
Here are answers to some of the most common questions about the ketogenic diet.
1. 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.
2. 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 
).
3. 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.
4. 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.
5. 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 
).
6. 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 
).
7. My breath smells. What can I do?
This is a common side effect. Try drinking naturally flavored water or chewing sugar-free gum.
8. I heard ketosis was extremely dangerous. Is this true?
People often confuse ketosis with ketoacidosis. Ketoacidosis is dangerous, but the ketosis on a
ketogenic diet is usually fine for healthy people. Speak to your doctor before starting any new
diet.
9. I have digestion issues and diarrhea. What can I do?
Frequently asked questions

9. Last medically reviewed on October 21, 2020
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