Is There a Dark Side of Ketosis?

Is There a Dark Side of Ketosis?

“That will totally knock me out of ketosis,” I heard someone say recently at a dinner party.

I can’t remember what appetizer she pointed to, but the woman sitting to the left of me said this so casually, and several folks at the table knew exactly what she meant, confirming what I’d long suspected: Ketogenic diets have officially gone mainstream – or recognizable at a party mainstream at least in 2017.

Let’s back up and demystify ketosis, which simply means you’re utilizing ketone bodies – more commonly called ketones – rather than glucose as your body’s primary fuel.

Just like your car uses gasoline, your body needs fuel. That usually means glucose. But let’s say you’re on a very-low carbohydrate, higher-fat diet. Your body doesn’t get a lot of glucose, which primarily comes from carbohydrate and to a lesser degree protein. That means your liver’s backup glucose (glycogen) also becomes in short supply.

Unlike your car, your body doesn’t just shut down. Thankfully, you have an alternative fuel source called ketones.

Ketones are organic compounds your liver always makes. You’re cranking out ketones right now as you read this. During starvation or (more likely) when you restrict carbohydrate and increase fat intake, your body uses ketones as its primary fuel.

In other words, when your body doesn’t receive or can’t make enough glucose, it shifts to this alternative fuel. Almost every organ can utilize ketones except for your red blood cells (which don’t have ketone-metabolizing mitochondria) and liver.

Your liver, in fact, does the heavy lifting. This hardworking organ metabolizes fat into three ketone bodies: acetoacetate (ACA), beta-hydroxybutyrate (BHB), and acetone.(1) BHB is the first substrate that kicks ketosis into action.

Among its benefits, BHB reduces chronic inflammation and restores healthy inflammation levels. In fact, researchers believe a ketogenic diet’s anti-inflammatory effects could be thanks to BHB.(2)

While you’ve got several ways to shift into ketosis (including intermittent fasting), probably the most popular involves a ketogenic diet, which is about 80 – 90 percent fat with moderate protein but very limited carbohydrate.(3)

You read that right: 80 to 90 percent. That’s a lot of fat; far more than most people eat. Because it high fat content shifts you into ketosis, your body thinks it’s starving, creating many of fasting’s benefits without actual starvation.

Wait, you mean you can eat scrambled eggs in coconut oil and a big sirloin steak slathered in butter with bernaise sauce to get lean and healthy? Emphatically, maybe: As with most things in life, nothing is as easy or perfect as it might initially seem.

Is Ketosis Dangerous?

Ask someone doing a ketogenic diet or check out one of many keto blogs and you’ll find devotees who swear ketosis is the magical bullet for weight loss, glowing health and feeling fabulous.

“Basically, a keto diet forces the body to use stored fat as its primary fuel source, rather than stored carbs, helping you slim down and find your hidden six-pack,” says Julian Bakery, which sells its own “instant ketones” product. (More on those in a minute.) “When you are in a ketogenic state, you become a hyper-efficient, fat-burning machine.”(4)

Hidden six-pack? (Sign me up.) Who doesn’t want to become a hyper-efficient, fat-burning machine?

But not everyone shares that enthusiasm. The next time you have a physical or otherwise see your physician or nurse practitioner, ask his or her thoughts about ketosis. Chances are, you’ll either get a blank stare, a stern warning about the dangers of ketosis, or (if they are nutrition-oriented) a “give it a shot.”

The “dangerous” theory still prevails among mainstream practitioners and, even in this dietary fat-enlightened age, many people still confuse dietary ketosis with diabetic ketoacidosis.

The latter condition occurs when low levels of insulin and high levels of counter-regulatory hormones create dangerously high levels of ketones.(5) Ketoacidosis occurs in people with Type I diabetes, and left untreated, it could result in coma or death. Yes, this should be taken seriously!

However, true Ketogenesis, which is not the same as diabetic ketoacidosis, means that your liver cells’ mitochondria are creating ketones. This happens all the time, but dialing down carbohydrates and focusing on a high-fat, moderate-protein diet means your body runs out of glucose so it shifts to ketosis as its primary fuel.

“A ketogenic diet produces, on average, 5 to 7 mmol/dl of ketones, and it does it in the presence of normal to low blood sugar,” writes Dr. Jonny Bowden in Living the Low Carb Life. “The untreated type 1 diabetic will produce ketones in the range of 25 (350 to 600 percent higher than normal!) and will do it in the presence of extraordinary high and dangerous levels of blood sugar.”

Ketosis, then, is simply a metabolic state in where your body utilizes fat (as ketones) as its primary fuel. When your body goes into ketosis, it becomes keto-adapted, meaning it favors fat and not carbohydrate (glucose) for fuel.

For most people, this condition is not dangerous, and it is an entirely different ballgame than ketoacidosis. If you have Type 1 diabetes, any kind of blood sugar imbalance, or potential other concerns, please confer with an integrative practitioner or other healthcare professional before you start a ketogenic diet. Do not undertake a high-fat diet if you have any concerns.

Getting and Staying in Ketosis

Let’s say you’ve got some weight to lose and get tired of lapsing into a sugar coma every afternoon at work. You’ve unsuccessfully tried other diets and want to give that “keto diet thing” a try.

First thing: You’ll hit up Whole Foods or your local grocery and stock up on healthy fat from things like grass-fed beef, pasture-raised eggs, wild-caught fish, and plant foods like avocado, coconut, nuts, and seeds.

You come home with your loot and promptly dump the sugary, flour-y, processed garbage that lurks in your kitchen. Goodbye, empty carbs; hello, healthy high-fat whole foods.

Especially if you’ve long adhered to a lower-fat diet, you’ll probably love this way of eating at first. Bacon and eggs for breakfast, a big salad with avocado and wild-caught salmon, macadamia nuts for a snack, and a grass-fed steak with broccoli for dinner.

You’ll probably rave to your friends and colleagues that your new “diet” doesn’t feel like a diet at all. Unlike other diets, you’re never hungry between meals, and if you are, you just grab a handful of nuts.

After a few days, you’ll probably be curious whether you’re in ketosis; in other words, whether you’ve shifted to that coveted fat-burning state. You’ve got two ways to know for sure: Urine strips or a glucose meter.

Urine strips offer a simple, fast and cheap analysis to measure ketone levels. Simply place the strip under a stream of urine, remove, shake off the excess urine, and wait a few seconds for the strip to change color. The strips come with a guide to explain each color’s meaning. Generally, the deeper the purple, the higher your ketone levels.

While relatively inexpensive and available at most drugstores or online, the main drawback of urine strips is lack of accuracy. Dehydration or over-hydration can create a false positive or false negative, respectively.

Ketones also take time to travel from your blood to urine, which make glucose meters (that measure blood levels of ketones) more accurate. They can be pricey, and do you really want to prick your finger or body several times a day?

Once you’re officially into ketosis (most people know without urine strips or a glucose meter), you’ll probably also start noticing your jeans fit a little looser. Indeed, studies show a ketogenic diet can help you lose weight by (among other factors) controlling hunger and improving your metabolism.(6)

Ketogenic diets also create health benefits. One study found a low-carbohydrate ketogenic diet improved glycemic control in patients with Type 2 diabetes. In fact, keto helped these 28 folks reduce or ditch their diabetes medications.(7) (If you have diabetes, do NOT change your medication regimens without working with your physician!)

Other studies show ketogenic diets can potentially benefit various conditions including cancer,(8) aging,(9) and brain health. (10)

However, amidst the “keto magic” there’s a downside. If those first few weeks sound too good to be true – you lose weight and get in better health all while eating formerly forbidden high-fat foods – you should know about ketosis drawbacks.

Before you got to that fat-burning, feel-better place, you probably suffered a few hurdles. You initially felt constipated. Then, a few days into ketosis, the opposite happened: You once had to bolt to the bathroom holding a downward dog in yoga. That wasn’t a fun moment. Oh, and your all-too-candid coworker complained you had bad breath.

As your body shifts into ketones as its primary fuel, you might also notice lagging energy and brain fog. Nutrient deficiencies sometimes occur and might play a part in these less-than-stellar feelings. One mice study, for instance, found ketogenic diets increases biotin deficiencies. Researchers concluded people on ketogenic diets have increased biotin requirements.(11) Yes, any diet can lead to deficiencies, and I recommend everyone use a quality multivitamin-mineral.

You’ve adjusted for all those variables, and three weeks in you’re finally sailing comfortably in keto-land. You visit your doctor, who raves about your 12-pound weight loss. You’re glowing until your blood work comes back and you get a phone call. Your doctor says your cholesterol and triglycerides have skyrocketed.

At this point, don’t panic. Studies show while serum lipid values sometimes increase during the first several months on a ketogenic diet, they decline to normal values by 12 months and remain normal on the diet for many years.(12)

I could go on, but my point is that keto – like any eating plan – isn’t perfect or the ideal solution for everyone. Overall, its benefits far outweigh its drawbacks, and for some people – emphasis on some – keto can become an ideal way to get lean and healthy.

Magical MCTs?

About six weeks into your ketogenic diet, you hit a roadblock. Weight loss hits a brick wall, your coworkers and family stop complimenting your new fabulousness, and you will snap if you have to eat another four-egg omelet or avocado.

Once you hit that plateau, you might be tempted to ditch your diet or “ramp up” ketosis. Chief among the ways to do the latter is medium-chain triglyceride (MCT) oil, a tasteless clear oil you can take by the spoonful or mix into your morning coffee.

Once an arcane supplement, Bulletproof Coffee – which blends coffee, grass-fed butter, with MCT oil – made this oil mainstream. My local Whole Foods recently prominently displayed their own 365 MCT oil brand among its protein powders and other supplements.

Medium-chain triglycerides (MCTs) – available in coconut oil but also as the aforementioned stand-alone oil – bypass fat metabolism and go straight to your liver, where they become converted to BHB. Studies show people who regularly use MCTs accumulate less body fat.(13)

Another found MCT oil combined with a weight loss plan can decrease body mass index (BMI) and increase overall fat mass loss.(14)

MCT oil could also benefit people with Type 2 diabetes. Researchers found compared with rats fed oils like lard and corn oil, those fed high amounts of MCT oil helped reduced inflammation and improved their insulin response.(15)

Whereas keto diets have long been used for epilepsy (16), one study found people with epilepsy could use MCT oil to manage seizures “without maintaining a strict ketogenic lifestyle.”(17)

MCTs might even help your brain work better. BHB can cross the blood–brain barrier and enter neuronal mitochondria, eventually creating your energy currency (adenosine triphosphate, or ATP).(18)

In one study, on separate days 20 people with Alzheimer’s or mild cognitive impairment consumed a drink containing emulsified MCTs or a placebo. The MCT group had significant increases in BHB 90 minutes after treatment when they took cognitive tests.(19)

Not every review concludes so glowingly. One recent mice study showed some favorable effects with a high-MCT oil diet, yet researchers found higher doses could be harmful in the long-term.(20)

Keep in mind you don’t have to use MCT oil to get or stay in ketosis. If you do, easy does it. Because it’s tasteless, overdoing MCT oil is very easy, and trust me when I say side effects (including diarrhea) can seriously ruin your morning.

Skip the Middleman with Exogenous Ketones?

Ketosis has become a buzzword, and manufacturers know you’re eager to dip your toe (or plunge head-first) into the keto pool. They also know you don’t have days to spend eating a high-fat diet or otherwise “working” to get into ketosis.

Remember earlier I said beta-hydroxybutyrate (BHB), one of the three ketones, is the first substrate that kicks ketosis into action? You can get its anti-inflammatory and other benefits by getting into ketosis, but why do the heavy lifting when you can buy a supplement to do it for you?

MCT oil can generate BHB, especially combined with a ketogenic diet. But as the aforementioned study showed, it takes a few hours to get there.(19) In today’s fast-faster mentality, who wants to wait hours or days?

Exogenous ketone supplements, which really exploded a few years ago, can supposedly help you cut in line.

These increasingly popular supplements take out the middleman and let you directly consume BHB, hence their name: Whereas your liver produces endogenous ketones, ketones produced via a supplement would be exogenous ketones (meaning your body does not make them).

Exogenous ketone supplements typically contain BHB plus another active ingredient like MCT powder (providing an additional bump in ketones) and perhaps other things like stevia (for flavor) or caffeine.

Their pitch goes: Within a very short period of time (as little as 30 minutes), you can hit therapeutic levels of ketones without MCT oil’s potential GI messiness or suffering the miseries of a high-fat diet.

“Taking exogenous ketones by way of betahydroxybutryate will rapidly get you into ketosis and force your body to start using a sustained energy source,” says the Perfect Keto website, which sells its own exogenous ketone product. “This essentially skips the whole ‘carb flu’ and few day period where you have to restrict carbohydrates.”(21)

In other words, rather than spend days getting into ketosis – suffering its potential aforementioned miseries and eating high-fat foods – these supplements supposedly shift your body into ketosis almost immediately even if you’re not eating a high-fat, low-carb diet.

“Put Your Body in Ketosis in 59 Minutes or Less,” promises Keto//OS Version 2.1, a particular exogenous ketone product.(22)

In an interview with Dave Asprey, ketone experts Dominic D’Agostino, Ph.D. argued ketone supplements could create the same blood ketone levels in as little as 10 –15 minutes rather than days.(23)

A few studies verify exogenous ketones’ benefits. Among Alzheimer’s disease-simulated mouse models, researchers found exogenous ketones showed improvement in plaque formation, inflammation, and brain damage, showing promise for people in the beginning stages of Alzheimer’s disease.(24) Another found exogenous ketones could “increase muscle efficiency with more dietary leniency” among athletes.(25)

I say supposedly because I’m not convinced exogenous ketones create supercharged, superfast ketosis like these supplements often claim.

Dietary leniency becomes an interesting term because exogenous ketone supplements suggest you could (theoretically) eat a cheeseburger with the bun and fries and get into ketosis. That’s right — putting you into ketosis without the work.

Even if exogenous ketones do work, there are drawbacks. Exogenous supplements – as ketone salts or esters – are made in a lab, not your body. Unlike ketones your liver produces, they don’t require any energy (calories) to create; in fact, you’re adding empty calories when you use these supplements.

They’re also expensive, taste terrible, and might still create the same unpleasant side effects MCT oil create. “Have you ever wanted to crap your pants? This is the product for you,” writes one Amazon reviewer and Verified Purchase of Keto//OS Version 2.1.

As with everything, your mileage will vary. If you’ve got the money sitting around – we’re talking about $150 for a 30-day supply – and want to see whether they work, go for it.

Instant-ketosis supplements make an interesting point: Permanent ketosis isn’t a destination or reality for most people. Even the most hardcore devotees occasionally “break” ketosis, which is probably a good idea if you hit a plateau or otherwise want to reset your body.

If full-time keto doesn’t sound appealing, you’ve got other options including cyclical ketosis, which puts your body into ketosis during certain times of the (but not the entire) day. (Personally, I think this is more reflective of our ancestral heritage and how the body would operate in nature.)

Bulletproof coffee, which its founder Dave Asprey calls a “kind of mild ketosis you can bring on by hacking your morning coffee,”(26) has become the most popular way to do that.

“Depending on your metabolism, just one large cup of Bulletproof Coffee in the morning (without other foods) can raise blood ketone levels to levels that suppress appetite,” writes Dave Asprey. “At my buddy Zak’s house last year, I ate a lot of sushi with rice for dinner which ended my ketosis because I woke up with blood ketone levels of 0.1 mM, far below the appetite suppression levels in these studies. Then Zak handed me a large fresh-made Bulletproof Coffee. A half hour later, my blood ketone meter read 0.7 mM – more than enough to kick ass all day.”(26)

In other words, like exogenous ketones, drinking Bulletproof provides a little – or a lot of –  leeway. You can literally – hypothetically – have your cake and eat it. Maybe.

Is Ketosis Overrated?

Despite that devotees sometimes speak in hushed tones about its benefits, not everyone has hopped on the keto train, and mainstream media loves to bash this diet’s potential drawbacks.

“When I experimented with the ketogenic diet, I felt incredibly cranky as well, and obsessed about foods I wasn’t supposed to eat—like black beans, bananas, and sweet potatoes,” writes Cynthia Sass, MPH, RD on  “That never happens when I have them in moderation. I also didn’t feel good about the fact that cutting those foods meant missing out on the vitamins, minerals, antioxidants, fiber, and prebiotics they provide.”(27)

In all fairness, I should mention four things with Sass’s comments:

  1. Not everyone can have certain foods (especially sweet ones) in moderation. For some people, a few bites of pie become the whole pie (or three).
  2. If you’re “obsessed” about certain foods, you might have food intolerances or an unhealthy relationship with that food. Just saying.
  3. Nearly any diet can create nutrient deficiencies you can avoid when you plan properly and take a good multivitamin-mineral.
  4. Crankiness is likewise normal as you adjust to any new eating plan. (And some people are just cranky period; blaming their diet is a copout.)

But when they’re transparent, even adherents aren’t always optimistic about ketogenic diets and acknowledge its potential drawbacks.

“[K]etosis is not all rainbows and unicorns,” writes Ben Greenfield, trainer and author of the New York Times Bestseller Beyond Training, who hitherto delivers an absolutely glowing review about keto. “There is definitely a dark side to ketosis.”

Among those obstacles, he mentions high triglycerides, increased inflammation via HS-CRP levels (a primary marker of inflammation), thyroid issues, and – the worst – social limitations.(28)

Earlier I mentioned adverse lipid effects, which studies show eventually normalize but can be very alarming when your doctor tells you that, say, your triglycerides have soared since your last visit.

Social limitations can also make doing or sticking with ketogenic diets a challenge. Never mind clear-the-room bad breath; family dinners might suddenly become a challenge, you can’t join your friends for ice cream or beer, and you might get awkward glances when you ask for extra butter for your steak at a restaurant (as some keto devotees do).

Two bigger issues with a ketogenic diet are its sustainability and its deviation from real food. While coconut oil is a healthy fat source, MCT oil is heavily processed.

Kris Gunnars has three excellent points about “Why Bulletproof Coffee is a Bad Idea”(29):

  1. You’re displacing a potentially high-nutrient meal with a low-nutrient coffee drink (butter has a few nutrients, but MCT is basically empty calories)
  2. Saturated fat can be healthy, but we didn’t evolve eating such massive amounts (that criticism could double for ketogenic diets themselves)
  3. Bulletproof coffee could elevate your cholesterol levels (including advanced risk factors like ApoB and LDL particle numbers) to dangerous levels

In all fairness, Bulletproof does not claim to be a ketogenic diet.

“It does utilize intermittent, cyclical ketosis but discourages long-term ketosis for everyone due to a number of factors including thyroid or hormone imbalance, adrenal fatigue, poor sleep quality, and extremely dry eyes, to name a few,” says Dave Asprey. “It’s also clear that for some people, permanent ketosis is not optimal.”(30)

Still, putting butter and a heavily processed oil into your morning coffee adds a ton of calories without many nutrients. This isn’t the stuff your Paleolithic ancestors ate, and your great-grandparents would likely have given you a “You’re putting WHAT in your coffee!!??” look. Popular though it is, Bulletproof Coffee is far, far removed from real food.

Many (but not all) people do well on a ketogenic diet on the short term but find sustaining it for months or years to be a challenge, even when they cycle keto and non-keto days. (That can be a slippery slope in itself…)

Others find non-keto friendly foods start slipping back into their diets (AKA they start adding their old favorites in) and regain weight. One friend told me she became overly obsessed with being in ketosis, running to the bathroom every hour to check her urine levels with ketone strips.

Symptoms like nausea, vomiting, and “running to the bathroom” – collectively called “keto flu” – are common, especially during the earlier days when your body adjusts to this alternative fuel source. Most people eventually adapt, but those first few weeks can be hard.

Simply put, getting into ketosis can be a challenge, and staying there long term (months or years) presents a different challenge with sustainability. Then there’s all that dietary fat, which even the most disciplined devotee can grow tired of.

One review of 229 hunter-gatherer communities found a dietary fat intake of 28-58 percent,(31) accounting for food variations. In other words, some groups ate more tubers, fruits, and other carbs, while others ate higher-fat animal foods.

Regardless, nobody in those communities hit anywhere near the 80 – 90 percent fat amounts a traditional ketogenic diet demands.

I don’t believe our bodies were designed to process that amount of fat at once. It’s not a diet you would experience in nature; it’s totally forced. If you do a ketogenic diet, I strongly suggest using a high-lipase digestive enzyme to break down all that fat. Otherwise, you’ll probably feel nauseous, “heavy,” or otherwise less than stellar.

Even then, keto isn’t for everyone, including people who do high-intensity interval training (HIIT).

One study looked at a long-term polyunsaturated fatty acid-rich ketogenic diet on aerobic performance and exercise metabolism in off-road cyclists. While they found some favorable effects, researchers concluded ketogenic diets decrease the ability to perform high intensity work, due to decreased glycogen muscle stores.(32) No two athletes are the same, but this type of information should not be ignored!

That makes sense when you consider while your body can utilize ketones as primary fuel during long-distance (endurance) workouts, your muscles prefer glucose during high-intensity training. During short, intense activity bursts your muscles work anaerobically (without oxygen). Ketones can’t be broken down without oxygen, so during high-intensity training your muscles can’t utilize them as fuel.

Like any diet, ketosis isn’t perfect, nor is it right for everyone. While it can help you lose weight – though it may not, and it wasn’t designed for weight loss – you don’t need to be in ketosis to lose weight, and it could make you gain weight.

“Ketosis is not necessary for weight loss,” writes Bowden. “You could be in ketosis and not lose weight, just as you could lose weight without being in ketosis. You won’t burn your stored fat (and the ketone bodies made from it) if you have a surplus of fuel coming into the pipeline from the food you’re eating. If you’re eating 10,000 calories of fat and no carbs, you’ll definitely be producing a ton of ketones but you won’t lose a pound.”

That doesn’t mean you can’t flirt with ketosis, such as my Advanced Plan that includes 40 – 60 percent dietary fat — and probably much closer to ancestral intakes of fat. It’s still a high-fat diet that could help you “flirt” with without going full-on keto. On this plan, you’ll focus on healthy fat sources like wild-caught fish, grass-fed beef, avocado, coconut, nuts, and seeds.

These and other healthy fats edge out empty-calorie carbohydrates. Add before you take away: Rather than go strictly low-carbohydrate, add more good fat sources and you’ll automatically shift your macros to a lower-carbohydrate diet.

Rather than the 80 – 90 percent fat diet traditional ketogenic diets implement, I would recommend about a 55-percent fat diet. That’s still pretty high-fat, and you’ll be getting BHB and overall keto benefits if you keep your carb count relatively low (say, under 50 grams a day).

Here’s an easier plan: Stop obsessing over numbers, period, Just eat real food with an emphasis on healthy fat.

Even then, you need to be mindful about calories. While dietary fat is incredibly satiating, it carries more calories per gram than carbohydrate or protein. As Bowden says, overdoing fat – even healthy fats – can put you in ketosis, but that doesn’t mean you’ll lose weight.

I’m not completely opposed to taking exogenous ketones. To jumpstart your metabolism, they might work temporarily, but should never be a ketogenic “mainstay.” Like I’ve said with respect to just about every exogenous vitamin (even Vitamin C): Ideally, you should strive to get the nutrients you need from food. Any supplement used to “force” some type of physiological change in the body is essentially being used like a drug. The word “supplement” originally came from the premise of supporting the body with nutrients it might be missing from an already-healthy diet.

You might do glowingly on a higher-fat diet. You might find a ketogenic diet is your sweet spot (no pun intended) to lose weight, reverse diabetes or other chronic illnesses, and look and feel your best.

Or you might not. You might crave certain foods, lag in energy, sleep terribly, snap at a significant other and coworkers, and eventually nose-dive into a pint of butter pecan.

Even if ketosis does work for you, cyclical keto (rather than “staying” in ketosis supercharged with exogenous ketones) seems to work best for most people. Ketogenic diets were never intended to be a permanent destination, and with the potential leeway of cyclical keto, why would you want to?

Whatever you decide, that’s the beauty of biochemical individuality: One size most definitely does not fit all, and that goes quadruple for diet plans.

If you’ve ever done a ketogenic diet, have you experience these or other drawbacks? Did you find the diet hard to stick with longer term? Share your thoughts in the comments below or on my Facebook page.

Is There a Dark Side of Ketosis?

Dr. B.J. Hardick

About Dr. B.J. Hardick

Dr. B.J. Hardick is a Doctor of Chiropractic and internationally-recognized natural health author and speaker. His health journey began as a child — alternative medicine is the only medicine he has ever known. In 2009, he authored his first book, Maximized Living Nutrition Plans. In 2018, he authored his second book, Align Your Health. An energizing and passionate speaker, Dr. Hardick shares his lifestyle methods to numerous professional and public audiences every year in the United States and Canada. His teachings encompass the principles of ancestral nutrition, detoxification, functional fitness, mindfulness, and green living. Learn More