Meal Matchmaker is a reader-supported site. Purchases made through links may earn a commission. Learn more.

What is Keto? Everything You Need to Know About the Ketogenic Diet

Last Updated on February 22, 2021

Everywhere you look today there’s a wide range of keto foods and keto-friendly options. And it sometimes feels like every single person you interact with is suddenly on keto and wants to rave about their new diet.

Keto has certainly taken both the health and fitness and the dieting world by storm. You would be forgiven for thinking it is a new craze but in fact, keto has been around since the 1920s when it was introduced by doctors in France as a treatment for epilepsy. It was widely used in this regard for decades until antiepileptic drugs gradually replaced ketogenic eating as the primary treatment option (1). 

Today, there is renewed interest in keto dieting, both within a healthcare context and among laypersons who want to lose weight and generally boost their health. If you’re considering making the switch to keto on the recommendations of your friends, you might be wondering what it is exactly and how it works.

Here, we go over everything you need to know about the ketogenic diet, including how it works, what you can eat, and the pros and cons.

What Does It Mean to Eat Keto?

When people say they’re eating keto, they are referring to a ketogenic diet that is characterized by high fat, adequate protein, and low carbohydrate intakes. The general idea is that keto fans get more of their energy needs from fats and protein than they do from carbs, particularly simple carbs like those found in refined sugar and most breads.

When you eat like this, your body switches its metabolic processes around and the effects can be striking. As the authors at Harvard Health Publishing put it “The keto diet aims to force your body into using a different type of fuel. Instead of relying on sugar (glucose) that comes from carbs (such as grains, legumes, vegetables, and fruits), the keto diet relies on ketone bodies, a type of fuel that the liver produces from stored fat” (2).

In order to burn stored fats though, an individual’s liver must produce ketones, which is quite a tall order. Dieters must restrict their net carbohydrate intake to around 20 to 50 grams per day to reach a state of ketosis. Additionally, it can take several days to achieve ketosis.

Eating keto is a means of essentially biohacking one's own metabolism and forcing changes. While it is highly effective for weight loss, the keto diet is also well suited to address a range of health issues, such as type 2 diabetes, which we'll discuss more later on in the article.

So to summarize, eating keto means following a high-fat, adequate-protein, and low-carb diet that enforces metabolic changes in the body. Dieters follow keto plans to lose weight and sometimes to address underlying health issues.

What Can You Eat on a Keto Diet?

Keto enthusiasts could rave about the positive benefits of this lifestyle for hours and you’d be hard-pressed to not hear them mention points that include weight loss, mental clarity, increased energy, and reduced appetite; in addition to overall health benefits like treating and sometimes even reversing diabetes, lessening the risk of heart disease, improving the symptoms of PCOS, and lowering blood pressure. 

These same enthusiasts tend to shy away from bragging on the types of foods they’re eating on a daily basis as there’s so much misconception about how the keto diet actually works. Of course, naysayers will insist that both simple and complex carbohydrates need to be included in a “balanced” diet. They’ll also remind you of all the foods a ketoer can’t have — “how could anyone live without pasta?” Plus, “all that fat can’t possibly be good for your arteries.”

Don’t listen to them. Instead, focus on the absolute bounty of delicious and nutritious foods you can enjoy. If you want to make things easy on yourself, take a look at our list of popular keto meal services.

Imbibe With Impunity

Bacon and full-fat cheese come to mind as favorites, as such foods would typically fall into the “avoid” category of many other diets, especially those of the low-fat variety. Indulging in rich foods on keto helps to counter the deprivation problem. 

Keto also allows you to get really creative with your vegetables as well. Always remember that there are no vitamins and minerals in fruit that you can’t get from a variety of vegetables. A good rule of thumb here is that if it grows above the ground, it’s generally keto-approved. Veggies that grow beneath the earth’s surface are often much starchier, packing way higher carb contents. 

Come to appreciate leafy greens and don’t discriminate, you’d be surprised at how delicious kale can be when seasoned well and prepared properly. 

Cauliflower is one of the most diverse vegetables that can be incorporated into the keto diet. It can be eaten raw, roasted, steamed, or magically turned into substitutes for some of those carbs you so desperately might miss from your pre-keto days like rice and mashed potatoes (you’re not likely to miss those things as much as you’d think after just a couple of weeks). As if that weren’t enough, cauliflower can even be turned into a pizza crust.

When you’re eating keto, the healthy fats you consume are what keep you fuller for longer. Don’t confuse these for those trans fats often found in highly refined and processed foods. 

Avocado is a superfood that’s jam-packed with loads of fiber and healthy fats along with a laundry list of micronutrients that contribute to a well-rounded diet. Throw an avocado on your salad, make some guacamole, or get ambitious and bake some eggs in the halves. 

More healthy fats can be incorporated in food prep. Olive oil, butter, greek yogurt (full-fat only!), and coconut oil are all great pantry and fridge staples. Just make sure you leave enough room for all the wonderful and varied cheeses you’re going to be able to enjoy without any of the guilt. 

Let’s not forget seeds, nuts, and nut butters as well. These can be enjoyed in moderation on a healthy and well-balanced keto diet. Other excellent sources of healthy fats that are also packed with much protein include fish like salmon and tuna which include so much protein as well as omega-3s, whole eggs, which are incredibly versatile and always affordable.

So as you can see, there's plenty you can eat on keto. If you're struggling with your diet, try and focus on all the delicious stuff you can imbibe with impunity as opposed to all the carbs you're cutting. 

All that high protein and high fats will keep you feeling full, so there's a good chance you won't feel any FOMO anyway. Many keto dieters also take comfort in the fact that they're eating whole foods, instead of over-processed stuff full of nasties.

The Keto Food Pyramid

As children, we learned about food pyramids in school. These triangular diagrams help people visualize what they should eat more of and what they should eat less of. 

But the traditional food pyramids we were shown as kids are carb-heavy and full of fast-release starches. The keto food pyramid, on the other hand, displays the ketogenic diet’s main food groups and doesn’t privilege carbohydrates as traditional food pyramids do.

If you’re new to keto or still finding your feet in this diet, having a copy of the keto pyramid somewhere in the kitchen can serve as a helpful reminder of what to eat (and what not to eat too!).

Here are the tiers in the keto pyramid. You should get the majority of your daily calorie needs from the top tiers and less of your calories from the bottom tiers.

  • Healthy oils and fats
  • Lean protein, fish, and eggs
  • Non-starchy vegetables
  • Low-carb vegetables
  • Full-fat dairy products
  • Berries and nuts

Remember, keto is more about healthy fats than high protein and in fact, too much protein can knock you out of ketosis. In this respect, it is vastly different from other traditional diets that recommend more carbs and low-fat eating.

Balancing Your Macros

Macros, or macronutrients if we’re being scientific about it, describe the nutrients we intake and that provide us with energy. You can think of macro as meaning big and micro as small when it comes to nutrients, so we need fewer micronutrients and more macronutrients.

As one Heart Foundation dietician puts it, macros are “the nutrients we need in larger quantities that provide us with energy: in other words, fat, protein and carbohydrate. Micronutrients are mostly vitamins and minerals, and are equally important but consumed in very small amounts” (3).

On your keto journey, you will probably hear an awful lot about macros, whether it’s chatting to your friends in person or getting keto support from online forums. And it often seems like everyone has their own idea of the perfect macro balance, that is, what percentage of each macro group should make up your daily diet.

But the truth is that there is no perfect universal macro balance. Rather, the best macro balance for you is the one that suits your body best. That might not be very helpful when you first start out, so you can stick to the basic rule of thumb which is:

  • 5 percent of your calories from carbs
  • 25 percent from lean protein
  • 70 percent from healthy fats

With this macro plan, your body should go into ketosis and burn fat for energy instead of carbs. As we said above though, many keto dieters like to tweak this plan slightly. If you do tweak, just remember the keto golden rules:

  • High fat
  • Moderate protein
  • Very low carb

Using a food diary, such as the popular one in the MyFitnessPal app, is a great way to keep track of your macros. You can set it to the above percentages to ensure you’re staying on track. 

Additionally, some ketogenic diet followers like to set their macro balance according to their own body. If this sounds like you, try one of the many free keto macro calculators available as these offer dieters a personalized breakdown. 

Is Keto Diet Good for You?

Low-carb diets have gained and lost popularity on a regular basis long before the days of the popular Atkins diet. The rise of the keto diet is nothing short of astronomical, and it has sparked an ongoing debate between experts who are undecided on both its value and it's health benefits. 

While proponents tout a wide range of benefits, including reversing or minimizing the effects and severity of type 2 diabetes (more on that below), scientific studies are a bit slower to catch up. That's not to say there are no studies, quite the opposite, a large body of research is dedicated to the ketogenic diet. But as the New York Times noted in 2019, many of these studies are small and of a shorter duration.

Still, there are plenty of medical professionals who endorse the keto diet and actively prescribe a low-carb diet to their patients who are struggling with type 2 diabetes, obesity, and even heart disease. One example is Dr Ethan Weiss, a preventative cardiologist at the University of California.  After switching to a ketogenic diet himself, Weiss noted that he felt better than he had in years and went on to set up a company that sells a ketone measuring device. 

Other practitioners worry about the effects of high fat consumption and its link to heart disease, particularly if the dieter in question is not educated about the differences between good fats, such as olive oil and avocado, and saturated fats. Further questions have been raised regarding a ketogenic diet and its effects on the pancreas liver, thyroid, and the gallbladder.  With respect to these, dieticians from the University of Chicago warn that the ketogenic diet is not suitable for those who have issues with any of these organs (4).

One thing is for sure though, the keto diet is not a fad, despite the fact it may seem like that at times. It is widely accepted that a low-carb diet, or restricting carbs at meals leads to stable blood sugar levels after eating. The result of this is lowered insulin levels, a hormone that causes weight gain. And for many, this is the prime reason to make a switch to a ketogenic diet: it is highly effective as a weight loss plan.

A ketogenic diet was frequently prescribed to diabetics prior to the discovery of insulin in the early 1920s. And until modern medicine adjusted its way of treating type 2 diabetes in line with new discoveries, the health benefits of the keto diet for diabetics were undeniably accepted.

Perhaps it is best to say that the keto diet may be good for you and your body, depending on your own unique physiology. Everyone is unique after all, and what's good for one person may not necessarily suit another. If you're unsure if a ketogenic diet is right for you, take some time to discuss it with your GP. They may decide that the potential health benefits outweigh the side effects and endorse your choice to go keto.

Research into the ketogenic diet and metabolism, blood sugar levels, cholesterol levels, weight loss, and many other bodily factors is still ongoing, it will certainly be interesting to see what the scientific community comes up with and whether they will reach a consensus. In the meantime, watch this space.

Ketogenic Eating and Health Issues

We covered some of the health complications that are linked to the ketogenic diet above, but for ease, here we quickly look at the main interrelated keto diet and health factors.

Type 2 Diabetes: It is widely known that a ketogenic diet can help control diabetes by altering the production of insulin.

Heart Disease: There is some evidence that a ketogenic diet lowers cardiovascular risk factors, like obesity. Other studies note report spikes in “bad” cholesterol, hypoglycemia, and heart problems. 

Cholesterol Levels: A keto diet is linked to a lowered level of LDL cholesterol, triglycerides,  and blood glucose levels. However, there is also evidence that a keto diet can increase the level of HDL cholesterol.

Blood Sugar: A ketogenic diet can improve blood sugar levels and lower the need for insulin.

Polycystic Ovary Syndrome (PCOS): There is some evidence that a keto diet can relieve the symptoms of women with PCOS. Studies note that the effects are greater in women who are obese or overweight. However, plenty of anecdotal evidence abounds with women of all weights noting that keto helps with PCOS.

The Good, the Bad, and the Side Effects

Much like with any dramatic change to your eating habits, there are some side effects to be aware of on your ketones diet. Most commonly, keto followers complain about the “flu” and the bad breath associated with strict keto plans. 

Let’s take a look at each of those now before covering the other possible, but less common, side effects.

What Is the Keto Flu?

One of the drawbacks of beginning a ketosis diet is the dreaded keto flu. Although it is not a true flu, per se, the signs and symptoms mimic those of a flu. The keto flu generally begins within the first week of starting the diet and it is a short term issue that normally resolves quickly.

You may feel nauseous, dizzy, or unusually tired. Or you may have no flu symptoms at all. Researchers of one study that tracked anecdotal evidence of the keto flu across online forums note that it is unclear why the diet has this effect. But the authors do go on to say that it may be because of changes in the gut microbes (4).

Why Do I Have Bad Breath on Keto?

Keto breathe is rather distinctive and should not be thought of as the same as halitosis or other issues that cause bad breath. With keto, you have raised levels of ketones in your body, these ketones exit your body via the breath and urine. 

There’s no doubt about it, keto breath can be pretty nasty. And it common enough that comic Hannah Gadsby takes a pointed stab at it in her Netflix special. Thankfully though, the keto breath should subside after a couple of weeks. And if it helps, remind yourself that the fruity breath you now possess is an indication that your body is in ketosis and burning fat for energy.

Other Keto Side Effects

Besides the flu and the fruity, acetone-tinged breath, you might find yourself contending with the following issues:

  • Excessive thirst
  • Lowered libido
  • Dehydration
  • Constipation
  • Difficulty sleeping

It goes without saying, but if you're experiencing side effects and you're unsure of whether you should continue your keto diet, please get in touch with a medical professional to make sure your health is okay. 

Do not ignore any side effects that are significantly impacting your day to day life. Also, remember to drink enough water each day to support your digestion and help avoid issues with constipation the keto diet may bring about.

A Ketogenic Diet and Weight Loss

Now that we've looked at negative stuff in more depth, we can turn our attention to the positives, and more specifically, losing weight on keto. The weight-loss advantages of a low-carb, high-fat diet are well described and undeniable. Most people on the ketogenic diet lose an average of 1 kilogram/2.2 pounds per week, particularly when they stick to less than 50 grams of carbs per day.

Overall, long term dieters on the ketogenic diet report massive weight loss, and many have gone from obese to trim within a year. It doesn't take long to find these success stories, in fact, the internet abounds with individuals crediting a low carb diet to their long term weight loss. There are plenty of celebrities in the mix too, for example, Jenna Jameson, who lost 85 pounds with long term keto.

According to the BBC, "Research has shown a ketogenic diet can induce rapid weight loss, partly from water loss but also some fat loss" (6). So you should expect much of the early weight loss to be water weight as opposed to a huge fat loss.

Additionally, your weight loss may peak in the short term but then slow down once you've been on the diet long term.  When that happens, many keto diet aficionados choose to combine their keto diet with intermittent fasting.  Doing so prompts the weight loss process to begin in earnest again. The trick with intermittent fasting (IF) is to ensure you get enough calories per day, too little and your body will go into something akin to a starvation mode and stop burning fat.

People who combine a keto diet with IF opt for one of several eating plans: the 5:2 diet where dieters eat normally on two days but restrict calories to just 500 on two days or the week; or the 16:8 where dieters eat only in an eight-hour "feeding window." With the latter option, you can also adjust the window to make it shorter or longer, depending on your daily schedule.

Whether you decide to go down the IF route when you hit a ketogenic diet plateau or not is up to you. Other dieters find it just as effective to stick to the high fat keto diet alone and wait out the leveling of their weight loss.

Final Thoughts

Keto is a great way to lose extra weight, gain more energy, and help with a range of health issues. But it might not suit everyone, so remember to ask your GP before you begin. 

Already eating keto and getting bored of olive oil fat bombs for brunch? Check out the awesome range of keto-friendly ready meals on offer here. Best of luck on your keto journey and enjoy the ride!


1. Wheless, J., 2008. History of the ketogenic diet. Epilepsia, 49, pp.3-5.
2. Publishing, H., 2020. Should You Try The Keto Diet? - Harvard Health. [online] Harvard Health. Available at: <> [Accessed 3 August 2020].
3. 2020. What Are Macronutrients?. [online] Available at: <> [Accessed 4 August 2020].
4. 2020. Ketogenic Diet: What Are The Risks? - Uchicago Medicine. [online] Available at: <> [Accessed 5 August 2020].
5. Bostock, E., Kirkby, K., Taylor, B. and Hawrelak, J., 2020. Consumer Reports of “Keto Flu” Associated With the Ketogenic Diet. Frontiers in Nutrition, 7.
6. BBC Food. 2020. Is A Keto Diet The Best Way To Lose Weight?. [online] Available at: <> [Accessed 5 August 2020].


Join the discussion here on Facebook.

Hi, I'm Paul. Welcome to my website! I, along with my cronies, are leveraging our years of working in the food industry to review meal and drink delivery services. We review. You eat happily ever after.

Read These Next

Exploring the Nordic Diet: What Is It and What Can You Eat?

Exploring the Nordic Diet: What Is It and What Can You Eat?

Benefits of a Vegetarian Diet

Benefits of a Vegetarian Diet

Types of Meat and Their Benefits: A Tasty Guide

Types of Meat and Their Benefits: A Tasty Guide

How To Transition To A Carnivore Diet

How To Transition To A Carnivore Diet

Top Choices: Best Carnivore Diet Supplements

Top Choices: Best Carnivore Diet Supplements

What Is The Sirtfood Diet?

What Is The Sirtfood Diet?
{"email":"Email address invalid","url":"Website address invalid","required":"Required field missing"}