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The ketogenic diet (or keto diet) has become very popular lately because of its potential to help with weight loss, eliminate cravings, and improve mental clarity. Everyone from Mark Sisson to Dr. Mercola to Dave Asprey is singing its praises, and some people claim it can even cure cancer.
It is one of the topics I always get lots of questions about because there are many different ways of doing it. Yes, it is possible to do it healthfully … and yes, it is possible to turn it into another fad diet while eating a lot of unhealthy foods. (No, you cannot eat only bacon and be healthy!)
In this post, I will cover the science behind the ketogenic diet and the best way to do it.
What Is the Ketogenic Diet?
Broadly speaking, a ketogenic diet is a diet that is sufficiently a) high in fat and b) low in carbohydrates and proteins to force the body to rely on fat instead of carbohydrates for energy. Originally it was used in the 1920s to treat severe cases of epilepsy in children, though now many people use variations of it for other outcomes.
A ketogenic diet puts the body in a state of ketosis, where the primary fuel for the body is a broken down product of fat called ketone bodies. Ketosis can occur through reduction of carbohydrates in the diet or through fasting (or through taking an external ketone-producing product). It is the liver that produces ketone bodies by breaking down fatty acids, either from body fat or the fat that we eat.
This is in contrast to the body’s fuel source when not in ketosis: carbohydrates, which the body breaks down into glucose.
It is important to note that there is a difference between burning dietary fat for fuel and getting the body to utilize stored fat. More on that later.
What Does a Healthy Keto Diet Look Like?
This is an interesting question and there are hundreds of opinions about the best answer.
A typical low carbohydrate diet may simply focus on limiting carbohydrate with liberal amounts of other foods, without a specific emphasis on fats. It is easy to be eating mostly meats and any other non-carbohydrate foods for a low carbohydrate diet, and not get into ketosis.
So what’s different? The ketogenic diet goes a step further and limits protein as well in order to achieve ketosis. According to Dr. Daniel Pompa, a ketogenic diet is comprised of:
- 65 – 80% of calories from fat
- 10 – 15% of calories from proteins (0.5 gram per lb of lean body mass)
- the remaining 5 – 10% calories from carbohydrates.
In short, it is critical to use liberal amount of fat and limit protein and carbohydrate intake in order to achieve ketosis.
Consider a 135-pound woman who has about 25% body fat and 100 lb of lean mass. If she follows a 2,000 calorie diet, she would be eating between 145 – 179 grams of fat, 50 grams of protein, and between 50 – 124 grams of carbohydrates (depending on her activity level). She would need to keep her carbohydrates under 50 grams a day in order to “keto-adapt” (for her body to adapt to using fat as the primary fuel).
Also note that this model is not a “bacon-only” type diet and should include copious amounts of non-starchy vegetables for fiber and micronutrients.
How to Eat Keto
Ideally, a keto diet should be assembled with whole and nutritious foods that do not cause inflammation. This means that the 5-10% of the carbohydrates would be from vegetables, nuts, and seeds rather than another source of starch.
On a keto-type diet, the plate should consist of mostly non-starchy vegetables, a reasonable portion of meat (about 3 ounces), and a liberal amount of good fats. The fats can be nuts, seeds, olive oil, avocados, avocado oil, pastured lard or bacon, grass-fed butter, MCT oil, or a condiment like a healthy mayo made from these.
Once a person is keto-adapted, the appetite is often regulated. Rather than feeling deprived, it is natural to feel less hungry overall and naturally inclined to go without eating for 12 hours overnight. This form of extended fasting may provide some added health benefits as well.
Why Do the Ketogenic Diet?
Not only have ketogenic diets been successfully used as a treatment for epilepsy for nearly a century, but it also has many potential health benefits even healthy people can use.
As Mark Sisson puts it, doing a keto reset restores our “factory settings,” which is our flexibility to alternate between different types of fuels and stored fats for energy, depending on what’s available. This flexibility has allowed humans to thrive for millions of years because hunter-gatherers didn’t always have access to constant abundance and variety of foods that we have today.
As it turns out, this flexibility is actually important for health. The biochemical pathways that ketogenic diets turn on have anti-aging effects and can even eradicate many modern diseases.
In fact, research shows ketogenic diets provide health benefits by:
- stabilizing blood sugar and lowering insulin
- reducing oxidative stress
- improving the number of mitochondria and making them function better
- providing our cells with ketone bodies, which is a cleaner-burning fuel than glucose
- activating a cellular clean-up process called autophagy, where the cells break down old and broken parts into reusable nutrients
- activating anti-aging and anti-inflammatory biochemical pathways.
5 Major Health Benefits of a Ketogenic Diet
When done correctly, the ketogenic diet may help:
1. Improve Metabolic Health from Lowered Blood Sugar
When we switch from burning glucose to burning ketones for energy, the blood sugar and insulin fluctuate much less than when we rely on carbohydrates for energy. The liver can constantly supply just enough glucose in the blood to keep the brain going.
Stabilizing blood sugar has many health benefits, including:
- reducing the risk of metabolic syndrome and diabetes
- helping with conditions due to high blood sugar like polycystic ovarian syndrome
- reducing the stress on the body (because there is no need for the stress hormones like cortisol and adrenaline to step in to maintain blood sugar). This makes balancing hormones easier.
- reducing and maybe even clearing up acne (because acne is a sign of too much insulin)
A Note on Blood Sugar
If you monitor your fasting blood glucose in the morning when you are in ketosis (more on how and why to do that in a bit), be aware you may experience elevated morning blood sugar due to a surge of cortisol and adrenaline. This is known as “the dawn phenomenon” and should decline to healthy levels during the day and improve over time.
According to Chris Kresser, post-meal blood sugar is the best time to detect blood sugar problems. In addition, one should never rely on one single test to diagnose a health issue.
2. Reduce Appetite and Cravings
It’s true … ketone bodies can suppress appetite by acting on the hypothalamus in the brain. In addition, the stabilized blood sugar can help reduce hunger and food cravings. Lastly, high-fat meals can stimulate a hormone that increase satiety in the gut.
As a result, many people on ketogenic diets find that they are much less hungry and no longer craving the high-carbohydrate foods they used to love. They can even skip meals or fast for days and won’t really be bothered by the hunger. (Imagine!)
3. Improve Brain Function and Protect Neurons
In many ways, the ketogenic diet is very good for the brain. Users report that it helps improve cognitive function, slows down the progression of neurodegenerative diseases, and may even protect from such diseases.
Here are some of the ways ketosis benefits the brain:
Ketosis Provides a Steady Supply of Clean-Burning Fuel to the Brain
Because the brain is the most energy-demanding organ in the body, it is extremely sensitive to the fluctuation of available fuels. People who regularly go through blood sugar rollercoasters often experience brain-based symptoms of low blood sugar, such as anxiety and fatigue when blood sugar dips low.
Being in ketosis can help prevent this from happening. For many women, stabilizing blood sugar has a mood-stabilizing effect.
According to Psychology Today, several studies suggest that ketogenic diets can help stabilize mental illnesses, sometimes even more powerfully than medications. Ketogenic diets reduce the symptoms of anxiety and depression in rats and mice, while many small clinical studies demonstrate that ketogenic diet can help stabilize schizophrenia.
In my own experience, I find that I am highly productive, calm and focused when in a state of ketosis (as measured by blood ketone and breath acetone levels).
Ketosis Supports Mitochondria Health and Reduces Inflammation
Before the discovery of neuroplasticity, scientists believed that a damaged brain cannot regenerate. However, by improving mitochondria health, reducing inflammation, and stimulating cellular cleanup, ketogenic diets can help a damaged brain repair itself. Thus, the ketogenic diet is almost a miracle for many brain diseases that were thought of as incurable.
Studies are emerging that ketogenic diets (in conjunction with other treatments) can either reverse progressive brain disorders or help repair the damage. These include traumatic brain injuries and neurodegenerative diseases like Alzheimer’s and Parkinson’s. The Wahl’s Protocol also utilizes this benefit of the ketogenic diet to help repair neurological damage from multiple sclerosis.
4. Slow Down Aging
Want to slow down the clock? The keto diet might be the one to try.
Ketosis Turns on the Anti-Aging Genes
Ketosis, similarly to fasting or caloric restriction, turns on a group of genes called Sirtuins. When scientists activate Sirtuins in animals, they found that these animals live longer. In addition, Sirtuins can help keep you lean and energetic during the day and sleeping well at night. More research is needed to know if this effect is the same in humans, but evidence seems strong that spending some time in ketosis is beneficial.
Ketosis Reduces Oxidative Damage
Oxidation is what causes steel to rust and apples to turn brown when they are exposed to air. Inside our bodies, oxidation helps our immune cells kill off germs and makes us tired at the end of the day. However, excess oxidation can cause aging and DNA damage.
By reducing blood sugar, ketosis significantly reduces the oxidative stress in the body. Glucose is an oxidizing sugar because an exposed oxygen of glucose can attack other molecules and damage them. These damaged proteins are called advanced glycation end products (AGEs).
People with high blood sugar will have a lot of AGEs and therefore age faster.
In addition, studies show ketosis turns on antioxidant genes and increases levels of cellular antioxidants like glutathione.
Ketosis Stimulates Autophagy (Cellular Cleanup)
Ketosis and fasting also activates an anti-aging cellular cleanup process called autophagy (auto = self, phagy = eat). Autophagy is when a cell eats its own defective parts in order to recycle nutrients and keep the different parts functioning like new. In addition, autophagy can protect against neurodegenerative diseases, viral and bacteria infections, and cancers.
5. Protect Against Cancer
Everyone has emerging cancer cells, but the cells can only develop into full-blown cancers if the body fails to kill off them off. DNA damage, inflammation, poor cellular cleanup, high blood sugar, and inability of the immune system to kill emerging cancer cells together lead to cancers. Proponents claim that ketogenic diets may help prevent cancers by addressing all of these aspects.
Ketogenic diets reduce oxidative stress and inflammation, stimulate cellular cleanup, reduce blood sugar, and stimulate the cancer-killing immune responses. In addition, ketogenic diets capitalize on the fact that cancer cells cannot feed on ketones.
Healthy cells have the choice to rely on glucose or other fuels and whether to use the mitochondria. In contrast, according to the 1931 Nobel Laureate Otto Warburg, cancer cells lack the ability to use ketones for energy. They can only generate energy by burning glucose and glutamine for energy.
Since the state of ketosis forces cells to rely on ketones and to use the mitochondria for energy, ketosis feeds healthy cells while starving cancer cells. This especially seems to be true against some of the most deadly and incurable cancers. Researchers like Dr. Dom D’Agostino are also researching the role of ketosis and fasting in improving the outcomes and reducing the side effects of existing cancer treatments.
6 Common Ketogenic Diet Mistakes
A ketogenic diet has many health benefits. However, it is possible to make mistakes that can hinder them from achieving their goals.
1. Too Much Dairy
It’s not a good idea to include a lot of dairy in a ketogenic diet because the protein in dairy can deactivate Sirtuin, the anti-aging pathway, and create an insulin spike. While butter and ghee (from quality pastured sources) generally don’t cause this effect, high-fat cheeses and heavy creams do. In addition, dairy products can be inflammatory for many people.
If you tolerate dairy then enjoy some in your diet, but don’t rely on a liberal amount of cheeses or heavy cream as a source of fat. I personally believe that raw, pastured, and organic dairy is best, but limit it in my diet.
2. Too Much Protein
Being in a ketogenic diet is muscle-sparing, so you need much less protein than you would if you rely on carbohydrates or proteins for energy.
Amino acids can be converted into sugar and burned as energy. In addition, high intake of protein can turn off the anti-aging and anti-cancer processes in our cells, so it is best to only eat just enough protein on a ketogenic diet.
3. Starving the Good Gut Bacteria
Eating very little or no carbohydrates can starve your good gut bacteria. This can’t be good for health!
Studies have shown that food composition influences the gut bacteria much more than any probiotic supplements. It is therefore very important to feed your gut bacteria while you are on a ketogenic diet.
Resistant starches can be included as part of a ketogenic diet or as a supplement because it has minimal effects on blood sugar, so it doesn’t disrupt the state of ketosis. Resistant starches not only feed good bacteria in the gut but can also get fermented into substances that are beneficial for health. (Read this post to learn more about the health benefits of resistant starches and how to use them.)
Vegetables also contain a lot of fiber that can feed the gut bacteria and provide an important source of vitamins, minerals, and phytonutrients. In my opinion, it is absolutely vital to eat a wide variety of non-starchy vegetables on a keto diet to protect gut bacteria!
4. Eating Too Much
Many health benefits of the ketogenic diet mentioned above are as a result of activating our survival genes. To reap full health benefits from the ketogenic diet, it is important that you don’t tell your body that there is an abundant of foods.
According to Dr. Daniel Pompa, it is also important to be in a caloric deficit if one goes on a ketogenic diet to treat neurological diseases or cancers.
If your goal is weight loss, it is still important to be in a caloric deficit as simply cutting carbohydrates alone won’t be enough for fat loss.
As Mark Sisson says, always be asking yourself if you really are hungry for the next bite.
5. Not Getting Enough Salt and Minerals
Salt gets a bad rep as unhealthy, but it provides a very important mineral. Being in ketosis causes the body to excrete more salt, so it is important to ensure that to eat extra salt and mineral supplements as necessary.
6. Not Eating Enough Non-Starchy Vegetables
As mentioned above, not getting enough fiber from vegetables can starve gut bacteria. The keto diet is not a meat, egg, and cheese diet, though many treat it this way. Most of us aren’t getting enough vegetables anyway and this can be an easy trap to fall into on a keto diet.
Eating a Ketogenic Diet Is Not About Deprivation
Remember, though, that this is not about deprivation. Rather, it is about finding the sweet spot where you feel good and without excessive hunger or craving. Everybody is different, so it will be important to experiment in order to find your sweet spot.
Most people, including Mark Sisson himself, do better when they always include some natural sources of carbohydrates (e.g., lots of vegetables) and occasionally add starchy carbohydrates to their diet.
The good news is, it is not necessary to stay on a ketogenic diet at all times to reap this benefit. Our ancestors went through fast and feast cycles and the body is designed for flexibility. We may be able to reduce cancer risk, prolong life, improve brain function, and benefit from ketosis otherwise by being in ketosis or fasting a few days a week.
Is Keto Good for Women?
In general, men tend to do better on a long term ketogenic diet than women do. From my own research and experimentation, women can follow a keto diet, but with some adaptions. Most women will do well with a cyclical ketogenic diet when they stay on ketogenic diet most of the time and eat starchy carbohydrates occasionally to spike calories and carbs.
Dr. Daniel Pompa recommends at least one “feast” day a week for women where carbohydrates and calories are both increased, as well as up to seven days once a month with increased carbs (often during the menstrual cycle).
Ketogenic Diet Cautions
Ketogenic diets are not for everyone. There are some people who should be very careful with the ketogenic diet, or at least should not do it without medical supervision. While I understand not many mainstream doctors will be well versed in the ketogenic diet, there are online services that can pair you with a primary care doctor who understands keto in detail.
Type 1 Diabetics
Type 1 diabetics are dependent on insulin injections to manage their blood sugar and are at risk for ketoacidosis, which as a life-threatening condition where there is dangerously high levels of ketones — much higher than a healthy person in ketosis can actually achieve — in their blood.
People with ApoE4/E4 or ApoE3/E4 Genes
ApoE stands for Apolipoprotein E, which is a protein that transports fats and cholesterol in the body. There are three variants of this gene: E2, E3, and E4. Everyone has two copies, so you can have any combination of these variants.
People with two copies of the E4 variant (ApoE4/E4) often don’t respond well to saturated fats. These people will have very high cholesterol and it tends to run in their families. These are a small subset of the population that have to be careful with the ketogenic diet.
If you have these genes (here’s one way to test for them), be sure to monitor your blood lipids if you were to go on a ketogenic diet. In addition, focus on monounsaturated fats such as those found in avocados or olives rather than saturated fats or MCT oil.
For anyone else, it is a good idea to monitor your blood tests when you start out with a ketogenic diet.
Pregnant and Breastfeeding Moms
This is a controversial one as many doctors believe that the baby needs carbohydrates to develop, and many moms need carbohydrates in order to produce milk. However, dietician Lily Nichols believes that a healthy ketogenic diet is safe for pregnant women and that it is easier to get into ketosis during pregnancy.
Perhaps the best approach is to listen to your body, because every pregnancy is different. If you choose to get on a ketogenic diet during pregnancy or breastfeeding, be sure to consult your healthcare practitioner to ensure that you do it safely.
Women Who Struggle with Irregular Cycles and Fertility
Being in ketosis and fasting can turn on the survival genes in the body and causes the body to attempt to conserve energy. For some women, this can cause irregular cycles and infertility.
A ketogenic diet may help with infertility due to polycystic ovarian syndrome because it is partly caused by insulin resistance. However, the ketogenic diet can make irregular cycles and infertility worse for women who struggle with it from other causes, including stress and over-exercise.
Strength and High-Intensity Athletes
Lifting heavy things and high-intensity exercises utilizes mainly carbohydrates. Many strength trainees and athletes will find that their performance drop significantly when they are on a ketogenic diet.
If you have been keto-adapted for years, your body can eventually adapt to generate the carbohydrates you need to fuel these activities. However, if you are relatively new to ketosis and need to perform athletically, then perhaps going full ketosis may not be such a good idea.
How to Get Started with a Ketogenic Diet
If you’ve determined the ketogenic diet might be for you, I recommend this podcast with Mark Sisson for a great introduction. His book The Keto Reset Diet explains the benefits and cautions in detail, as well as exactly how to get started.
Another easy way to start planning a ketogenic diet is to use Real Plans. Not only can this meal planning app filter recipes to avoid most any food allergy, it also can generate a keto-friendly meal plan and shopping list.
Getting into Ketosis
Unless you’ve already been eating a paleo or primal diet and are somewhat keto-adapted (burning ketones for fuel), it is a good idea “reset” the body in order to regain the metabolic flexibility to go into ketosis or even stay in ketosis despite eating some carbohydrates. Intermittent fasting is one efficient way to do this. During a water fast, ketosis can occur in days instead of weeks or months and often sustains for a while after the fast.
Being in ketosis has many health benefits but also some potential side effects. In order to maximize the health benefits, you should:
- Assemble your diet from whole foods as much as possible (especially green vegetables and healthy fats like avocado and olives)
- Ensure that you maintain a nutrient-dense diet by including organ meats, vegetables, and some low-carbohydrate fruits in your diet
- Limit protein intake, as protein can still get converted into glucose and high protein intakes can oppose the positive effects of a ketogenic diet
- Eat just enough to satiation
Using Testing to Improve Keto Diet Outcomes
It is entirely possible to follow a low-carbohydrate diet or keto diet and not be in ketosis. When I’ve personally experimented with ketosis, I used various methods of testing to make sure my ketone levels and blood glucose levels were within healthy ranges:
Blood Ketone & Glucose Testing
I used the Keto Mojo meter (and blood glucose strips) which tests both blood ketone levels and blood glucose levels. More on this soon in an upcoming post about fasting, but I testing fasting morning glucose and post-meal glucose at one hour. I also tested fasted morning ketones and evening ketones.
Breath Acetone Testing
Another way to test the body’s response to nutritional ketosis is through breath acetone levels. This essentially shows how much of the ketones are being utilized by the body. I used a Levl meter (use the code wellnessmama at this link for $25 off) to test breath acetone levels. This device is more pricey but does not require strips so it can be used more often. I used it to test my response to certain foods or exercises and to see if they pulled me out of ketosis.
Bottom Line: What I Do
The keto diet is not the Atkins diet, or an all-meat diet, or anything close. A healthy version should include an abundance of non-starchy vegetables and healthy fats from various sources.
The more I learn, the more I am convinced that variation is one of the biggest factors in health. The ketogenic diet can be a useful tool, but in my opinion it should be cycled and should include occasional days with extra carbohydrates from good sources.
I most often experiment with keto in the winter when food would have traditionally been more scarce and carbohydrates harder to find. During these times, the majority of my plate is still mostly green vegetables and I make a very conscious effort to consume a wide variety of vegetables.
From testing, I personally enter ketosis much more efficiently when fasting and will be sharing my experiences on this soon.
This article was medically reviewed by Dr. Scott Soerries, MD, Family Physician and Medical Director of SteadyMD. As always, this is not personal medical advice and we recommend that you talk with your doctor.
Have you tried a ketogenic diet? What’s your experience? Please share in the comments below.