What is the Keto Diet?

What is the Keto Diet?

Medically Reviewed by Dr. Bryan Seigel D.C., P.L.C.

The word “diet” is usually used to describe a short term change in the way we eat to achieve a desired outcome, most often weight loss. These kinds of diets aren’t sustainable in the long term, since they can involve dramatic calorie deficits, insufficient nutrients, miserable meals, and persistent hunger. The keto diet isn’t like that.

Is keto a crash diet?

It might be wiser to call keto a “WOE,” or Way Of Eating, since you can follow keto as a long term solution for optimal weight and health without feeling deprived, without dealing with cravings, having plenty of physical and mental energy, and eating foods you love. Doesn’t sound as catchy as the keto diet, does it? For simplicity’s sake, we’ll continue to call it a diet, albeit one you can happily follow for the rest of your life. Keto isn’t a crash diet, and while it will be effective for weight loss in the short term, if you return to the way of eating that put excess fat on your body, you can logically expect to put all that fat back on.

Many diets claim to give you success in 30 days, or 6 weeks, or 90 days. This is a very short timeframe to make a meaningful change in your body. You may see initial weight loss on traditional diets like this, but you’ll quickly reach a plateau, your energy and mood will suffer, and you’ll fall off the diet wagon. Most people regain more weight than they lost and wind up frustrated and less healthy, thinking something is wrong with them. No way, not at all! The problem is that these diets are marketed, and not based on the science of how your body works. If you’ve spent the majority of your life on a Western style or American style diet, you can make a meaningful step towards optimal health and ideal body weight within the first 3 months of a keto diet, but that short time is only the beginning of the positive changes you’ll be making for your long term success.

The Basics

What is the keto diet? A keto diet is a nutrient-dense whole foods diet that limits carbohydrate consumption to less than 20g per day. If you’re coming from a higher carb diet, and the vast majority of people are, it’s best to taper down your carbs over several weeks. The first week, aim for 80g of carbs a day, the second week, 60g, the third week, 40g, and in the fourth week, reduce to 20g of carbs per day, which is widely regarded as the sweet spot to ensure you get into, and stay in ketosis. Tapering off gives you a chance to gradually adapt to this way of eating, since abruptly cutting off carbs can lead to the dreaded keto flu, which feels like headaches and a lack of energy.

A well-formulated keto diet includes vegetables that are full of micronutrients, protein sources like muscle meats, eggs, and fish, and healthy fats like avocados, butter, coconut oil, and extra virgin olive oil. Did you read anything about counting calories, being deprived and feeling hungry, or using hard to find ingredients? No, no you did not. If your goal is weight loss, you may need to count calories after the first few weeks, but most people find that they naturally have less hunger because they’re consuming the nutrients that their body needs. You can add certain supplements to make keto better, and electrolytes are first on that list.

There are a number of variations of the keto diet. A cyclic keto diet involves planned higher carb days, an athlete can include more carbs and stay in ketosis because they burn through those carbs more efficiently, and lazy keto is full of prepared and packaged foods if you’re on the road or can’t prepare meals for any reason. The carnivore diet is a keto variation as well: simply eating meats keeps you in ketosis and you don’t have to think about counting carbs in other foods.

Some people pair the keto diet with intermittent fasting. This can range from choosing a set number of hours during the day to eat, and not eating anything the rest of the day, all the way to eating only one large meal per day. To get started though, it’s easiest to stick with your current eating schedule and simply switch to low carbohydrate foods. You can learn all about how to start the keto diet here. Let’s learn how it all works.

Put on your lab coat and goggles, science ahead!

Keto is short for Ketogenic, because ketones (small units of energy derived from fat) are generated as your body’s primary fuel source. These ketones are formed in your liver from the breakdown of fatty acids which can come from your foods or from your own fat stores, formally called adipose tissue, which is why on keto we eliminate carbohydrates from the diet. All carbohydrates, both sweets and starches, break down into glucose.

“But we need glucose in our blood or we’ll die!” Yup, you’re right! We will always (barring extreme illness) have about a teaspoon’s worth of glucose in our blood because there are cellular processes in the body, especially the brain, that require a little bit of glucose to work. Even if you eat zero carbohydrates, you will still have a little glucose in circulation because of gluconeogenesis. This is when the body creates glucose from other sources, usually protein, to meet your daily needs. This is a demand-driven process, meaning it will happen regardless of your protein intake at the necessary levels. If you eat too little protein, your body will unceremoniously rip protein from your muscles to make glucose. If you eat too much protein, your blood glucose may rise in response.

Eliminating the excess glucose in the blood translates to a decreased need for insulin, which is produced in the pancreas and is something like a key to the door in cell membranes. Insulin binds to glucose to shuffle it into cells for use as energy or to store it as a triglyceride molecule. Excess glucose in the bloodstream is highly inflammatory so your body is smart enough to get it out of circulation as fast as possible and safely stuffed into cells. Once stowed, it’s pretty tough to unlock the door to get it out, because insulin only wants to put things in like a hoarder.

When glucose is low, insulin is low, and ketones can be produced. This opens up the doors in cell membranes for two reasons: insulin isn’t preventing it, and ketones promote it. Easier opening doors means those triglycerides can escape to get burned as fuel for energy and you get a happy result: weight loss!

Keto isn’t just a short term diet to lose weight; it changes how your body runs. The keto diet has a long list of other benefits on top of easy weight loss.


The keto diet is a natural way of eating that has been with us since the earliest days of humanity when we were hunter-gatherers. It supports optimal health and helps to maintain ideal body weight in a sustainable way, and includes delicious foods you already love. There are several ways to approach a keto diet depending on your goals and lifestyle, but at the core, a keto diet is one where you include nutrient dense foods while excluding carbs.

Back to blog