What is the Keto Diet?

The ketogenic diet (or keto diet for short) is an exceptionally well-researched and proven method to start working with your body, rather than against it, to improve your health. Following the basic rules of the keto lifestyle can help you

• Feel more energized.
• Lose weight faster.
• Improve the health of your heart.
• Sharpen your mental focus.

In addition to these benefits, there are a host of other long-term benefits that will leave you jumping for joy. Though it’s become popular recently, the keto diet has been used for almost a hundred years to heal and prevent disease — that’s a long track record of benefits.

In a nutshell, the keto diet is

• High fat
• Moderate protein
• Very low carbohydrate

Having grains and carbohydrates form the basis of every meal may seem like contemporary wisdom, but for most of human history, this wasn’t the case. Processed and easily digested carbohydrates fuel weight gain and unhealthy spikes in blood sugar with each bite; over the course of a lifetime, this destroys your health.

The keto diet puts your body into ketosis, a process where you use fats, rather than sugars from carbohydrates, to fuel your body. On the keto diet, you’ll learn to turn to nutritional powerhouses — fats — into the basis of your meals.

The truth is that fat really isn’t to blame for the increasingly common problems of obesity and being overweight that we always hear about. Fat is actually very good for you, keeps you feeling fuller longer, helps you lose weight, and improves your health over the long term.

There are a lot of misconceptions about nutrition in general, and the keto diet in particular. The keto lifestyle is much more than the “bacon wrapped in cheese” memes will have you believe — although you can eat cheese and bacon. It won’t wreak havoc on your heart or blood vessels, nor will it increase your cholesterol levels if you follow a whole-food-based keto lifestyle.

Despite what many of us have been told for decades, we don’t need to eat many carbohydrates as part of a healthy lifestyle. Instead, eating a range of whole keto foods can be the key to healthy living. Keto is a flexible and adventurous lifestyle that isn’t a one-size-fits-all plan; there are several different varieties to fit with your lifestyle and goals.

Standard ketogenic diet

The standard ketogenic diet is the basic version of the keto diet. It’s been around the longest and has the most evidence and research behind it. If you’re thinking about keto, you need to be very familiar with the standard ketogenic diet. It clearly breaks down the sources of your daily calorie intake, as follows:

• Fat: 70 percent
• Protein: 25 percent
• Carbohydrates: 5 percent

Historically, on this diet, you’ll generally eat about 25 grams of carbohydrates per day. However, we live in more flexible times, and some people eat as much as 50 grams per day. That’s okay, because most people stay in ketosis on 50 grams of carbs a day, so they don’t need to limit their carbs anymore. Over time, you’ll figure out what works best for you.

The amount of daily carbs is, at most, only a fifth of what many Americans eat. On the standard American diet, you get about 30 percent of calories from fat, 20 percent from protein, and 50 percent (or more) from carbohydrates. That means most Americans are eating about 250 grams of carbs or more per day. As you can imagine, making such a radical change from a carb-based diet to a fat-based one will have a massive impact on your health and energy levels.

On the standard ketogenic diet, the ratio is 70:25:5 in terms of calories coming from fat, protein, and carbs. You should aim for 30 grams of carbs or fewer in a day.

Targeted ketogenic diet

The targeted ketogenic diet is geared toward athletes. It’s a slightly more flexible version of the keto diet because it allows you to eat more carbs around the time of your intense workouts. When you’re burning a lot of calories, the carbs you eat are consumed as fuel immediately, so your body doesn’t get “kicked out” of ketosis in the long term. As soon as you use up all the carbs during your workout, your body goes back to fat burning because there aren’t carbs left around when you’re more sedentary.

This choice is good for very active people who are exercising at high levels regularly (for hours, not minutes) or training for an intense athletic challenge that requires a lot of energy, like a marathon. Regardless, this is not a free pass to eat as many carbohydrates as you would on a high-carb diet. You should consume about 20 or 25 grams of easily digestible carbs approximately 30 to 45 minutes before you exercise. After exercising, you’ll go back to the regular keto diet. Keep in mind the total number of calories (including your pre-workout carbs) when coming up with your daily energy intake.

It’s critical that you only eat enough carbs to fuel your workout, so your body goes back to burning fats when you’re done exercising. Generally, you should be well adjusted to the standard ketogenic diet for a couple months at least before you switch to this targeted version.

Cyclical ketogenic diet

The cyclical ketogenic diet is another more flexible keto option for highly trained athletes. We’re upping the playing field here — this is the ultramarathon runner or the professional athlete, not the weekend warrior. These athletes may increase their carb intake for a short time to “fuel” themselves for the high level of performance they’re about to commit to. The increase may be for a couple of days before a major training event — and the amount of carbs they consume is in line with the amount of physical activity they’re facing. Then they go back to the standard ketogenic diet after the major event is over. Although they may be out of ketosis during these “cheat days,” their high level of performance ensures that they’re still in the low-carb range because they’re burning so many more calories than usual.

Another group of people who follow the cyclical ketogenic diet are those who have a hard time sticking to the standard ketogenic diet and choose to have cheat days once in a while. This may involve going keto five days a week, with the weekends reserved for “cheat days.” For those who eat carbs on the weekend, or can’t stick to the standard ketogenic diet because of social pressures, it’s important not to go on carb-binging cycles. It’s quite a shift for the body to go from ketosis to high-carb so rapidly. Instead, increase your carbs to a “low-carb diet,” in the range of 150 to 200 grams on your cheat days. You won’t be in ketosis on those days — and it may take a while for your body to go back to ketosis even on your regular standard ketogenic diet days — but at least you’ll still have the benefits of cutting back on carbs.

The cyclical ketogenic diet may be helpful for athletes and those who find it difficult to commit to the keto lifestyle. Keto is very flexible and can work with any lifestyle, as long as you make a commitment to health.

High-protein ketogenic diet

In the high-protein ketogenic diet, you increase the percent of calories from protein. Commonly, this breaks down as follows:

• Fat: 60 percent
• Protein: 35 percent
• Carbohydrate: 5 percent

This option is best for people who are concerned about losing muscle or even want to bulk up, like bodybuilders or individuals who have very low lean body muscle mass. Generally, keto is a muscle neutral diet (you don’t gain or lose it), so adding protein is a great choice for those who want to gain muscle. In this diet, you’re still in ketosis, but you don’t necessarily have as high a level of ketones as someone on the standard ketogenic diet. It’s hard, but possible, to get kicked out of ketosis if you go higher than the recommended 35 percent of calories from protein. It’s also important on this type of keto diet to remember to eat a range of protein foods that are healthy and nutritious.

Burning fat: Ketosis

Ketosis is the process your body uses to breaks down ketone bodies for most of its energy needs. Ketones come from fatty acids regardless of whether you eat them or get them from your fat cells. Your body prefers to use glucose for energy (see the preceding section), so ketosis only occurs when you don’t have enough glucose coming in from your diet. On a keto diet, your body switches from glycolysis to ketosis as the primary energy generator.

Fat, like carbohydrates, is also a source of calories, but it provides a whopping nine calories per gram, compared to the measly four calories you get from carbs and protein. This means, head to head, fat is always a more efficient source of energy than carbohydrates.

On the keto diet, instead of using glycolysis for energy, fatty acids are broken down into three types of ketones that provide energy to all your body’s cells:

• Acetoacetate: The main ketone made by your liver.
• β-hydroxybutyric acid: The main ketone in your bloodstream and the source of ketones’ anti-inflammatory benefits.
• Acetone: The least common ketone; it doesn’t provide energy, but it is responsible for carrying waste out of the body. It’s responsible for keto breath (the fruity or moldy breath that some people have when in ketosis) because it’s ridding the body of excess acetone through the lungs.

Importantly, fatty acids not only make ketones but also are able to produce glucose if you aren’t getting it from your diet. That’s why, even on the keto diet, your blood sugar levels don’t drop precipitously. They also don’t rise astronomically, as they do on a carb-rich diet, every time you take a bite of food.

The liver, the workhorse of metabolism, can’t use ketones as its energy source, so it’s crucial that fat can be turned into glucose to support the liver during ketosis. Like glucose, ketones are also a source of energy for the brain and provide its fuel during ketosis. Ketones may be better brain fuel than carbohydrates because they’ve been shown to improve the health of our brain cells and may be helpful in preventing neurodegenerative diseases like Alzheimer’s.

The words ketosis, ketogenesis, and ketogenic are all derived from a similar root, meaning to produce and utilize ketone bodies as the primary form of energy. That’s where the names ketogenic diet and keto diet come from!