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How Keto Affects the Brain

This entry is part 3 of 4 in the series Keto Basics

Apart from the well-documented benefits ketogenic diets provide—like weight loss1, lower blood sugar and blood pressure2, and improved cardiovascular risk factors3—people commonly report sharper thinking. Brain fog disappears, and it’s smooth sailing for cognitive function. Is this—no pun intended—all in people’s heads, or is keto genuinely good for the brain?

Your Brain on Glucose & Insulin

There isn’t much published scientific research specifically studying the effects of ketogenic diets on brain function in healthy humans outside the epilepsy world, so we can’t say for certain that keto is “good” for the brain. However, we do have a pretty good idea of what’s not good for the brain: chronically high blood sugar and insulin.

Type 2 diabetes and high blood pressure—two conditions rooted in high blood sugar and/or insulin—are among the risk factors for Alzheimer’s disease (AD). In fact, researchers now regularly call AD “type 3 diabetes,” and you might also come across the term “brain insulin resistance.”4,5 The links between metabolic syndrome (driven by chronically elevated insulin) and cognitive impairment are so strong that researchers also use the phrase “metabolic-cognitive syndrome.”6

The reason AD is called “type 3 diabetes” is that the primary problem in the brain of someone with AD is that neurons in affected regions of the brain are no longer metabolizing glucose properly—that is, they cannot convert glucose into energy, so they’re basically starving for fuel. Calling AD “a brain form of diabetes”4 is helpful because it immediately makes a connection to problems with glucose, but it misses what might be an even more important factor in this energy shortage in the brain: chronically high insulin.

Millions of people have normal blood glucose (a.k.a. blood sugar) levels, but very high insulin, and having chronically high insulin—even when blood sugar is normal—is a major risk factor for AD. This is independent of family history or genetics: if you have high insulin most of the time, you have an increased risk for developing AD. According to one study, compared to people with normal insulin levels, those who had high insulin but who were not diabetic had double the risk of developing AD.7

What about when your blood sugar is just a little bit higher than normal? What if it’s slightly elevated but not so high that you’ve been diagnosed with diabetes? Here we also see some frightening data. One paper said it pretty clearly: “… even in the absence of manifest type 2 diabetes mellitus or impaired glucose tolerance, chronically higher blood glucose levels exert a negative influence on cognition, possibly mediated by structural changes in learning-relevant brain areas.”8 In plain English: people with higher blood glucose had worse cognition than people with lower glucose, and this was probably due to changes in the physical structure of the brain. This echoed earlier research which had similar findings—elevated average blood glucose may be a risk for dementia even at levels lower than the diabetic range.9

Alzheimer’s is only the most severe manifestation of the adverse effects of chronically high blood sugar and insulin on the brain. What about when things are in a much milder state? Could this be what we casually call brain fog? When your blood sugar fluctuates wildly throughout the day, it’ll reach some big highs and drop to some precipitous lows. Nervousness, anxiety, confusion, and difficulty speaking are some of the brain-related effects of acute hypoglycemia (low blood sugar).10

So if chronically high blood sugar has a negative influence on cognition11, then it’s possible that keeping blood sugar within a healthy range could have a protective influence. We can’t say this for certain, but it’s a pretty safe bet that you’re better off having normal levels of blood sugar and insulin compared to chronically high levels of either.

Fueling the Brain

Well-meaning friends and family who tried to steer you away from keto may have peppered you with arguments about the brain “needing carbs,” or perhaps a medical or nutrition professional even warned you that your brain would starve on a low-carb diet because the brain needs 120 grams of glucose every day. Let’s set the record straight on this.

It’s true that your brain needs glucose. There’s no denying that. But a need for glucose doesn’t equate to a need for lots of sweet and starchy carbohydrates in your diet—or any carbs, for that matter. The human body is the ultimate reuse and recycle machine. It’s great at converting things into other things—moving and changing things here and there like some kind of wondrous biochemical Jenga game or Rubik’s cube. (Remember those?!) One of the things your body is great at making out of many different raw materials is glucose. You can make glucose from amino acids (from protein), glycerol (from fats), and from a few other starting points—no bagels, pasta, bread, rice, or cookies required!

One thing is clear: the brain is an energy hog. Sources differ, but as a general ballpark, your brain represents only about 2% of your body weight, but it sucks up nearly 20% of your body’s energy.12 But does all this energy have to come from glucose, or can the brain use some other fuel instead?

According to researchers, the brain metabolizes about 120 grams of glucose per day “under conditions of normal glucose availability.”12 But what about under other conditions? What about in someone eating a very low-carb or ketogenic diet?

Well, as I mentioned, your body can make all the glucose it needs in-house. If your brain absolutely required a certain amount of glucose every day and your body couldn’t supply it, no one would ever survive more than a day or two of fasting. So either your body has no problem generating 120 grams of glucose in the total absence of dietary carbohydrate, or maybe your brain doesn’t need quite that much glucose if it’s being fueled by something else.

In addition to being great at recycling, your body—and brain—are like hybrid cars. They adapt to running on whatever fuel you give them. Most cells in your body can use glucose, fats, or ketones. Your brain can use glucose and just a small amount of fat, but it’s a champ at using ketones. Look at this breakdown of how much of your brain’s energy supply comes from ketones at different blood levels of beta-hydroxybutyrate (βOHB).

Blood ketone level
Proportion of Brain
Energy Supplied
0.3–0.5 mM3–5%
1.5 mM18%
5 mM60%
7 mM>60%

Data from reference 12.

Even people not on ketogenic diets could achieve a blood ketone level of 0.3–0.5 mM or higher if they do a hard workout and it’s been a few hours since their last meal. 1.5 mM is easily achievable when carbs are very low. The higher numbers in this table would likely only be seen in someone doing an extended fast, but levels in between—2.0–4.0 mM, for example—could provide a substantial amount of fuel for the brain and are not unheard of in people doing strict ketogenic diets.

Is it essential to be in ketosis, then? No. A few billion people all over the world who have a healthy cognitive function but who are not on ketogenic diets show us this implicitly. But based on the research we explored earlier, what probably is needed for healthy cognition throughout life is maintaining healthy blood sugar and insulin levels. Keto is certainly one way to do that, but everyone’s carb tolerance varies. Some people will have to stay ultra-low-carb most of the time; others can be more generous.

Exciting Research in Alzheimer’s and Traumatic Brain Injury

Getting back to the association between diabetes, metabolic syndrome (MetSyn), and cognitive impairment, some small-scale research suggests that ketogenic diets and other lifestyle interventions that help correct MetSyn may also improve cognitive function. Ketogenic diets combined with exercise, intermittent fasting, or brain training games were shown to reverse mild cognitive impairment (MCI, the precursor to Alzheimer’s) in three subjects, one with type 2 diabetes and two with MetSyn.13,14,15 The diabetes and MetSyn were also greatly improved, and while we can’t say for certain that those improvements caused the reversal of cognitive impairment, it’s a plausible hypothesis.

Most of the research looking at ketones as an alternative brain fuel to glucose in Alzheimer’s disease have used exogenous ketones or MCT oil rather than ketogenic diets. This is disappointing but understandable. It can be difficult even for young, healthy, able-bodied people to adhere to strict ketogenic diets. Now imagine someone with cognitive impairment, who might also have limited mobility and capacity to cook. Caregivers already face heavy burdens in looking after their loved ones; trying to force them to make dietary changes they’re opposed to only makes things harder. Plus, by using exogenous ketones or MCT oil without changing someone’s diet, researchers narrow down confounding issues that might cloud the results. If a subject’s cognition improves when their ketone levels are elevated from MCT oil or exogenous ketones, then it’s more likely that it’s a direct result of the ketones and not something else, like weight loss, better blood sugar control, less inflammation, or other things we know keto typically leads to.

Elevated ketones, by themselves, aren’t a slam dunk for radically improving Alzheimer’s or cognitive impairment. But let’s not dismiss even minor beneficial effects, especially considering that right now, there are no effective treatments for AD. Generally speaking, these studies show that at least some people have improved cognition when their ketone levels are elevated.16-19 In MCI, the brain energy deficit is specific to glucose, and “at least partially correcting this deficit with ketones results in cognitive improvements.”16

Ketogenic diets and exogenous ketones also show potential in improving recovery from traumatic brain injury (TBI). Almost all the research in this area has been done in animals, but it’s encouraging and holds promise for people affected by these devastating injuries. TBI and AD have a surprising amount of overlap, first and foremost, a reduced capacity of the brain to convert glucose into energy.20-22 TBI also results in increased free radicals, mitochondrial damage, an increased need for antioxidants, increased susceptibility to neuronal death, and other issues that ketones themselves or the collective effects of ketogenic diets can address.23

Using ketogenic diets or exogenous ketones as therapy in TBI is in its infancy, but one thing that has been well known for a while is that higher blood sugar is associated with worse outcomes in TBI patients. So why not adopt a nutritional strategy that keeps blood sugar in a healthy range and gives neurons an alternative fuel to glucose? Research in animals and humans suggests that a switch to a ketogenic state might help to protect damaged neurons.20,24

Spotlight on Vitamin B12 and Choline

Vitamin B12 is a crucial factor for anyone concerned about brain health and cognitive function. Outright B12 deficiency and milder subclinical insufficiency are common, particularly among older people who may be consuming fewer foods rich in B12, and whose digestive capacity may be waning, making them less able to absorb B12 from the foods they do consume. Inadequacy of this critical nutrient comes with a long list of signs and symptoms, including confusion, memory loss, dementia, dizziness, altered mental status, depression, apathy, paranoia, mania, delusions, psychosis, and hallucinations.25 So yes, it’s fair to say that suboptimal B12 status could have a major impact on the brain.

With this in mind, it’s possible that raising B12 levels is another way keto may be beneficial for the brain, entirely separate from its influence on blood glucose, insulin, and ketones. An omnivorous ketogenic diet that includes red meat, eggs, pork, seafood or shellfish, provides plenty of B12. People may have been eating these foods all along, even before keto, but when sugary and starchy carbs are off the menu, replaced by fats and proteins, it’s possible people get more B12 than they did before.

Consuming foods rich in B12 doesn’t guarantee your blood levels will increase or be maintained at healthy levels, though. As we mentioned in a previous article, eating certain foods doesn’t automatically mean you’ll digest them effectively and absorb the nutrients they contain. So if you know you have compromised digestive function, consider getting your B12 level checked (it’s a simple blood test), and take supplements if warranted. B12 is found only in foods from the animal kingdom, so lacto-ovo vegetarians can get B12 from eggs and dairy products, but strict vegans must supplement.

Choline is another nutrient critical for brain health and neurological function. It’s an essential part of all cell membranes, and is a precursor to acetylcholine, a neurotransmitter that affects “memory, mood, muscle control, and other brain and nervous system functions.”26 Patients with Alzheimer’s may have lower levels of acetylcholine compared to healthy people, and one class of drugs used to treat AD is designed to reduce the breakdown of this critical compound.27

Your body synthesizes choline, but only in small amounts—not enough to meet the full demands, so you need to get some from your diet. Some of the richest sources of choline are the foods commonly consumed on ketogenic diets: eggs, red meat, pork, seafood, plus nuts and seeds, broccoli, and Brussels sprouts. Plant foods contain choline, but animal foods are more concentrated sources. To the extent that increased dietary choline may be providing more raw material for acetylcholine, this might be another way low-carb or ketogenic diets may be beneficial for the brain.


Ketogenic diets are impressive for helping people lose weight, banish acid reflux28, reverse non-alcoholic fatty liver29, improve hormone balance in PCOS30,31, and for many other health issues. It stands to reason that this very low-carb way of eating would also be beneficial for the brain. So if you’re doing keto and you’ve noticed improved mental clarity and cognitive sharpness, it is in your head—and in the rest of your body, too.

Wondering how keto affects mental health? Stay tuned. We’ll cover that in a future article.


  1. Staverosky T. Ketogenic Weight Loss: The Lowering of Insulin Levels Is the Sleeping Giant in Patient Care. J Med Pract Manage. 2016;32(1):63-66.
  2. Westman EC, Tondt J, Maguire E, Yancy WS Jr. Implementing a low-carbohydrate, ketogenic diet to manage type 2 diabetes mellitus. Expert Rev Endocrinol Metab. 2018;13(5):263-272. doi:10.1080/17446651.2018.1523713.
  3. Bhanpuri NH, Hallberg SJ, Williams PT, et al. Cardiovascular disease risk factor responses to a type 2 diabetes care model including nutritional ketosis induced by sustained carbohydrate restriction at 1 year: an open label, non-randomized, controlled study. Cardiovasc Diabetol. 2018;17(1):56. doi:10.1186/s12933-018-0698-8.
  4. de la Monte SM. The Full Spectrum of Alzheimer’s Disease Is Rooted in Metabolic Derangements That Drive Type 3 Diabetes. Adv Exp Med Biol. 2019;1128:45-83. doi:10.1007/978-981-13-3540-2_4.
  5. Frazier HN, Ghoweri AO, Anderson KL, Lin RL, Porter NM, Thibault O. Broadening the definition of brain insulin resistance in aging and Alzheimer’s disease. Exp Neurol. 2019;313:79-87. doi:10.1016/j.expneurol.2018.12.007.
  6. Frisardi V, Solfrizzi V, Seripa D, et al. Metabolic-cognitive syndrome: a cross-talk between metabolic syndrome and Alzheimer’s disease. Ageing Res Rev. 2010;9(4):399-417. doi:10.1016/j.arr.2010.04.007.
  7. Luchsinger JA, Tang MX, Shea S, Mayeux R. Hyperinsulinemia and risk of Alzheimer disease. Neurology. 2004;63(7):1187-1192. doi:10.1212/01.wnl.0000140292.04932.87.
  8. Kerti L, Witte AV, Winkler A, Grittner U, Rujescu D, Flöel A. Higher glucose levels associated with lower memory and reduced hippocampal microstructure. Neurology. 2013;81(20):1746-1752. doi:10.1212/
  9. Crane PK, Walker R, Hubbard RA, et al. Glucose levels and risk of dementia. N Engl J Med. 2013;369(6):540-548. doi:10.1056/NEJMoa1215740.
  10. Mayo Clinic. Diabetic Coma. Accessed Aug 31, 2020 from
  11. Saedi E, Gheini MR, Faiz F, Arami MA. Diabetes mellitus and cognitive impairments. World J Diabetes. 2016;7(17):412-422. doi:10.4239/wjd.v7.i17.412.
  12. Hashim SA, VanItallie TB. Ketone body therapy: from the ketogenic diet to the oral administration of ketone ester. J Lipid Res. 2014;55(9):1818-1826. doi:10.1194/jlr.R046599.
  13. Stoykovich S, Gibas K. APOE ε4, the door to insulin-resistant dyslipidemia and brain fog? A case study. Alzheimers Dement (Amst). 2019;11:264-269. doi:10.1016/j.dadm.2019.01.009.
  14. Dahlgren K, Gibas KJ. Ketogenic diet, high intensity interval training (HIIT) and memory training in the treatment of mild cognitive impairment: A case study. Diabetes Metab Syndr. 2018;12(5):819-822. doi:10.1016/j.dsx.2018.04.031.
  15. Brown D, Gibas KJ. Metabolic syndrome marks early risk for cognitive decline with APOE4 gene variation: A case study. Diabetes Metab Syndr. 2018;12(5):823-827. doi:10.1016/j.dsx.2018.04.030.
  16. Croteau E et al. A cross-sectional comparison of brain glucose and ketone metabolism in cognitively healthy older adults, mild cognitive impairment and early Alzheimer’s disease. Exp Gerontol. 2018 Jul 1;107:18-26.
  17. Fortier M, Castellano CA, Croteau E et al. A ketogenic drink improves brain energy and some measures of cognition in mild cognitive impairment. Alzheimers Dement. 2019 May;15(5):625-634.
  18. Cunnane SC, Courchesne-Loyer A, Vandenberghe C, et al. Can Ketones Help Rescue Brain Fuel Supply in Later Life? Implications for Cognitive Health during Aging and the Treatment of Alzheimer’s Disease. Front Mol Neurosci. 2016;9:53. doi:10.3389/fnmol.2016.00053.
  19. Cunnane SC, Courchesne-Loyer A, St-Pierre V, et al. Can ketones compensate for deteriorating brain glucose uptake during aging? Implications for the risk and treatment of Alzheimer’s disease. Ann N Y Acad Sci. 2016;1367(1):12-20. doi:10.1111/nyas.12999.
  20. Prins M. Diet, ketones, and neurotrauma. Epilepsia. 2008;49 Suppl 8(Suppl 8):111-113. doi:10.1111/j.1528-1167.2008.01852.x
  21. Bernini A, Masoodi M, Solari D, et al. Modulation of cerebral ketone metabolism following traumatic brain injury in humans. J Cereb Blood Flow Metab. 2020;40(1):177-186. doi:10.1177/0271678X18808947.
  22. Prins ML, Matsumoto JH. The collective therapeutic potential of cerebral ketone metabolism in traumatic brain injury. J Lipid Res. 2014;55(12):2450-2457. doi:10.1194/jlr.R046706.
  23. Greco T, Glenn TC, Hovda DA, Prins ML. Ketogenic diet decreases oxidative stress and improves mitochondrial respiratory complex activity. J Cereb Blood Flow Metab. 2016;36(9):1603-1613. doi:10.1177/0271678X15610584.
  24. Miller VJ, Villamena FA, Volek JS. Nutritional Ketosis and Mitohormesis: Potential Implications for Mitochondrial Function and Human Health. J Nutr Metab. 2018;2018:5157645. doi:10.1155/2018/5157645.
  25. Pacholok, S and Stuart J. Could It Be B12? An Epidemic of Misdiagnoses. Quill Driver Books, Linden Publishing, Inc. Fresno, CA, 2011.
  26. S. Department of Health and Human Services. National Institutes of Health, Office of Dietary Supplements. Choline Fact Sheet for Health Professionals. Updated July 2020. Accessed Aug 31, 2020 from
  27. Oregon State University. Linus Pauling Institute Micronutrient Information Center. Choline. Updated Jan 2015, accessed Aug 31, 2020 from
  28. Pointer SD, Rickstrew J, Slaughter JC, Vaezi MF, Silver HJ. Dietary carbohydrate intake, insulin resistance and gastro-oesophageal reflux disease: a pilot study in European- and African-American obese women. Aliment Pharmacol Ther. 2016;44(9):976-988. doi:10.1111/apt.13784.
  29. Luukkonen PK, Dufour S, Lyu K, et al. Effect of a ketogenic diet on hepatic steatosis and hepatic mitochondrial metabolism in nonalcoholic fatty liver disease. Proc Natl Acad Sci U S A. 2020;117(13):7347-7354. doi:10.1073/pnas.1922344117.
  30. Mavropoulos JC, Yancy WS, Hepburn J, Westman EC. The effects of a low-carbohydrate, ketogenic diet on the polycystic ovary syndrome: a pilot study. Nutr Metab (Lond). 2005;2:35. doi:10.1186/1743-7075-2-35.
  31. Paoli A, Mancin L, Giacona MC, Bianco A, Caprio M. Effects of a ketogenic diet in overweight women with polycystic ovary syndrome. J Transl Med. 2020;18(1):104. doi:10.1186/s12967-020-02277-0.


Is Keto Dairy Free?

This entry is part 2 of 4 in the series Keto Basics

Look at pictures of food on keto social media and no one could blame you for thinking that dairy is required when you’re eating this way. Bowls are filled with cheese covered in rivers of melted cheese, with cheese sprinkled on top for good measure. People put butter in their coffee, and keto dessert cookbooks would be pretty empty if you took out all the recipes calling for cream cheese and heavy cream. But what if you’re allergic or sensitive to dairy, or you just plain don’t like the stuff? Is it possible to do dairy-free keto?

What Makes Keto Ketogenic?

Can you do dairy-free keto Yes! Ketogenic diets have more to do with what you don’t eat than what you do eat. Diets are ketogenic not based on what they include, but rather, on what they exclude. Don’t eat sugar or starch. Beyond that, what you choose to consume is up to you. The single most important thing about keto is keeping your carb intake low. Period. There are no specific foods that you need to include to make your diet “more keto” or to make it work better.

Based again on those alluring food pics, it would be easy to think that you have to eat bacon, or ribeye steak, coconut oil, almond flour cookies, or cauliflower rice to belong to the keto club. But that’s not how it works. The beauty of keto is that it’s entirely customizable. Keep your carbs very low, and get your protein and fat from whichever foods you like. Dairy certainly fits in well, but it’s not required.

Keto Without Dairy

Since keto is defined more by what’s not in your diet than by what is, you can definitely do keto without dairy—and many people do. Dairy has two main roles on ketogenic diets: first, it’s delicious, and second, it’s a great source of fat. But there’s a world of other foods that fulfill both those criteria, depending on your personal taste preferences. Guacamole, anyone? If you’re an avocado fan, you’ll have no problem getting plenty of good fats in your keto diet. Coconut more your thing? Coconut milk, coconut oil, and coconut butter provide flavor along with a big dose of healthy fat. And of course, there’s lard, tallow, schmaltz, and other traditional animal fats.

Dairy is also a protein source—one that plays a big role in lacto- or lacto-ovo-vegetarian keto diets. Meat eaters don’t have to worry about getting enough protein on keto, but those who avoid animal products except eggs and dairy might need to be a bit more careful. Cottage cheese, Greek yogurt, and whey protein shakes are all low-carb sources of protein. (Yes, cottage cheese and Greek yogurt. These might not work if you need to stay ultra-strict keto for medical reasons, but everyone’s carb threshold differs. Some people can have more carbs than others and still stay in a ketogenic state.)

But what if dairy is off-limits? If you need to avoid dairy but you’re not a vegetarian, the rest of the protein world is still open to you: beef, pork, lamb, chicken, turkey, seafood, venison, duck … there’s no shortage of protein options. If you choose to avoid these animal foods, however, getting adequate protein will be a bit tougher. If eggs are on your menu, eat them liberally. They’re phenomenal sources of protein, fat, and micronutrients.

If you’re a dairy-free vegetarian, then beyond eggs, you can use vegetarian protein sources, like pea, hemp, or rice proteins. (Always read labels and look at the carb counts. Most protein powders are low in carbs, but never assume.) If your diet can be slightly more liberal with regard to carbs, you may be able to incorporate tofu, lentils, and other lower-carb beans and pulses as protein sources. Not everyone needs to be in ketosis all the time to reap the benefits of lower-carb eating.

After all this talk about doing keto without dairy, it’s worth pointing out that some people with lactose intolerance do well-eating dairy foods that are very low in lactose, like butter, ghee, or long-aged cheeses, all of which are perfect for keto. The longer a dairy product has been aged or fermented, the more lactose the culturing bacteria consume, and the less remaining in the final product. So if you have lactose intolerance but love dairy, stick to dairy foods that are almost all fat (butter, ghee, heavy cream), and those that have been aged for a long period of time.

Does Dairy Affect Insulin?

Whether to include dairy in your diet is a personal decision. It may be true that, technically, milk is the only food specifically intended to help small mammals grow larger, and that this could potentially be a problem if you’re specifically looking to lose weight. It’s also true that dairy stimulates insulin and a similar hormone, insulin-like growth factor 1 (IGF-1)1,2,3, but neither of these means that including dairy foods in a ketogenic or low-carb diet is harmful.

A small effect on these hormones in the context of a very low-carb diet is likely different from the effect that results when dairy is included in the diet of someone with chronically high blood sugar or insulin. It must be noted that most research connecting dairy consumption to chronic cardio-metabolic disease is epidemiological in nature (meaning it can’t establish cause-and-effect), and has been conducted in populations consuming mixed—i.e. high-carb—diets. Very little research has been done investigating dairy specifically in the context of ketogenic diets.

Some people notice that dairy foods (particularly cow dairy) cause or exacerbate acne. Research looking at the evidence for the acne-promoting effects of milk and other dairy products known to stimulate insulin concluded that “restriction of milk consumption or generation of less insulinotropic milk will have an enormous impact on the prevention of epidemic western diseases like obesity, diabetes mellitus, cancer, neurodegenerative diseases, and acne.”4

The key here is to limit the consumption of fluid milk and other dairy foods that stimulate insulin more than items that are very low in carbs, like butter and cream. The work of nutrition research pioneer Weston A. Price tells us that many populations whose diets included liberal amounts of dairy foods were healthy, robust, long-lived, and free of the chronic diseases that plague us now. So it’s not dairy, per se, that’s driving these modern illnesses. It’s more likely dairy in the context of a diet that already over-stimulates insulin.5 Including cheese, butter, ghee, cream, sour cream or cream cheese in a very low-carb diet is likely fine—the evidence being many thousands of people who are doing exactly this, and whose health has improved dramatically just by cutting carbs.

A 2019 review presented evidence that consuming full-fat and fermented dairy is not associated with increased risk for cardiovascular disease or type 2 diabetes.6 Earlier research noted, “Data from RCTs [randomized controlled trials] suggest that dairy consumption has no impact on insulin resistance and glucose and insulin homeostasis in the short term, but may be beneficial in the long term.”7 (Emphasis added.) So if you’ve been including dairy regularly on your keto diet and you’re happy with your health, body size, and skin appearance, keep calm and dairy on.

Bottom Line

Do what works for you. Dairy can be a delicious and convenient part of ketogenic diets, but it’s not required. Your results won’t be compromised if you skip the butter and cheese and get your fat from meats and seafood, olive oil, avocado, nuts and seeds, and other sources. If you’re doing dairy-free keto and could use some recipe inspiration, the book Dairy-Free Keto Cooking can help breathe new life into your kitchen routine.


  1. Melnik BC, Schmitz G. Role of insulin, insulin-like growth factor-1, hyperglycaemic food and milk consumption in the pathogenesis of acne vulgaris. Exp Dermatol. 2009;18(10):833-841. doi:10.1111/j.1600-0625.2009.00924.x.
  2. Melnik BC, John SM, Schmitz G. Over-stimulation of insulin/IGF-1 signaling by western diet may promote diseases of civilization: lessons learnt from laron syndrome. Nutr Metab (Lond). 2011;8:41. doi:10.1186/1743-7075-8-41
  3. Clatici VG, Voicu C, Voaides C, Roseanu A, Icriverzi M, Jurcoane S. Diseases of Civilization – Cancer, Diabetes, Obesity and Acne – the Implication of Milk, IGF-1 and mTORC1. Maedica (Buchar). 2018;13(4):273-281. doi:10.26574/maedica.2018.13.4.273.
  4. Melnik BC. Evidence for acne-promoting effects of milk and other insulinotropic dairy products. Nestle Nutr Workshop Ser Pediatr Program. 2011;67:131-145. doi:10.1159/000325580.
  5. Cordain L, Eades MR, Eades MD. Hyperinsulinemic diseases of civilization: more than just Syndrome X. Comp Biochem Physiol A Mol Integr Physiol. 2003;136(1):95-112. doi:10.1016/s1095-6433(03)00011-4.
  6. Astrup A, Geiker NRW, Magkos F. Effects of Full-Fat and Fermented Dairy Products on Cardiometabolic Disease: Food Is More Than the Sum of Its Parts. Adv Nutr. 2019;10(5):924S-930S. doi:10.1093/advances/nmz069.
  7. Drouin-Chartier JP, Côté JA, Labonté MÈ, et al. Comprehensive Review of the Impact of Dairy Foods and Dairy Fat on Cardiometabolic Risk. Adv Nutr. 2016;7(6):1041-1051. doi:10.3945/an.115.011619.
By |2020-09-01T09:35:40-06:00August 26th, 2020|Categories: Keto Basics|Tags: , , , , , |0 Comments

Can Keto Make You Tired?

This entry is part 1 of 4 in the series Keto Basics

“I can’t sit still!”

“I’m bursting with energy!”

“I don’t need an alarm to wake up anymore!”

Any of these sound familiar? Poke around keto-oriented social media and you’re bound to come across people claiming their energy is through the roof. That they started working out because they didn’t know what else to do with all that pent-up power. But what if you haven’t felt this magical energy boost? What if keto’s done the opposite for you and you feel sluggish? Can keto make you tired?

The answer to this is a definite no … and yes. Like most things when it comes to the complex and kooky human body, it depends. Fortunately, if you have found yourself dragging more than usual—physically or mentally and emotionally—it’s not keto, per se, that’s the cause, so you don’t have to abandon a diet that might be helping you lose weight1, improve PCOS2, get rid of acid reflux3, prevent migraines4, or massively improve type 2 diabetes5. What’s likely making you feel tired is the way keto affects other things in your diet and health picture.

Let’s take a look at why keto typically gives people more energy, and then address the reasons why you might have less energy than when you were eating more carbs—and most importantly, what to do about them.

Keto Usually Boosts Energy

After an initial dip during the adaptation phase, most people report an increase in energy levels when following a ketogenic diet. It’s not uncommon for formerly sedentary folks to become more active without having to force it—it happens naturally because they’re feeling more energetic. There’s no formal research published on this particular “side-effect” of keto, but it’s widely acknowledged among keto-oriented doctors and other health professionals, not to mention among patients, themselves.

What could be behind this well-noted, if anecdotal, energy boost? A couple of mechanisms potentially explain it. First, when your body’s adapted to running mostly on fat, you’re no longer subject to wild ups and downs in blood sugar—and those lows can leave you feeling sluggish, weak, or lightheaded.6 (It’s important to note, though, that very high blood sugar can also cause fatigue.) When you’re off the blood sugar rollercoaster, you have constant access to premium fuel in the form of fat and ketones. Molecule for molecule, at the cellular level, fats provide more energy than glucose does. (As ATP, the cellular “energy currency,” if you remember that from high school biology class!)

Second, ketones, themselves, may provide a bit of a lift—perhaps even just a perceived one. It has long been believed that “hitting the wall” during a grueling endurance event is a purely physical phenomenon, resulting from processes limited to the working muscles. But some researchers believe this breaking point or “bonking” may have more to do with the brain:

“Whereas prolonged intense exercise when one is dependent upon glucose/glycogen progressively depletes fuel reserves available to sustain the brain, the keto-adapted athlete may benefit from the opposite effect. As endurance exercise progresses, unlike the blood glucose concentration, the blood ketone concentration does not decline but tends to rise somewhat, ensuring a stable supply of fuels to the brain. Consistent with this improved cerebral fuel delivery, ultra-endurance athletes frequently report that mental clarity is maintained better during prolonged exercise in the keto-adapted state. This is in stark contrast to the problems of central fatigue and ‘hitting the wall’ that commonly occur in athletes who follow a high-carbohydrate fuelling strategy and to which a progressive hypoglycemia that develops during prolonged exercise may contribute to fatigue.”8

Okay, that’s great for endurance athletes, but what about we mere mortals, who aren’t regularly running marathons or doing triathlons? Well, apart from anecdotal reports of increased oomph from people following ketogenic diets, a study from 2019 showed that subjects with multiple sclerosis reported improvements in fatigue after three months of adhering to keto.9  So this way of eating appears to be beneficial even among people with severely compromised energy levels.

What If You Are Tired on Keto?

If keto hasn’t bestowed its energy blessing upon you, what gives? What might be getting in the way, and what can you do about it?

  1. Not enough sodium.

Ketogenic diets increase your body’s need for sodium. Skimping on salt is a common culprit behind fatigue, headaches, and just feeling blah on keto. Most people could use a little extra salt on keto, but this goes even more for people who live in hot climates or who work outdoors or sweat a lot, and for athletes. If you’re an athlete whose “get up and go got up and went,” and you feel like you’re dragging during workouts, get more salt.

The remedy: Be generous with your salt shaker. Don’t be afraid to go heavy on salt, especially if your diet doesn’t normally include foods that already salty, like bacon or other cured meats, pork rinds, olives, pickles, etc. If you’re not a fan of salty food, consider making a cup of broth using a bouillon cube and make that a daily habit. Keep in mind that salt is only half sodium (the other half is chloride), so to get more sodium, be liberal with salt. Concerned about salt raising your blood pressure? Don’t be. If your blood pressure is normal, consuming more salt has little to no effect on it. In fact, for some people, diets that are too low in sodium bring their own problems10, and high blood glucose and insulin levels coming from too much sugar are more likely causes of hypertension compared to a high sodium intake.11,12

  1. Check your meds.

Don’t blame keto for what your meds are doing! Many medications come with side-effects of decreased energy, drowsiness, or fatigue. Check any medications you’re taking and see if this is the case. The good news is, ketogenic diets can reduce the need for several different types of medication, so if your health is improving, you may be able to reduce your doses or eventually stop taking these drugs altogether (only under medical supervision, of course).5,13 Be especially vigilant if you’re taking medication for high blood pressure. Ketogenic diets have a powerful effect on improving blood pressure naturally, so if you combine keto with the same dose of medication you were taking on a high-carb diet, you might end up overmedicated—meaning, the medicine is now too strong for you because keto is doing the heavy lifting all by itself. Fatigue and lightheadedness are signs that your blood pressure might be too low, but your biggest tip-off might be feeling faint or woozy when you stand up quickly from having been seated or lying down.

The remedy: Work with your doctor to see if keto is helping you get to a place where you can reduce your dose of medications that are making you tired, or possibly discontinue them altogether. Never adjust meds on your own. And consider the possibility that medications that don’t normally induce fatigue might do so when combined with a ketogenic diet. (Most research on pharmaceutical drugs is done in people eating standard high-carb diets.)

  1. Mind your micronutrients.

Low levels or outright deficiencies in certain nutrients can result in low energy and feeling sluggish physically and mentally. The most likely culprit is anemia from low iron or low B12. An omnivorous keto diet that includes red meat, eggs, or seafood would provide plenty of these nutrients, but it’s not impossible for a meat-eater to be low in these. Consuming certain foods doesn’t automatically mean you’ll effectively digest them and absorb the nutrients they contain. Reproductive-age females who menstruate regularly may be at risk for low iron even if their diets include red meat and other iron-rich foods, and this applies even more to those whose diets are low in these.

The remedy: Work with a doctor to have your iron and B12 levels checked. Both are easy to measure with common blood tests. If they’re low, increase your intake of foods rich in these nutrients, or take a good quality supplement.

  1. You might need more carbs. (Eeek!)

If you work out a lot—especially weightlifting, but this might apply to anything high-intensity—you might need a bit more carbohydrate in your diet. Certainly, not everyone does—professional athletes have been going keto and some are breaking records14—but don’t feel bad if you think your performance might benefit from a hit of starch. Plenty of high-level athletes thrive by eating low-carb or keto most of the time, but including occasional carb refeeds or regularly consuming carbs after a workout. You’re not necessarily doing something wrong if you find you need some starch to reach your highest gear in intense activity. Remember, carbs aren’t the enemy. Way too many carbs, too often, is what makes people sick—not occasional infusions of starch for the specific purpose of supporting high-intensity athletics in an otherwise low-carb diet.

The remedy: Increase your carb intake in a sensible way. It’s probably not the best idea to start off with a giant stack of pancakes doused in maple syrup for breakfast first thing in the morning, but consider adding a sweet potato or a serving of black beans or rice to your evening meal on a day you trained hard. Do that consistently and you’ll know pretty quickly whether that small amount of carbohydrate is helping you perform at your best.

If keto has given you more energy and you feel a new pep in your step, great! That’s exactly what we would expect. But if things have gone in the opposite direction and cutting carbs has made you more tired than before, hopefully, you’ve found some solutions here. If none of the possibilities here seem relevant to you, work with a keto-savvy doctor or nutritionist to dig deeper and find out what might be sapping your energy.


  1. Staverosky T. Ketogenic Weight Loss: The Lowering of Insulin Levels Is the Sleeping Giant in Patient Care. J Med Pract Manage. 2016;32(1):63-66.
  2. Mavropoulos JC, Yancy WS, Hepburn J, Westman EC. The effects of a low-carbohydrate, ketogenic diet on the polycystic ovary syndrome: a pilot study. Nutr Metab (Lond). 2005;2:35. doi:10.1186/1743-7075-2-35.
  3. Pointer SD, Rickstrew J, Slaughter JC, Vaezi MF, Silver HJ. Dietary carbohydrate intake, insulin resistance and gastro-oesophageal reflux disease: a pilot study in European- and African-American obese women. Aliment Pharmacol Ther. 2016;44(9):976-988. doi:10.1111/apt.13784.
  4. Di Lorenzo C, Coppola G, Sirianni G, et al. Migraine improvement during short lasting ketogenesis: a proof-of-concept study. Eur J Neurol. 2015;22(1):170-177. doi:10.1111/ene.12550.
  5. Westman EC, Tondt J, Maguire E, Yancy WS Jr. Implementing a low-carbohydrate, ketogenic diet to manage type 2 diabetes mellitus. Expert Rev Endocrinol Metab. 2018;13(5):263-272. doi:10.1080/17446651.2018.1523713.
  6. Mayo Clinic. Diabetic Coma. Accessed Aug 13, 2020 from
  7. Noakes TD. Time to move beyond a brainless exercise physiology: the evidence for complex regulation of human exercise performance. Appl Physiol Nutr Metab. 2011;36(1):23-35. doi:10.1139/H10-082.
  8. Volek JS, Noakes T, Phinney SD. Rethinking fat as a fuel for endurance exercise. Eur J Sport Sci. 2015;15(1):13-20. doi:10.1080/17461391.2014.959564.
  9. Brenton JN, Banwell B, Bergqvist AGC, et al. Pilot study of a ketogenic diet in relapsing-remitting MS. Neurol Neuroimmunol Neuroinflamm. 2019;6(4):e565. doi:10.1212/NXI.0000000000000565.
  10. The National Academies of Sciences, Engineering, and Medicine. Institute of Medicine, Food and Nutrition Board, Committee on the Consequences of Sodium Reduction in Populations. Studies Support Population-Based Efforts to Lower Excessive Dietary Sodium Intakes, But Raise Questions About Potential Harm From Too Little Salt Intake. Published May 14, 2013. Accessed Aug 13, 2020.
  11. DiNicolantonio JJ, Lucan SC. The wrong white crystals: not salt but sugar as aetiological in hypertension and cardiometabolic disease. Open Heart. 2014;1(1):e000167. doi:10.1136/openhrt-2014-000167.
  12. Quiñones-Galvan A, Ferrannini E. Renal effects of insulin in man. J Nephrol. 1997;10(4):188-191.
  13. Hallberg SJ, McKenzie AL, Williams PT, et al. Effectiveness and Safety of a Novel Care Model for the Management of Type 2 Diabetes at 1 Year: An Open-Label, Non-Randomized, Controlled Study. Diabetes Ther. 2018;9(2):583-612. doi:10.1007/s13300-018-0373-9.
  14. Mestel, S. Zach Bitter Is the 100-mile American Record Holder. He Also Eats Almost No Carbs. Men’s Journal. Accessed Aug 13 2020.
By |2020-09-01T09:34:10-06:00August 14th, 2020|Categories: Keto Basics|Tags: , , , , , |0 Comments