A Detailed Beginner’s Guide to The Ketogenic Diet

The ketogenic eating plan involves eating very few carbohydrates and substituting them with fats so your body burns fat for fuel. Potential health advantages include shedding pounds and lowering the risk of certain illnesses.

The ketogenic diet (often called the keto diet) is a low-carb, high-fat nutritional approach that offers numerous health perks.

Indeed, many studies indicate this style of eating can promote weight loss and enhance overall health.

Ketogenic regimens may even offer benefits for conditions like diabetes, cancer, epilepsy, and Alzheimer’s disease.

Continue reading to get everything a beginner needs to know about the keto diet.

What are the basic rules for keto?

Keto basics

The ketogenic diet is an extremely low-carb, high-fat approach that resembles Atkins and other low-carb diets.

It requires drastically cutting carbohydrate intake and replacing those calories with fat. This drop in carbs triggers a metabolic state called ketosis.

In ketosis, your body becomes very efficient at using fat for energy. The liver also converts fat into ketones, which can be an energy source for the brain.

Ketogenic diets can lead to notable decreases in blood glucose and insulin levels. These changes, together with increased ketone production, may offer several health benefits.

SUMMARY

The keto diet emphasizes low carbs and high fat. It reduces blood sugar and insulin and shifts metabolism from carbs to fats and ketones.

What can I eat on the keto diet?

There are multiple versions of the ketogenic diet, and what you consume depends on the variant. These include:

• Standard ketogenic diet (SKD): A very low-carb, moderate-protein, high-fat plan. Typical macros are about 70% fat, 20% protein, and 10% carbs.
• Cyclical ketogenic diet (CKD): Involves periodic higher-carb refeed days, for example 5 days of keto followed by 2 high-carb days.
• Targeted ketogenic diet (TKD): Allows extra carbs around workout times.
• High-protein ketogenic diet: Similar to the standard version but with more protein—often around 60% fat, 35% protein, and 5% carbs.

Of these, only the standard and high-protein versions have been researched extensively. Cyclical and targeted approaches are more advanced and often used by athletes and bodybuilders.

The guidance in this article mostly applies to the standard ketogenic diet (SKD), although many principles overlap with the other styles.

SUMMARY

There are several keto variations. The standard (SKD) approach is the most studied and usually recommended.

What is ketosis?

Ketosis is a metabolic state in which your body relies on fat instead of carbohydrates for energy.

It happens when you greatly lower carbohydrate intake, reducing your body’s supply of glucose—the primary energy source for cells.

Following a ketogenic diet is the most reliable way to reach ketosis. This generally means keeping carbs around 20–50 grams per day and increasing consumption of fats like meat, fish, eggs, nuts, and healthy oils.

It’s also important to keep protein moderate, since excess protein can convert to glucose and may delay getting into ketosis.

Intermittent fasting can also speed up the transition to ketosis. There are many fasting methods, but a common one is eating within an 8-hour window and fasting for the other 16 hours.

There are blood, urine, and breath tests to check ketone levels and confirm ketosis.

Some signs that you’ve entered ketosis include increased thirst, dry mouth, frequent urination, and reduced appetite.

SUMMARY

Ketosis is when your body uses fat for fuel instead of carbs. Adjusting your diet and practicing intermittent fasting can hasten ketosis. Tests and certain symptoms can indicate you’re in ketosis.

Can the keto diet help me lose weight?

The ketogenic diet is an effective strategy for weight loss and for reducing disease risk factors.

Research suggests the keto diet can be as effective for weight loss as low-fat diets.

Additionally, the diet tends to be very satiating, allowing weight loss without meticulous calorie counting.

A review of 13 studies found that a very low-carb ketogenic diet produced slightly greater long-term weight loss than a low-fat diet. Those on keto lost on average about 2 pounds (0.9 kg) more than the low-fat group.

It also resulted in reductions in diastolic blood pressure and triglyceride levels.

Another trial in 34 older adults showed participants on a ketogenic diet for 8 weeks lost nearly five times more total body fat than those on a low-fat diet.

Raised ketone levels, lower blood glucose, and improved insulin sensitivity likely contribute to these effects.

For more detail on keto’s weight-loss effects, see this article.

SUMMARY

The ketogenic diet can help you lose a bit more weight than a low-fat plan, often with reduced hunger.

Discover more about Type 2 Diabetes

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Is the keto diet good for people with diabetes and prediabetes?

Diabetes is marked by metabolic disturbances, high blood glucose, and impaired insulin function.

The ketogenic diet can assist in losing excess fat, which is closely tied to type 2 diabetes, prediabetes, and metabolic syndrome.

An older study reported that the ketogenic diet improved insulin sensitivity by about 75%.

A small trial in women with type 2 diabetes found that a 90-day ketogenic diet significantly lowered hemoglobin A1C, a marker of long-term blood sugar control.

Another study of 349 people with type 2 diabetes showed those on a ketogenic diet lost an average of 26.2 pounds (11.9 kg) over two years—a notable improvement given the link between weight and diabetes.

Participants also had better blood sugar control and many were able to reduce certain diabetes medications during the study.

For more, read this article on the advantages of low-carb diets for people with diabetes.

SUMMARY

The ketogenic diet can improve insulin sensitivity and promote fat loss, offering important benefits for people with type 2 diabetes or prediabetes.

»MORE:Living with diabetes? Explore our top resources.

What are the other benefits of the keto diet?

The ketogenic diet was originally developed as a treatment for neurological disorders such as epilepsy.

Research now suggests the diet may benefit a range of health conditions:

• Heart disease. Keto may improve risk markers like body fat, HDL (good) cholesterol, blood pressure, and blood sugar.
• Cancer. It’s being investigated as an adjunct cancer therapy because it might slow tumor progression..
• Alzheimer’s disease. The diet may help alleviate symptoms and slow progression of Alzheimer’s.
• Epilepsy. Studies show the ketogenic diet can greatly reduce seizures in children with epilepsy.
• Parkinson’s disease. While more research is necessary, one study found symptom improvements with the diet.
• Polycystic ovary syndrome. Keto can lower insulin levels, which may be beneficial for PCOS.
• Brain injuries. Some evidence suggests the diet might improve recovery from traumatic brain injuries.

Keep in mind that research in many of these areas is still preliminary.

SUMMARY

The ketogenic diet may offer many health advantages, especially for metabolic, neurological, and insulin-related conditions.

What foods do I avoid on a keto diet?

Foods high in carbohydrates should be minimized.

Here’s a list of items to cut back on or avoid while following keto:

• sugary foods: soda, fruit juices, smoothies, cakes, ice cream, candy, etc.
• grains and starches: wheat-based goods, rice, pasta, cereal, etc.
• fruit: most fruit, except small portions of berries or strawberries
• beans and 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, reduced-fat dressings, and light condiments
• some sauces and condiments: barbecue sauce, honey mustard, teriyaki, ketchup, etc.
• unhealthy fats: processed vegetable oils, margarine, etc.
• alcohol: beer, wine, mixed drinks
• sugar-free diet foods: sugar-free candies, syrups, puddings, sweeteners, desserts, etc.

SUMMARY

Avoid carb-heavy foods like grains, sugars, legumes, rice, potatoes, sweets, juices, and most fruits.

What foods can I eat on the keto diet?

You should center most meals around the following 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 fresh guacamole
• low-carb vegetables: green vegetables, tomatoes, onions, peppers, etc.
• condiments: salt, pepper, herbs, and spices

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

SUMMARY

Base most of your diet on foods such as meat, fish, eggs, butter, nuts, healthy oils, avocados, and plenty of low-carb vegetables.

A sample keto meal plan for 1 week

To help you begin, here’s a sample one-week ketogenic meal plan:

Monday

• breakfast:veggie and egg muffins with tomatoes
• lunch: chicken salad with olive oil, feta, 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 shake (more keto smoothies here) with 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, broccoli, and salad

Thursday

• breakfast: omelet with avocado, salsa, peppers, onion, and spices
• lunch: a handful of nuts and celery with guacamole and salsa
• dinner: chicken stuffed with pesto and cream cheese, served with 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 with 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 mushrooms
• lunch: low-carb sesame chicken with broccoli
• dinner: spaghetti squash Bolognese

Try to rotate vegetables and proteins over time, as each provides different nutrients and health advantages.

For many recipes, see these 101 healthy low-carb recipes and this keto shopping list.

SUMMARY

You can enjoy a wide variety of tasty, nutritious meals on keto. It’s not just meats and fats—vegetables play a key role.

Healthy keto snacks

If you feel hungry between meals, here are some keto-friendly snack ideas:

• 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 with guacamole
• strawberries with plain cottage cheese
• celery with salsa and guacamole
• beef jerky
• small portions of leftover meals
• fat bombs

SUMMARY

Good keto snacks include pieces of meat, cheese, olives, eggs, nuts, raw veggies, and dark chocolate.

Keto tips and tricks

Starting a ketogenic diet can be challenging, but these tips can make it easier.

• Begin by learning how to read nutrition labels and check grams of fat, carbs, and fiber to see how foods fit your plan.
• Planning meals ahead of time can save time and help you stay on track throughout the week.
• Many websites, blogs, apps, and cookbooks provide keto-friendly recipes and meal ideas you can use to craft your menu.
• Some meal delivery services also offer keto options for a quick, convenient way to enjoy keto meals at home.
• Consider healthy frozen keto meals when time is tight.
• When attending social events or visiting friends and family, bringing your own food can make it easier to resist temptations and stick with your plan.

SUMMARY

Reading labels, planning meals, and bringing your own dishes to gatherings can help you adhere to the ketogenic diet more easily.

Tips for eating out on a ketogenic diet

Many restaurant dishes can be adapted to be keto-friendly.

Most places offer a meat- or fish-based entrée. Order that and swap high-carb sides for extra vegetables.

Egg-based dishes like omelets or eggs and bacon are also good choices.

Bunless burgers are another great option—replace fries with veggies and add avocado, cheese, bacon, or eggs.

At Mexican restaurants, enjoy meats with extra cheese, guacamole, salsa, and sour cream.

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

SUMMARY

When dining out, pick a meat-, fish-, or egg-based meal. Replace carbs with vegetables and choose cheese or berries for dessert.

Side effects and how to minimize them

Although generally safe for many healthy people, the ketogenic diet can cause initial side effects as your body adjusts.

There are anecdotal reports of symptoms often called the “keto flu”. Most people say it resolves within a few days.

Commonly reported keto flu effects include diarrhea, constipation, and nausea. Other, less frequent symptoms include:

• reduced energy and mental clarity
• increased hunger
• sleep disturbances
• nausea
• digestive discomfort
• reduced exercise performance

To reduce these effects, you might ease into keto by following a regular low-carb diet for the first few weeks. This helps your body adapt to burning more fat before fully eliminating carbs.

Keto can also alter your body’s water and mineral balance, so adding extra salt to meals or taking mineral supplements may help. Discuss your needs with your doctor.

At least initially, eat until you’re satisfied and avoid severe calorie restriction. Typically, keto leads to weight loss without intentionally limiting calories.

SUMMARY

Many starting symptoms of keto can be managed. Gradually transitioning and taking mineral supplements may reduce side effects.

Does being on the keto diet have any risks?

Although keto has benefits, long-term adherence may carry some risks, including:

• low blood protein
• increased fat in the liver
• kidney stones
• micronutrient deficiencies

People taking sodium-glucose cotransporter 2 (SGLT2) inhibitors for type 2 diabetes have a higher risk of diabetic ketoacidosis, a serious condition that raises blood acidity. Those on this medication should avoid the keto diet.

Ongoing research is exploring long-term safety. Keep your doctor informed about your eating plan so they can advise you.

SUMMARY

There are potential risks to long-term keto use; talk to your doctor if you plan to follow it for an extended period.

Are there supplements for a keto diet?

No supplements are required, but some can be helpful.

• MCT oil. Added to drinks or yogurt, MCT oil supplies energy and can boost ketone levels. Shop for MCT oil online.
• Minerals. Extra salt and other minerals can be important when starting due to shifts in fluid and mineral balance.
• Caffeine. Caffeine may improve energy, fat loss, and performance (45).
• Exogenous ketones. These supplements may help raise circulating ketone levels.
• Creatine. Creatine offers benefits for health and exercise performance and can be useful if you combine keto with training.
• Whey. Half a scoop of whey protein in shakes or yogurt can bump up daily protein intake. Shop for whey products online.

SUMMARY

Certain supplements may be useful on keto, including MCT oil, exogenous ketones, and minerals.

Frequently asked questions

Below are answers to common questions about the ketogenic diet.

Can I ever eat carbs again?

Yes. However, you should drastically cut carbs initially. After 2–3 months, you can have carbs on special occasions—just return to keto afterward.

Will I lose muscle?

Any diet carries some muscle-loss risk. Adequate protein and high ketone levels may help preserve muscle, especially when combined with resistance training.

Can I build muscle on a ketogenic diet?

Yes, but it may be less optimal than a moderate-carb diet. For more on low-carb diets and exercise, see this article.

How much protein can I eat?

Protein should be moderate—very high amounts can raise insulin and reduce ketones. About 35% of calories is likely an upper limit.

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

You might not be fully in ketosis or efficiently using fat and ketones. Lower carbs and revisit the suggestions above. Supplements like MCT oil or ketones may help.

My urine smells fruity. Why is this?

There’s no need to worry. It’s caused by excreted by-products produced during ketosis.

My breath smells. What can I do?

Bad breath is common. Try drinking flavored water or chewing sugar-free gum.

I heard ketosis was extremely dangerous. Is this true?

Ketosis is often confused with ketoacidosis. Ketoacidosis is dangerous, but dietary ketosis is usually safe for healthy people. Talk with your doctor before starting any new diet.

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

This often resolves within 3–4 weeks. If it persists, try eating more fiber-rich vegetables (, 56).

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

People use “keto” and “ketogenic” interchangeably—both refer to the same dietary approach.

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

Weight lost in the first week is mostly water. People report losing anywhere from about 1 lb (0.5 kg) to 10 lb (5 kg) or more anecdotally.

Learn more about first-week weight loss on keto.

Is keto good or bad for you?

The ketogenic diet can be beneficial for people who:

• are overweight
• have diabetes
• want to improve metabolic health

It might be less ideal for elite athletes or those aiming to gain significant muscle mass or bulk.

It may also not fit everyone’s lifestyle. Discuss your goals with your doctor to decide if keto is right for you.

The bottom line

On the ketogenic diet you markedly cut carbohydrates and replace them with healthy fats. This prompts your body to use fat for fuel, aiding weight loss and potentially lowering the risk of certain health issues.

That said, consult your physician before following the diet long-term, as side effects are possible. More research is needed to fully understand long-term effects on health.