Unlike many fad diets that come and go with very limited rates of long-term success, the ketogenic diet (or keto diet) has been practiced for more than nine decades (since the 1920s) and is based upon a solid understanding of physiology and nutrition science.
The keto diet works for such a high percentage of people because it targets several key, underlying causes of weight gain — including hormonal imbalances, especially insulin resistance coupled with high blood sugar levels, and the cycle of restricting and “binging” on empty calories due to hunger that so many dieters struggle with. Yet that’s not a problem with what’s on the keto diet food list.
What is the keto diet? Rather than relying on counting calories, limiting portion sizes, resorting to extreme exercise or requiring lots of willpower (even in the face of drastically low energy levels), the ketogenic, low-carb diet takes an entirely different approach to weight loss and health improvements. It works because it changes the very “fuel source” that the body uses to stay energized: namely, from burning glucose (or sugar) to dietary fat, courtesy of keto recipes and the ketogenic diet food list items, including high-fat, low-carb diet foods.
Making that switch will place your body in a state of “ketosis,” when your body becomes a fat burner rather than a sugar burner. The steps are surprising simple:
- Cut down on carbs.
- Increase your consumption of healthy fats.
- Without glucose coursing through your body, it’s now forced to burn fat and produce ketones instead.
- Once the blood levels of ketones rise to a certain point, you officially reach ketosis.
- This state results in consistent, fairly quick weight loss until your body reaches a healthy and stable weight.
The Ketogenic Diet Beginner’s Guide
The classic ketogenic diet is a very low-carb diet plan that was originally designed in the 1920s for patients with epilepsy by researchers working at Johns Hopkins Medical Center. (1) Researchers found that fasting — avoiding consumption of all foods for a brief period of time (such as with intermittent fasting), including those that provide carbohydrates — helped reduce the amount of seizures patients suffered, in addition to having other positive effects on body fat, blood sugar, cholesterol and hunger levels. (2)
Unfortunately, long-term fasting is not a feasible option for more than a few days, therefore the ketogenic diet was developed to mimic the same beneficial effects of fasting. Essentially the keto diet works by “tricking” the body into thinking it is fasting, through a strict elimination of glucose that is found in carbohydrate foods. Today the standard ketogenic diet goes by several different names, including the “no-carb diet” or “very low carbohydrate ketogenic diet”(LCKD or VLCKD for short).
At the core of the classic ketogenic diet is severely restricting intake of all or most foods with sugar and starch (carbohydrates). These foods are broken down into sugar (insulin and glucose) in our blood once we eat them, and if these levels become too high, extra calories are much more easily stored as body fat and results in unwanted weight gain. However, when glucose levels are cut off due to low-carb dieting, the body starts to burn fat instead and produces ketones that can be measured in the blood (using urine strips, for example).
Ketogenic diets, like most low carb diets, work through the elimination of glucose. Because most folks live on a high carb diet, our bodies normally run on glucose (or sugar) for energy. We cannot make glucose and only have about 24 hours’ worth stored in our muscle tissue and liver. Once glucose is no longer available from food sources, we begin to burn stored fat instead, or fat from our diets.
Therefore, when you’re following a ketogenic diet, your body is burning fat for energy rather than carbohydrates, so in the process most people lose weight and excess body fat rapidly, even when consuming lots of fat and adequate calories through their diet. Another major benefit of the keto diet is that there’s no need to count calories, feel hungry or attempt to burn loads of calories through hours of intense exercise.
In some ways, it’s similar to the Atkins diet, which similarly boosts the body’s fat-burning abilities through eating only low-carb foods, along with getting rid of foods high in carbs and sugar. Removing glucose from carbohydrate foods will cause the body to burn fat for energy instead. The major differences between the classic keto diet and the Atkins diet is ketogenic emphasizes healthier fats, less overall protein and no processed meat (such as bacon) while having more research to back up its efficacy.
What Is Ketosis?
Ketosis is the result of following the standard ketogenic diet, which is why it’s also sometimes called “the ketosis diet.” Ketosis takes place when glucose from carbohydrate foods (like grains, all sources of sugar or fruit, for example) is drastically reduced, which forces the body to find an alternative fuel source: fat. Ketosis can also be achieved by multiple days of total fasting, but that isn’t sustainable beyond a few days. (It’s why some keto diet plans combine intermittent fasting or IMF with the keto diet for greater weight loss effects.)
Although dietary fat (especially saturated fat) often gets a bad name, provoking fear of weight gain and heart disease, it’s also your body’s second preferred source of energy when carbohydrates are not easily accessible.
In the absence of glucose, which is normally used by cells as a quick source of energy, the body starts to burn fat and produces ketone bodies instead. Once ketone levels in the blood rise to a certain point, you enter into a state of ketosis — which usually results in quick and consistent weight loss until you reach a healthy, stable body weight.
To sum up a complex process, you reach ketosis when the the liver breaks down fat into fatty acids and glycerol, through a process called beta-oxidation. There are three primary types of ketone bodies that are water-soluble molecules produced in the liver: acetoacetate, beta-hydroxybutyrate and acetone.
The body then further breaks down these fatty acids into an energy-rich substance called ketones that circulate through the bloodstream. Fatty acid molecules are broken down through the process called ketogenesis, and a specific ketone body called acetoacetate is formed which supplies energy.
The end result is staying fueled off of circulating high ketones (which are also sometimes called ketone bodies) — which is what’s responsible for altering your metabolism in a way that some people like to say turns you into a “fat-burning machine.” Both in terms of how it feels physically and mentally, along with the impact it has on the body, being in ketosis is a very different than a “glycolytic state,” where blood glucose (sugar) serves as the body’s energy source.
So, is ketosis bad for you? Absolutely not. If anything, it’s the reverse. Many consider ketosis and burning ketones to be a much “cleaner” way to stay energized compared to running on carbs and sugar day in and day out.
And remember, this ketosis state is not to be confused with ketoacidosis, which is a serious diabetes complication when the body produces excess ketones (or blood acids).
The goal of the ketogenic diet is to keep you in this fat-burning metabolic state of ketosis, in which you will lose weight until you reach your ideal set point.
How Do You Get Into Ketosis?
Here’s how it works:
- Consumption of glucose from carbohydrate foods — grains, starchy vegetables, fruit, etc. — is cut way down.
- This forces your body to find an alternative fuel source: fat (think avocados, coconut oil, salmon).
- Meanwhile, in the absence of glucose, the body also starts to burn fat and produces ketones instead.
- Once ketone levels in the blood rise to a certain point, you enter into a state of ketosis.
- This state of high ketone levels results in quick and consistent weight loss until you reach a healthy, stable body weight.
Wondering how many carb foods you can eat and still be “in ketosis”? The traditional ketogenic diet created for those with epilepsy consisted of getting about 75 percent of calories from sources of fat (such as oils or fattier cuts of meat), 5 percent from carbohydrates and 20 percent from protein. For most people a less strict ketogenic diet (what I call a “modified keto diet”) can still help promote weight loss in a safe, and often very fast, way.
In order to transition and remain in ketosis, aiming for about 30–50 net grams is typically the recommended amount of total carbs to start with. This is considered a more moderate or flexible approach but can be less overwhelming to begin with. Once you’re more accustomed to “eating keto,” you can choose to lower carbs even more if you’d like (perhaps only from time to time), down to about 20 grams of net carbs daily. This is considered the standard, “strict” amount that many keto dieters aim to adhere to for best results, but remember that everyone is a bit different.
What Are the Stages of Ketosis?
Once ketone levels in the blood rise to a certain point, you officially enter into a state of ketosis. This state results in fairly rapid and consistent weight loss until you reach a healthier (and stable) body weight. Overall, people enter into ketosis at different rates, usually after 3–4 days of fasting or following a very low-carbohydrate diet (20 grams of net carbs or less) that forces the need for an alternative energy source. (3)
Ketosis occurs when the liver breaks down fat into fatty acids and glycerol — a process called beta-oxidation. In particular, three primary types of ketone bodies that are water-soluble molecules are produced: acetoacetate, beta-hydroxybutyrate and acetone.
Rather than drawing energy from glucose, a person in ketosis stays fueled off of these circulating ketones or ketone bodies — essentially, burning fat for fuel. This is the principal goal of the ketogenic diet, which can be achieved by adhering to a very low-carbohydrate, high-fat diet with only moderate amounts of protein.
Optimal ketosis is reached when they body stays in ketosis for at least a few weeks, when any type of side effects diminish greatly while the benefits are more pronounced with the body becoming a fat burner.
What Is a Keto Food? What Does a Keto Meal Look Like?
Here are examples of high-fat, low-carb foods on the ketogenic diet food list:
- Your keto meals should contain high amounts of healthy fats (up to 80 percent of your total calories!), such as olive oil, coconut oil, grass-fed butter, palm oil, and some nuts and seeds. Fats are a critical part of every ketogenic recipe because fat is what provides energy and prevents hunger, weakness and fatigue.
- Keto meals also need all sorts of non-starchy vegetables. What vegetables can you eat on a ketogenic diet without worrying about increasing your carb intake too much? Some of the most popular choices include broccoli and other cruciferous veggies, all types of leafy greens, asparagus, cucumber, and zucchini.
- In more moderate amounts, foods that are high in protein but low- or no-carb, including grass-fed meat, pasture-raised poultry, cage-free eggs, bone broth, wild-caught fish, organ meats and some full-fat (ideally raw) dairy products.
On the other hand, the types of foods you’ll avoid eating on the keto, low-carb diet are likely the same ones you are, or previously were, accustomed to getting lots of your daily calories from before starting this way of eating. This includes items like fruit, processed foods or drinks high in sugar, those made with any grains or white/wheat flour, conventional dairy products, desserts, and many other high-carb foods (especially those that are sources of “empty calories”).
6 Benefits of the Ketogenic Diet
1. Weight loss
On a keto diet, weight loss can often be substantial and happen quickly (especially for those who start the diet very overweight or obese). The 2013 study published in the British Journal of Nutrition found that those following a keto diet “achieved better long-term body weight and cardiovascular risk factor management when compared with individuals assigned to a conventional low-fat diet (i.e. a restricted-energy diet with less than 30 percent of energy from fat).” (4)
A 2014 review published in the International Journal of Environmental Research & Public Health states:
One of the most studied strategies in the recent years for weight loss is the ketogenic diet. Many studies have shown that this kind of nutritional approach has a solid physiological and biochemical basis and is able to induce effective weight loss along with improvement in several cardiovascular risk parameters. (5)
High-fat, low-carb diets can help diminish hunger and also boost weight loss through their hormonal effects. As described above, when we eat very little foods that supply us with carbohydrates, we release less insulin. With lower insulin levels, the body doesn’t store extra energy in the form of fat for later use, and instead is able to reach into existing fat stores for energy.
Diets high in healthy fats and protein also tend to be very filling, which can help reduce overeating of empty calories, sweets and junk foods. (6) For most people eating a healthy low-carb diet, it’s easy to consume an appropriate amount of calories, but not too many, since things like sugary drinks, cookies, bread, cereals, ice cream or other desserts and snack bars are off-limits.
2. Reduce Risk for Type 2 Diabetes
This process of burning fat provides more benefits than simply helping us to shed extra weight — it also helps control the release of hormones like insulin, which plays a role in development of diabetes and other health problems. When we eat carbohydrates, insulin is released as a reaction to elevated blood glucose (an increase in sugar circulating in our blood) and insulin levels rise. Insulin is a “storage hormone” that signals cells to store as much available energy as possible, initially as glycogen (aka stored carbohydrates in our muscles) and then as body fat.
The ketogenic diet works by eliminating carbohydrates from the diet and keeping the body’s carbohydrate stores almost empty, therefore preventing too much insulin from being released following food consumption and creating normal blood sugar levels. This can help reverse “insulin resistance,” which is the underlying problem contributing to diabetes symptoms. In studies, low-carb diets have shown benefits for improving blood pressure, postprandial glycemia and insulin secretion. (7) Therefore, diabetics on insulin should contact their medical provider prior to starting a ketogenic diet, however, as insulin dosages may need to be adjusted.
3. Reduce Risk of Heart Disease
The keto diet can reduce the risk of heart disease markers, including high cholesterol and triglycerides. (8) In fact, the keto diet is unlikely to negatively impact your cholesterol levels despite being so high in fat. Moreover, it’s capable of lowering cardiovascular disease risk factors, especially in those who are obese. (9)
One study, for example, found that adhering to the ketogenic diet and keto diet food list for 24 weeks resulted in decreased levels of triglycerides, LDL cholesterol and blood glucose in a significant percentage of patients, while at the same time increasing the level of HDL cholesterol. (10)
4. Help Protect Against Cancer
Certain studies suggest that ketogenic diets may “starve” cancer cells. A highly processed, pro-inflammatory, low-nutrient diet can feed cancer cells causing them to proliferate. What’s the connection between a high-sugar diet and cancer? The regular cells found in our bodies are able to use fat for energy, but it’s believed that cancer cells cannot metabolically shift to use fat rather than glucose. (11)
There are several medical studies — such as two conducted by the Department of Radiation Oncology at the Holden Comprehensive Cancer Center for the University of Iowa, and the National Institutes of Health’s National Institute of Neurological Disorders and Stroke, for example — that show the ketogenic diet is an effective treatment for cancer and other serious health problems. (12)
Therefore, a diet that eliminates excess refined sugar and other processed carbohydrates may be effective in reducing or fighting cancer. It’s not a coincidence that some of the best cancer-fighting foods are on the ketogenic diet food list.
5. Fight Brain Disease & Neurological Disorders
Over the past century, ketogenic diets have also been used to treat and even help reverse neurological disorders and cognitive impairments, including epilepsy and Alzheimer’s symptoms. Research shows that cutting off glucose levels with a very low-carb diet makes your body produce ketones for fuel. This change can help to reverse neurological disorders and cognitive impairment, including inducing seizure control. The brain is able to use this alternative source of energy instead of the cellular energy pathways that aren’t functioning normally in patients with brain disorders.
A related clinical diet for drug-resistant epilepsy is called the medium-chain triglyceride ketogenic diet, in which MCT oil is extensively used because it’s more ketogenic than long-chain triglycerides. (13a) Another dietary therapy for epilepsy called Low Glycemic Index Treatment (LGIT) was developed in 2002 as an alternative to the ketogenic diet. LGIT monitors the total amount of carbohydrates consumed daily, and focuses on carbohydrates that have a low glycemic index.) (13b)
Clinical improvement was observed in Alzheimer’s patients fed a ketogenic diet, and this was marked by improved mitochondrial function. (14a) In fact, a European Journal of Clinical Nutrition study pointed to emerging data that suggested the therapeutic use of ketogenic diets for multiple neurological disorders beyond epilepsy and Alzheimer’s, including headaches, neurotrauma, Parkinson’s disease, sleep disorders, brain cancer, autism and multiple sclerosis. (14b)
The report goes on to say that while these various diseases are clearly different from each other, the ketogenic diet appears to be so effective for neurological problems because of its “neuroprotective effect” — as the keto appears to correct abnormalities in cellular energy usage, which is a common characteristic in many neurological disorders.
Researchers believe that the ketogenic diet can also help patients with schizophrenia to normalize the pathophysiological processes that are causing symptoms like delusions, hallucinations, lack of restraint and unpredictable behavior. One study found that the ketogenic diet lead to elevated concentrations of kynurenic acid (KYNA) in the hippocampus and striatum, which promotes neuroactive activity. Some studies even point to the elimination of gluten under the ketogenic diet as a possible reason for improved symptoms, as researchers observed that patients with schizophrenia tended to eat more carbohydrates immediately before a psychotic episode. (15)
Although the exact role of the ketogenic diet in mental and brain disorders is unclear, there has been proof of its efficacy in patients with schizophrenia. And, to boot, the ketogenic diet works to reverse many conditions that develop as a side effect of conventional medications for brain disorders, like weight gain, type 2 diabetes and cardiovascular risks. More research is needed to understand the role of the ketogenic diet in treating or improving schizophrenia, as the current available studies are either animal studies or case studies, but the benefits of a high fat, low carbohydrate diet in neurology is promising.
6. Live Longer
Now, there’s even evidence that a low-carb, high-fat diet helps you live longer, compared to a low-fat diet. In a study by the medical journal The Lancet that studied more than 135,000 adults from 18 countries, high carbohydrate intake was associated with higher risk of total mortality, whereas total fat and individual types of fat were related to lower total mortality. Total fat and types of fat were not associated with cardiovascular disease, myocardial infarction or cardiovascular disease mortality.
In fact, saturated fat intake had an inverse association with the risk for suffering from a stroke, meaning the more saturated fat included in someone’s diet, the more protection against having a stroke they seemed to have.