Keto Diet 101: What is a Ketogenic Diet?
If you want to know what a ketogenic diet is, and what are some good keto diet foods to eat, then you want to read this article.
Over the past few years, keto has exploded in popularity as people continue to search for “the key” to successful, sustainable weight loss.
If you’ve heard of keto or know someone following a keto diet, you’re probably wondering, “What is a ketogenic diet, and can it work for me?”
In this guide, we’ll answer all the questions and more, but first, let’s start with the basics...
What is Keto?
Simply put, the ketogenic diet is a very low-carb, moderate protein, high-fat diet that shares some similarities with other popular low-carb diets, such as the Atkins Diet.
In terms of macronutrient breakdown, the ketogenic diet contains:
As you can see, keto is basically the polar opposite of the low-fat, high-carb days of the 1990s where everyone was binging on fat-free cookies, cakes, and candy while at the same time getting a heaping helping of refined sugars.
What is the Purpose of Following a Ketogenic Diet?
One of the biggest selling points you’ll hear about the ketogenic diet is that it makes your body “burn fat for fuel.”
And, it’s true that when you follow a ketogenic diet, you will enter into a state of ketosis, whereby your body is deprived of glucose (its primary and preferred fuel) and must resort to running on ketone bodies.
Ketone bodies (ketones) are energy-yielding molecules generated in the liver from the breakdown (oxidation) of fatty acids. There are three different types of ketones, in:
- Beta-hydroxybutyric acid (BHB)
- Acetoacetate (AcAc), and
As we mentioned the body generates these ketones when it is deprived of glucose and glycogen (the storage form of glucose) levels are low.
Ketone production occurs whenever a person fasts for a prolonged amount of time or following a bout of intense, long-lasting exercise. They can also enter ketosis when they adopt a low/no carb diet, such as the ketogenic diet.
As the body breaks down and oxidizes (“burns”) body fat for energy, ketones are produced, which serve as the default fuel for your muscles and brain in the absence of glucose.
Seems pretty straightforward, right?
Well, where things start to get a bit squirrely is when keto advocates start interchanging the terms “burn fat for fuel” and “fat loss.”
The two are very different.
You see, just because your body is burning fat does not mean it is losing fat.
In order to lose body fat, you have to be in a calorie deficit.
What this means is that even if you consume all of your calories from fat and protein, nary a carbohydrate in sight, and are eating more calories than your body needs in a day, then you will gain weight.
This is because body weight ultimately boils down to thermodynamics, i.e. calories in vs calories out. And, this is also why you can still lose weight while eating carbohydrates.
Now, the reason that many people enjoy following a ketogenic diet is because some people find they enjoy higher levels of satiety eating more fat and protein than carbohydrates.
However, other people feel less hungry (and perform better physically) when they eat more carbohydrates and a lower amount of dietary fat.
This is why a number of studies have shown that ketogenic and low-carb diets are no more effective for long-term weight loss than higher-carb diets.[3,4,5]
The takeaway here is that the ketogenic diet can be used for weight loss, but it is not the only diet you have to follow to lose body fat. And it is not superior to higher-carb diets in terms of fat loss or body recomposition when protein and calories are equated.
So, how did the ketogenic diet come to be?
Origins of the Ketogenic diet
The origins of the ketogenic diet are quite different from other low-carb diets, in that the ketogenic diet wasn’t founded out of an abject (absurd) fear of carbohydrates, but created to treat a medical condition.
The first notable occurrence of the road to the creation of the ketogenic diet occurs in ancient Greece where the “Father of Medicine” Hippocrates came across a patient who had been suffering from seizures for five straight days.
On the sixth day, Hippocrates suggested that the man abstain from all food and drink, and what do you know?
The man had no seizures!
The next notable moment in the history of the ketogenic diet comes in 1000 AD, with Avicenna, a Persian physician who coined the term “epilepsy” which is derived from the Greek word epilambanein -- to seize or attack).
Our next stop along the ketogenic history timeline comes some 900 years later in France where doctors begin implementing bouts of fasting to treat the seizure episodes in epileptic children.
Around this same time, an American named Bernarr McFadden was championing the concept of prolonged periods of fasting (three days to three weeks) as a cure for anything and everything.
However, there comes a point in time when the body requires nutrition to sustain life, and as such, as great as fasting is for combating certain diseases, it’s not something that can be carried out ad infinitum.
At a certain point, the body will enact a cavalcade of chemical signals to make us crave food and seek it out.
Left with the quandary between sustaining life, yet maintaining a quasi-fasted state, researchers began tinkering as they do and developed a “fasting-mimicking” diet of sorts that gave the body enough nutrients to survive yet didn’t lead to the onset of seizures.
Thus, in the early 1920s, the “ketogenic diet” diet was born.
As you can see, the ketogenic diet wasn’t created out of some ridiculous fear that carbohydrates or insulin make us fat. It was created to treat epileptic seizures in children.
But, that hasn’t stopped the fad diet world from “borrowing” (stealing) it and trying to make it sound like the second coming.
And, over the past several decades we’ve seen ultra low-carb, high fat diets pop up from time to time.
What Does a Ketogenic Diet Look Like?
“Ultra low-carb” sounds a bit too vague, so to help you wrap your head around what it means to eat a ketogenic diet, let’s set forth some rough estimates.
Generally speaking, ketogenic diets contain less than 50 grams of net carbs per day.
These carbs typically come from green, non-starchy vegetables, such as spinach, kale, or broccoli.
It’s worth mentioning, that if this is your first time trying keto, you’d be best served to eliminate carbs altogether (maybe 10-15 grams per day) as this will accelerate your transition to nutritional ketosis.
To give you an idea of what 10-15 grams of carbohydrates looks like in terms of your current nutrition plan, it’s equivalent to approximately one-1 oz piece of bread, ⅔ cups unsweetened fat-free yogurt, or 4 ounces of fruit.
As you can see, that doesn’t leave a lot of wiggle room for starchy carbs in the diet.
The only carbs you will eat on a keto diet are green veggies (asparagus, spinach, kale) and other non-starchy vegetables, such as mushrooms, peppers, and celery.
You must also be cognizant of your protein intake while following a ketogenic diet as consuming too much protein can kick you out of ketosis or prevent you from entering into it.
This is due to the fact that consuming too much protein at one time can induce gluconeogenesis, a biological process where your body generates glucose from non-carbohydrate precursors (such as protein).
5 Types of Ketogenic Diets
Standard Ketogenic Diet
The standard ketogenic diet is what most people are referring to when they say they’re going “keto.”
It is a very high fat, moderate protein diet that restricts carbohydrate intake to generally no more than 50 grams of net carbs per day.
This style of ketogenic diet is the one that is the most heavily researched, as well as the one with the most research-backed benefits.
Targeted Ketogenic Diet
Targeted ketogenic diets are used by athletes who like to take advantage of the performance-boosting power of carbohydrates for their training sessions but follow a strict ketogenic diet all other times of the day.
Individuals following targeted keto diets consume 30-50 grams of net carbohydrates ~30-60 minutes prior to training.
Cyclical Ketogenic Diet
Cyclical ketogenic diets involve rotating between periods of eating keto with periods of consuming higher amounts of carbohydrates. One of the most commonly used cyclical ketogenic diets has an individual eat very low carb for 5-6 consecutive days followed by 1-2 days of higher carb intake.
The higher carb days serve to help replenish glycogen levels in the body, which can pay dividends to recovery and performance in training.
High-Protein Ketogenic Diet
This spin on the traditional (standard) ketogenic diet bumps up the protein from 20% to roughly 30-35%, while still keeping carbs in the 5-10% of daily calories.
Plant-based (Vegan) Keto Diet
Plant-based (vegan) keto is essentially a standard ketogenic diet with the caveat that you consume only plants, no animal-based products.
While possible, these diet is even more tedious and restrictive than the standard ketogenic diet, and as such individuals may struggle to adhere to it for prolonged periods of time.
Approved Keto Diet Foods
The fattier the cut the better!
- Ham (no sugar added)
Eggs & Dairy
- Whole eggs
- Heavy cream
- Full-fat cheese
Nuts & Seeds
Nuts and seeds contain plenty of healthy fats and protein, but due to their carb content, they must be eaten in moderation.
- Macadamia nuts
- Pumpkin seeds
- Chia seeds
- Flax seeds
Low-carb, non-starchy veggies are you go-tos here. Some examples include:
- Brussels Sprouts
- Lettuce (such as romaine and arugula)
- Bok choy
- Green beans
- Extra virgin olive oil
- Coconut oil
- Avocado oil
- MCT oil
- Avocado oil
- Macadamia nut oil
Fruit (with the exception of olives and avocados) is almost pure carbohydrates, which means you need to try to limit your fruit intake to one serving per day to keep your carb total in check.
Here are our top keto fruit choices:
- Black coffee
- Unsweetened tea
- Avoid sugary condiments and spice blends (ketchup, etc.)
Foods to Avoid on Keto
- Red beans
- Black beans
- Pinto beans
- Chickpeas (garbanzo beans)
- Russet potatoes
- Sweet potatoes
- Sports drinks
- Fruit juice
- Basically anything that comes in a box, bag, or wrapping
The ketogenic diet is a high fat, moderate protein, very low carb diet whose purpose is to force the body into a state of ketosis where it primarily relies on ketone bodies for energy rather than blood glucose and glycogen.
The ketogenic diet can help you lose weight, as can many other type of diets, including ones that allow you to eat carbohydrates.
Is the keto diet better than a more balanced nutritional approach for weight loss?
Remember, a calorie deficit is ultimately what dictates fat loss or not. If by following a ketogenic diet you are able to maintain your calorie deficit consistently, then it can work. However, it is entirely possible to lose weight (and millions of people have done so successfully) without eliminating an entire macronutrient.
- Wheless, J. W. (2008). History of the ketogenic diet. Epilepsia, 49 Suppl 8, 3–5. https://doi.org/10.1111/j.1528-1167.2008.01821.x
- Fromentin, C., Tomé, D., Nau, F., Flet, L., Luengo, C., Azzout-Marniche, D., Gaudichon, C. (2013). Dietary Proteins Contribute Little to Glucose Production, Even Under Optimal Gluconeogenic Conditions in Healthy Humans. Diabetes, 62(5), 1435 LP-1442. https://doi.org/10.2337/db12-1208
- Naude CE, Schoonees A, Senekal M, Young T, Garner P, Volmink J. Low carbohydrate versus isoenergetic balanced diets for reducing weight and cardiovascular risk: a systematic review and meta-analysis [published correction appears in PLoS One. 2018 Jul 2;13(7):e0200284]. PLoS One. 2014;9(7):e100652. Published 2014 Jul 9. doi:10.1371/journal.pone.0100652
- Phillips SA, Jurva JW, Syed AQ, et al. Benefit of low-fat over low-carbohydrate diet on endothelial health in obesity. Hypertension. 2008;51(2):376–382. doi:10.1161/HYPERTENSIONAHA.107.101824
- Thomson, C. A., Stopeck, A. T., Bea, J. W., Cussler, E., Nardi, E., Frey, G., & Thompson, P. A. (2010). Changes in body weight and metabolic indexes in overweight breast cancer survivors enrolled in a randomized trial of low-fat vs. reduced carbohydrate diets. Nutrition and Cancer, 62(8), 1142–1152. https://doi.org/10.1080/01635581.2010.513803
- Johnston, C. S., Tjonn, S. L., Swan, P. D., White, A., Hutchins, H., & Sears, B. (2006). Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets. The American Journal of Clinical Nutrition , 83(5), 1055–1061. Retrieved from http://ajcn.nutrition.org/content/83/5/1055.abstract