Comprehensive Ketogenic Diet Guide

Comprehensive Ketogenic Diet Guide

The ketogenic diet has been around for a long time, but it's becoming more and more popular. But what is it? How does it work, and why should you consider it?

The ketogenic diet is a low-carbohydrate, high fat plan that has been used since the 1920s as an alternative treatment for epilepsy in children. Nowadays, it's not just for people with epilepsy anymore! In this article, we'll explore what the keto diet entails, how it works, and why it might be good for you.  

Interested in learning more about the ketogenic diet? Read on!

What is the ketogenic diet or ketosis?

The ketogenic diet is a low-carbohydrate, high-fat method of eating which shifts the body's metabolism away from glucose and towards ketone production. This metabolic state is called "ketosis". 

This might seem and sound complicated, but here's what happens with ketosis in simple terms: when we are not consuming carbs or sugars, our body switches to using fats (from the food that we eat and our own reserves) for energy instead.

As the body metabolizes fat,  ketones (compounds that result from fat breakdown) are produced. These ketones provide energy for the body and is an alternative source to glucose. 

The word ketosis comes from the word ketones, 'keto-' plus '-osis' which is a 'suffix expressing state or a condition, hereby denoting "a state of high levels of ketones in the blood.

The benefits of a ketogenic diet

A ketogenic diet has been found to have numerous benefits. Here are some of the more popular advantages:

Weight loss and its subsequent health benefits

The ketosis diet is a very effective way to lose weight, especially if you're someone who has been struggling with your weight for years.

It's important to note here that when we go on a caloric deficit (as in, not consuming enough calories for what our body needs), we also slow down our metabolism — which for most people is yet another reason why they can't shed the extra pounds. 

But during ketosis, our metabolism changes because the body burns fat instead of sugar from what we eat and our own stored supply, thus helping us to lose excess weight without putting the process of metabolism into overdrive.

Keto diet helps lower blood triglycerides

What are triglycerides and how can we benefit from low triglyceride levels in the blood?

Triglycerides are fat molecules that act as both fuel and fat stores in the human body. They can be found in the bloodstream too, just like cholesterol. Both triglycerides and cholesterol can be harmful to the cardiovascular system, increasing the risk of stroke and high blood pressure.

When one is on a keto diet, the body burns through the fat molecules in the bloodstream for energy. This means less triglycerides and cholesterol, and thus lower risks of stroke and heart disease.

Keto diet helps reduce blood sugar and insulin levels

As we all know, the body requires energy. The required amount of energy is provided by burning carbohydrates and fats. But when one is on a keto diet, the body will burn through its fat molecules instead of the carbohydrates for energy needs. In this case, there will be less glucose in the blood (as there are no carbs to turn into glucose).   

For someone suffering from type 2 diabetes (high blood sugar), lowering their daily carbohydrate intake can help keep their levels low and improve health. Ketogenic diets have been known to do just that - lower Hba1c levels in individuals with type 2 diabetes, which means better management of the disease.

It can help regulate appetite

Several studies show a reduction in perceived hunger with ketogenic diets.  This could be because ketone bodies suppress ghrelin, a hormone that increases appetite. It may also help manage weight for the long term. One study found sticking to a keto diet for one year helped participants lose more weight than those on low-fat diets.

A keto diet may improve mental performance and lower stress levels

One study on ketogenic supplements (an exogenous ketone supplement) found improved memory and reaction time after four weeks of ketone supplementation. The keto diet can also help lower stress levels, improve focus and decrease anxiety - these benefits could be key for the keto diet's ability to aid in mental performance.

Keto diets can also aid in lowering blood pressure

High blood pressure is one of the biggest risk factors for heart attacks and strokes. A keto diet can help lower it by 10-30%. Research shows that with a ketogenic diet,  people have a significant decrease in blood pressure.

Ketogenic diets can be therapeutic for several brain disorders

Before becoming popular in the weight loss industry, keto diets were used in patients with epilepsy. Although the association between the ketogenic diet and epileptic seizures is not well understood, there have been many cases reported where a keto diet substantially reduced the frequency and severity of seizure episodes in patients with epilepsy.

Researchers believe that it may be attributed to how keto diet process and metabolize ketones in the body. Study shows that ketones provide up to 50% of energy for the brain, which means ketogenic diets can act as a stand-in for glucose.

Other research has shown that the keto diet can also help manage several brain disorders including Parkinson's disease.

Foods to eat on a keto diet and foods to avoid

Now that we know some basics about the keto diet, the next question is: what keto foods are best?

Foods to eat on a keto diet

The ketogenic diet is a low carb, moderate protein, and high fat based nutrition plan.

Food choices on a keto diet should have the following macronutrient ratio: 5-10% carbohydrates, 30-35% protein and 55-60% fat by calorie (Masood et al., 2021).


Avocado is a keto-friendly food that is an excellent source of potassium, magnesium, and vitamins K & E, all nutrients which can help support ketosis.

slice avocado fruit

In addition to being keto-friendly, avocados also contain heart-healthy monounsaturated fat and fibre.


Dairy products like cheese are keto-friendly foods. It is relatively low in carbohydrates, which adheres to the basic principle of the keto diet.

sliced cheese on brown wooden chopping board

All types of cheese can be included on the keto diet, provided that the total carbohydrate intake daily remains at or below 20g.

Coconut milk

Coconut milk is one of keto diet beginners' favourite keto foods as it has a higher amount of fats than keto-friendly dairy products like butter/ghee. Moreover, coconut milk is rich in minerals like iron and potassium which plays important roles in the ketogenic diet. Coconut milk can be consumed by pouring into a keto smoothie or simply drinking it by itself.

Coconut Oil

Coconut oil is another perfect addition to a keto diet. It can be used as a keto-friendly cooking oil and can also be used in keto recipes.


If you are looking for keto-friendly food for a breakfast meal, you cannot go wrong with eggs. Eggs are an excellent source of protein and very low in carbohydrates.

dozen eggs on tray

However, they must be prepared properly for a maximum nutritional benefit; otherwise, they may not fit into ketosis requirements. For example, it should not be paired with potatoes like in an egg omelette since potatoes are high in carbohydrates.

Fish and shellfish

Seafood, including fish and shellfish, are good additions to a keto diet. They are full of essential nutrients that will help keto dieters during the ketogenic process. Generally, most keto-friendly seafood is lean in its fat content, which makes them healthy keto food options. Shellfish like lobster and crab is low in carbs and high in protein.

shallow focus photography of seafoods

Some fishes like tuna, catfish, salmon and cod are rich in omega 3 fatty acids which can also help reduce inflammation as well as lowering triglycerides levels in the blood.

Low-carb vegetables

Vegetables with less than five grams of net carbohydrates may be included in a keto diet.  Vegetables like green peppers, celery, carrots and spinach are keto-friendly and can be added to keto meals.

Meat and poultry

About 30-35% of the keto diet accounts for protein. This can be taken from meat and seafood. Poultry and fish are keto-friendly. Meat like pork, poultry, and beef are low in carbs but high in protein.

Meat products that come from ruminants contain heart-healthy fats which are keto-friendly unlike processed meats with preservatives. If you want to have pork or beef, make sure it comes from organic farms since this kind of meat doesn't contain harmful hormones.

Mushrooms (including portobello)

Mushrooms are nutritionally rich foods that can be included in many keto dishes. They also contain essential nutrients for ketosis such as selenium, potassium and others.

Nuts (walnuts and macadamias)

Nuts like walnuts, macadamia nuts, almonds, and the like, are keto-friendly sources of healthy fats!

brown wooden bowl with brown nuts

Nuts provide you with quick energy without having to eat carbs or protein. However, if you are planning to include nuts in your diet, it is recommended that you count your daily carb intake and stick with the keto diet plan.

Plain Greek yoghurt

If you are someone who loves yoghurt, you can still include it in your keto diet! Yoghurt contains lots of probiotics that can improve your gut health and ketosis.

It is also a good source of calcium, protein, potassium, phosphorus, magnesium and vitamins B12 and K2.

Keto Diet Foods to Avoid or Limit:

While keto diets are helpful for weight loss, it can be hard to know which keto food to avoid because there's no clear definition of what keto foods are good or bad. Some keto experts say that eating too many carbs will kick you out of ketosis while others say that ketosis is not about counting calories but still eat quality amounts of keto foods.

The food list below is more of general ketogenic diet foods to avoid and limit.


A ketogenic diet is typically low carb, which can lead to a fruitless lifestyle for some. One medium apple has more than 20 grams net carbsenough to blow someone’s allotment of carbs for the day. This especially rings true if you are someone who likes sweet snack fruit.

sliced apple

It’s unfortunate since we are all familiar to the saying "an apple a day keeps the doctor away", but in this case, here's what you should remember, apples aren't keto diet-friendly.


Barley is a no-no keto food because it's a high-glycemic, high-insulin and low-fat keto diet food. It is also one of the top ketosis inhibitors meaning that it can slow ketosis down by dramatically increasing insulin levels.

Barley contains gluten and has anti-nutritional properties which means you can end up overeating it especially if you're an active person or exercise regularly. The insoluble fibre in barley expands during digestion to make you feel fuller for longer but this only works until your body get used to it so barley becomes less effective over time as a ketogenic diet weight loss aid.


Corn contains lots of carbs, is a high-glycemic and low-fat keto diet food.

flat-lay photography of grilled corns

Diets based on it promote ketosis inhibitors and if you're active or exercise regularly then you need to limit the amount of corn in your ketogenic diet to prevent ketosis from slowing down or even coming to a halt.


Oatmeal is also high in dietary fibres. Oats break down into glucose rapidly and ketosis is slowed right down to a degree where it almost stops altogether if you're active or exercise regularly.


Quinoa is seen as a keto-friendly food because of its nutritional content but like corn, quinoa is very high in dietary fibre which means they break down into glucose too quickly for ketosis to be effective for weight loss purposes.

brown coffee beans in clear glass jar

You can eat this keto diet food occasionally but limit it if you want to see quick keto diet results.


Unfortunately, rye is a keto diet food to avoid. Rye breaks down into glucose very quickly in the body like barley, corn, oats, and quinoa. It can slow down ketosis right down to a degree where it almost comes to a halt especially if you are active or if you exercise regularly.


White rice is also a keto diet food that should be avoided because of its high glycemic index and glycemic load.

cooked rice

The same applies to brown rice, wild rice, red rice and black rice. It's best not to eat any at all if your goal is weight loss.

Soybeans and edamame

These foods contain a lot of carbohydrates, so keto dieters need to watch out for them.

Whole Wheat Flour

If you enjoy baking, be sure to avoid or limit this one. Whole wheat flour has the same amount of carbs as regular white flour—so you can’t use it for keto baking. 

Ketogenic recipes 

Looking for a cookbook to inspire your cooking on the ketogenic diet? Keto recipes need not be complicated or expensive. Here's a bundle of cookbooks which includes 3 sets of delicious, easy-to-prepare meals that are made with everyday ingredients such as leafy greens, avocados, and eggs.

These tasty recipes come from specialists in the field who show you how to create excellent low carb dishes by making smart substitutions for conventional high carb foods.

How to start a keto diet - what you should know before you begin

Okay, so we know what a keto diet is, how we can benefit from it, and the foods to eat and avoid. But, how does one start keto diet? It sounds like a complicated process but it's not all that difficult.

The most important step is to talk to your family doctor first and verbalize your interest in keto diet. You can ask him/her if you are fit to be in such diet and to suggest keto meal plans and ketogenic recipes based on your current weight, height, blood pressure, and other factors including your medical history and overall health condition. This way you are assured that keto diet is safe for you. With ketosis under control by your doctor, you can be ready to go!

Also, inform your family about your plan to be on a keto diet and weight loss goals. Like other forms of therapy, you need support so you can stick to your plan especially when you are tempted to give up keto diet. It is also advisable that you share keto diet information and ketogenic meal plans with your family, especially if they are interested to be on keto diet too. This way the whole family can work together in achieving ketosis success.

keto diet planning

Another thing that you need to do is planning ahead so you won't be caught off guard when hunger strikes or when a ketogenic recipe requires several ingredients to make one delicious keto meal. The key is learning how to read food labels and learning about the nutritional facts of foods and beverages that you consume daily.

If you feel uncomfortable and worried about the initial effects after starting keto diet, it is important to note all of them and share it with your family physician. Some individuals reported symptoms such as constipation, headaches, and mood swings, but these keto side effects do not last long. If your ketogenic diet is not working for you, then it's time to visit your doctor and ask him if there may be other keto diet plan that will work perfectly with your health condition.

If you are going keto because of weight loss, it's important to note that ketosis can help you burn fat fast in the early days but should be followed over a longer period so you won't gain all the weight back when your body adapts. Stay committed with keto and learn to use ketogenic recipes as a way of life instead of looking at them as another fad or short-term diet.

​​Home remedies for common side effects like constipation, headaches, or mood swings 

Side effects are common when changing dietary habits and lifestyles. The most common ones associated with keto diet include keto flu and constipation. But, the good news is that you can minimize these effects and eventually learn how to use ketogenic diet as a way of life.

Keto flu is the term given to keto side effects symptoms that occur during the first few weeks of ketosis adopting an ultra-low carb, higher fat diet. Keto flu is characterized by temporary feelings of fatigue, irritability, poor exercise performance, impaired learning and memory, mental fog or brain fog, tummy troubles (bloating), and muscle cramps or weakness.

Simple home remedies for such side effects can range from getting adequate rest periods, drinking a lot of water, taking keto supplements, to gradually eating ketogenic foods.

When to see a family doctor

If keto flu symptoms are too uncomfortable, or if symptoms persist for more than a few days to a week despite following your doctor or dietician's advise on how to start keto diet, then it's best to book an appointment and consult with your family doctor. The ketogenic diet is mostly safe as long as you stay within your carb limit. But keep in mind that following this diet can lead to serious complications, so it is not recommended for everyone.

Important Reminder

Weight loss results will vary from person to person. No individual result should be seen as a typical result of following the ketogenic diet.

keto diet

This website content is for informational purposes only and isn’t intended to replace or be a substitute for the guidance of your family physician. The statements on some pages have not yet been evaluated by the Food and Drug Administration.

If you have other questions regarding a medical condition or other matters related to this post, please book an appointment with your health provider. Never disregard or delay professional medical advice due to something you have read from any of the articles.

Applied Science Nutrition's customer service representatives are not qualified to answer any medical questions. If you think that you may be experiencing a medical emergency, call your primary physician, call 911 immediately, or go to the nearest emergency centre as soon as possible.


Masood W, Annamaraju P, Uppaluri KR. Ketogenic Diet. [Updated 2021 Jun 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: