Are Keto Diets Safe?
Are Keto Diets Safe?

“Are Keto Diets Safe?” Given the decades of use
of ketogenic diets to treat certain cases of pediatric epilepsy,
a body of safety data has accumulated. Nutrient deficiencies would
seem to be the obvious issue. Inadequate intake of 17 micronutrients
—vitamins and minerals— has been documented in those
on strict ketogenic diet. Dieting is a particularly
important time to make sure you’re meeting all your
essential nutrient requirements, since you may be
taking in less food. Ketogenic diets tend to be
so nutritionally vacuous that one assessment estimated
that to get a sufficient daily intake of all
essential vitamins and minerals you’d have to eat more than
37,000 calories a day. That’s one of the advantages
of more plant-based approaches. As the editor-in-chief of the Journal of the American
Dietetic Association put it: “What could be more nutrient
dense than a vegetarian diet?” Choosing a healthy diet may be easier than sticking 50 sticks
of butter in your coffee. And we’re not talking about just
not reaching your daily allowances. Children have gotten
scurvy on ketogenic diets, and some have even died
from selenium deficiency (which can cause
sudden cardiac death). The vitamin and mineral deficiencies
can be solved with supplements, but what about the
paucity of prebiotics, the dozens of types of
fiber and resistant starches found concentrated in
whole grains and beans that you’d be missing out on? Not surprisingly, constipation
is very common on keto diets, but as I reviewed before, starving
our microbial self of prebiotics can have a whole array
of negative consequences. Ketogenic diets have
been shown to reduce the richness and diversity
of our gut flora. Microbiome changes can be
detected within 24 hours of switching to a
high-fat, low-fiber diet. The lack of fiber starves
our good gut bacteria, but we used to think dietary fat itself was nearly all
absorbed in the small intestine. But based on studies
using radioactive tracers, we now know that about
7% of the saturated fat in a fat-rich meal can
make it down to the colon, which may result in detrimental
changes in our gut microbiome, weight gain, increased leaky gut,
pro-inflammatory changes. For example, a drop in
beneficial bifidobacteria and a decrease in overall
short-chain fatty acid production, both of which would be expected to increase the risk of
gastrointestinal disorders. OK, but striking at
the heart of the matter, what might all that saturated
fat be doing to our heart? If you look at low-carbohydrate
diets and all-cause mortality, those who eat lower-carb diets
suffer a significantly higher risk of all-cause mortality,
meaning they live, on average, significantly shorter lives. From a heart disease
perspective, though, it matters if it’s an
animal fat or plant fat. Based on the famous Harvard cohorts,
eating more of an animal-based low-carb diet was associated
with higher death rates from cardiovascular disease—
a 50 percent higher risk of dying from a heart
attack or stroke— but no such association was found for lower-carb diets
based on plant sources. And it wasn’t just Harvard. Low-carbohydrate dietary patterns
favoring animal protein and fat, from sources such as
red meat and chicken, were associated with
higher mortality; whereas those favoring
plant protein and fat, from things like vegetables, nuts,
peanut butter, whole grains, was associated with lower mortality. Cholesterol production
in the body is directly correlated to body weight. Every pound of weight
loss by nearly any means is associated with about
a one-point drop in cholesterol levels in the blood. But put people on very
low-carb ketogenic diets and the beneficial effect
on LDL bad cholesterol is blunted or even
completely neutralized. Counterbalancing changes
in LDL size or HDL (what we used to think
of as good cholesterol) are not considered sufficient
to offset this risk. You don’t have to wait until
cholesterol builds up in your arteries, though,
to have adverse effects. Within 3 hours of eating a
meal high in saturated fat you can see a significant
impairment of artery function. Even with a dozen
pounds of weight loss, artery function worsens
on a ketogenic diet which appears to be the case
with low-carb diets in general. So, bad for the gut,
bad for the heart, but is it bad to the bone? We’ll find out next.

100 thoughts on “Are Keto Diets Safe?”

  1. says:

    Check out all of the keto video so far: -NF Team

  2. Kayondo Thomas says:

    Lol, this is laughable. You can't draw conclusions on the safety of the keto diet in just 5 mins. I can present a few journals from PubMed talking about the dangers of a Plant based diet, does that conclude that Plant based diets are not safe?.. Everything is Quality & Quantity dependant Dr. Greger!

  3. seguiriya1 says:

    Word of advice for new listeners, put video speed at .75 when listening to Greger as he tends to fly.

  4. Mike Symth says:

    The Lancet paper in this video concluded “Bothe high and low percentages of carbohydrate diets were associated with increased mortality with the minimum risk observed at 50-55%carb intake.” So this says a vegan high carb diet is associated with increased mortality. This conclusion is opposite of the results of Dr. Esselstyn’s heart study on real patients

  5. Leonard Schmitt says:

    this is going to all my low-carb friends instantly <3

  6. Mike B says:

    Keto Diet… – I have type II Diabetes?? How??! I never eat Carbs! Why am I so fat? Oh I must be fasting wrong… Pass the butter wrapped deep fried Bacon Shrimp Pork Lard balls!

  7. Mike B says:

    Thank you Dr. Greger. Unfortunately a friend of mine is so stuck on the KETO TARD side of the diet she honestly believes that it's HEALTHY…. Posted a MEME on IG and she replied… Instead of embarrassing her (I've known her for more than 20 years) I just deleted her comments… I figure in the next couple of years when KETO does in her body she'll finally realize that she was wrong… OR She'll say.. "OH I must be fasting wrong…" Because that was literally one of her comments.. Something about fasting, which was entirely nonsense and garbage.. Was funny.

  8. Mike B says:

    The Keto Diet… when flexible Arteries are for wimps!

  9. Lloyd Christmas says:

    Who the hell wants to take advice from some skinny doctor? I get my low carb advice from obese Jimmy Moore.

  10. L1ght 111 says:

    Instinct karma diet. Kill the animals heart and in seconds it start killing yours

  11. Jeffery Jeffery says:

    I like Dr. Greger a lot. BUT…

    This article is quite misguided. I eat a TON of whole vegetables. Have a TON of fiber!! And also eat fruit. BUT….I am also, most definitelt in ketosis!!

    I had terminal cancer, with only a 10% chance of living a year. But now they cant find it. Yes…I put some butter in my coffee.

    Heres the thing…..people are so misquided, as we believe if this is good…then Ill double down, and it will be even better.

    Same thing with Keto Diets!! People are taking it WAY to far!!! Taking keto to the extreme!! And that ultra restriction…IS NOT!!!!! IS NOT, a Keto Diet!!

    That's called a starvation diet, which is what Dr. Nerg is actually referencing!!

  12. 80 Slim Shady's says:

    I hope that moron Ken Berry sees this stuff

  13. MIchael C says:

    Would you do a story on the benefits of garlic please?
    I grow it in BC and can refer the video to customers.

  14. Emily BH says:

    Never mind the most o b v i o u s thing about keto is that it is acid forming. In order to have a moving healthy lymphatic/immune system our bodies need to be alkaline to maintain fluidity and prevent congestion, plaque, hardened mucus tumors etc. You can't possibly do this when all you are taking in is dead cooked aimals. How can anyone imagine they can derive anything beneficial by eating flesh from dead animals that is weeks or months old and on top of that is c o o k e d ? All people need to figure these things out is some critical thinking and c o m m o n s e n s e.

  15. I I says:

    I’m on vegan keto right now

  16. luna57 says:

    Unfortunately, children with epilepsy on a keto diet were often given products like "KetoCal" instead of a healthy, whole foods keto diet. The main ingredient? Refined Vegetable Oils (Palm, Soy, High Oleic Sunflower)

  17. R. Ann Rousseau says:

    Oh my god. This is crap.

  18. A. S. VanHoose says:

    Every Keto dietier response to this series is going to be: 'That's not MY Keto diet.'

  19. Zeh Ven says:

    Brewer yeast and shell fish. Simple

    The study's what say low carb aren't low.

  20. luna57 says:

    Regarding the study mentioned at 4:18 – If you look at the actual study, the meal was a piece of carrot cake and a milkshake! I guarantee you nobody on a keto diet is eating carrot cake and milkshakes. This study is meaningless in regards to the keto diet. Haven't time now to look up all the other studies mentioned, but I wonder how many of them actually studied true low carb diets, or even low carb diets at all.

  21. UnbiasedHuman says:

    Bart Kay just exposed your bias and lack of integrity once again.

  22. Shaon Sarkar says:

    But, what about keto diet with Lots of leafy greens & vegetables? 🤔

    problem solved 🤗

  23. Daniel Pugge - Keto Sport says:

    I had to laugh a bit when I saw supporters of the first study. They make vitamin pills. So vitamin pills are to be sold to people who are on such a diet. A ketogenic diet of 1500 kcal can cover more than 100% of all nutrients. And that with 30 g carbohydrates per day, i will make a Video soon (Without any organ meats or supplements). Mortality?

    Many people who start such diets are already overweight. It is therefore not surprising that these people become ill.

    Greger's way of working is anything but scientifically neutral. Nice move, but easy to debunk 😉

  24. Evan Deitrich says:

    No, no, and no.

  25. Lauren Burger says:

    Those on the Keto Diet are Dying to know if what they are doing is healthy… Interesting…

  26. L1ght 111 says:

    Flesh may have some nutrients because your flesh has plant nutrient in it. Second hand nutrients. So every time you give credit to flesh, your only giving credit to plants nutrients. Kill the animal to get second hand nutrients from flesh only to kill yourself and the animal is illogical.

  27. Jay and Vicky says:

    Love this keto video series! Keep cranking these out, Dr. G! I can't get enough.

  28. UnbiasedHuman says:

    Wake up people, you're being brainwashed to think that these poorly conducted scientific studies can prove anything to you. Do some research yourself and read the actual studies before listening this guy reading the conclusions and implying that they can prove something. We don't even know what people actually eat in those studies.
    "Michael Greger Incompetent Buffoon. AGAIN" :

  29. chiyerano says:

    Thank you for stating the differences found from the effects of plant based fats and animal based fats in keto or low carb diets. Always thought there was a difference as long as the plant based fats were naturally occurring.

  30. Donald Anderson says:

    Thank you for your work good Sir!

  31. Leonardo Da Vinci says:

    "Dr" Berg won't be happy about this LOL

  32. Marc Montti says:

    Keto is like antibiotics

  33. The mirror of the truth says:

    Great video thanks for the information

  34. fandango costner says:

    Long term studies have shown vegan diets have the same morbidity and mortality incidence (of normal causes of death and disease) as a std American diet. No one disbelieves that vegetarian or vegan is better than eating poorly, however the exclusion of good fats in the diet have detrimental effects which if known can be corrected. Same with healthy Keto or Paleo, Adkins diets.

  35. Victoria T. says:

    I am against any diet. Stick to your body's needs, listen to your body.

  36. SouthernStar says:

    Will you and Dr Gundry PLEASE go head to head….
    I need to see all the hot air spewed.

  37. TheMrGrafixable. says:

    My man laying the smackdown

  38. Marla Jacques says:

    Bad for animals, bad for the environment, bad for the body…yup it's not complicated. For most tho, they'll never stop for that 5 min taste of their carcass that has to b covered in sauces and spices

  39. Daniel Lugo says:

    please make a video about distilled water…is camembert ok for B12?

  40. nope says:

    All the down votes from pissed off keto dieters that have now delved deeper into their delusion and cognitive dissonance.

  41. michael onello says:

    Thank you Dr. G……..Instagram = mikewakethefoodup

  42. rawbirbella justthat says:

    This Keto-Series is just fantastic!!! Totally impressed!!

  43. Christina V says:

    Dr. Greger would you be able to debate Dr. Berg, he isn't vegan but despite pushing ketogenic diets / intermittent fasting he always focuses on low glycemic index foods ; so he pushes people to eat 7-10 cups of leafy greens in a day and he pushes for healthy fats and makes videos that can be vegan friendly ! I would love to see you both get to the core of these opposing views together in a video and maybe you can convince him to go vegan 🙂

  44. Tayloch says:

    Just for the keto dieting moms out there who are skeptical, vegan-keto diets are a thing too, so Gregor isn't bias against keto.

  45. Iron Vegan says:

    The evidence is mounting! This type of stuff would scare me if I were a proponent of the Keto way of eating. I'm eagerly watching to see if the popularity tide towards Keto begins to turn in the next year or so.

  46. Joe M says:

    I have to wonder if Dr Gregor is deliberately or mistakenly conflating the Atkins diet and ketogenic diet? A proper Keto diet is 70% vegetables and 30% fats & proteins.

  47. Jack Jackson says:

    People on a keto diet for 5 years states her LDL, CHOLESTROL etc are all "perfect" I asked her what the results were on free radicals, pcbs, ddt, toxins & dioxins were? *drew blank 🤷‍♂️

  48. odizzido says:

    I wish coconut were healthier 🙁

  49. Alfonso Sosa says:

    Again… amazing work!

  50. Doug bananaboy says:

    Animal Fat and oils and coffee for the win

  51. French blue8 says:

    What could be more nutrient dense than a vegetarian diet???
    How about a balanced whole food plant-based vegan diet?

  52. Daniel Lugo says:

    is there any good site where can you can type certain types of fruits like apple and you can get a whole list of nutrients like Vitamin C, Selen and all that stuff?

  53. o_o' says:

    Anyone who thinks eating blocks of lard, heavy cream, and fatty meats is safer over starchy vegetables, fruits, and whole grains deserves what’s coming.

  54. Ash Khan says:


  55. Vegan4Life says:

    I know a few people who did keto long term and had serious health problems as a result. One guy 29 years old he was in great shape and keto for 6 years he had to get on meds bc his triglycerides were through the roof and so was his cholesterol.. luckily he was able to improve his numbers and get off the meds by changing to a more plant based diet.

  56. Vegan4Life says:

    Really loving all these videos Greger has been doing calling out the keto diet!! 👍👍🌱 So many people are learning the hard way. Too much misinformation out there.

  57. Max anders says:

    how the hell do u get lack of minerals by only eating meat?

  58. David C says:

    Bloody hell the amount of times I’ve heard keto diet fans say a vegan diet is deficient and there they are with data that keto diets are deficient in 17 different nutrients 🤯.

  59. José Manuel Arteaga Guzmán says:

    Half a million, doc! Let's celebrate!!!

  60. Vynland says:

    Source: TRUST ME BRO

  61. BabylonianDynamics says:


  62. Tom Soya says:

    There are many thoughts out there but almost all agree that beans are almost the perfect food.
    Now where did I put that 11 bean chilli ???👍

  63. Dr. Darren Schmidt, DC says:

    -I counted 7 epidemiological studies regarding the heart. Garbage "science".

    -A change in the organisms in your microbiome is inconsequential. Notice the use of the word "may" in the vid.
    -The endothelial function soon after a meal doesn't equal heart disease in the long term.

  64. Carlos Frederico Cavalcante says:

    too biased…

  65. Alchemist-A says:

    I wish you would put together a good slide presentation on the subject sticking to the science and cutting out the stupid jokes and the ridicule. Flashing by images of papers and simply highlighting the text that supports your conclusions is not the proper method of critiquing anything.

  66. Tony Olson says:

    OMG!!!! You can eat dark greens and cruciferous veggies when on the Keto diet, as well as berries. I do it all the time and stay in Ketosis! Dark greens are the most nutrient dense foods there are! You can also eat vegan on a Keto diet (I do!), by eating avocados, nuts, and seeds!!!! I love how Gregor cherry picks his “evidence” to push his own agenda!

    It’s a myth, perpetuated by vegans, that Keto dieters just shove lard down their throat all day!!!

    The following 2 studies proves Gregor wrong. And this study is a random double blind study, not some cheap observational (epidemiological) study like Gregor likes to use. Only a random double blind study can prove causation! The following study followed people on a Keto diet for several weeks and their blood chemistry improved all around, and they suffered NO nutritional loss! The other study was for 24 week! Same results. People all lowered their total cholesterol, LDL, triglycerides, and raised their HDL! All good things!

    Does Thomas DeLauer, who stays on the Keto diet most of the time (just goes off if for photo shoots, when he eats carbs to add water to his muscles), look like he suffers from malnutrition?!? Who would you rather look like, Thomas DeLauer or Gregor?!?

  67. Swiss Lady Driver says:

    Yawn. Low carb/high fat for the win. My gut has never felt better.

  68. Fruity Ricky says:

    I've had my own diet journey in the vegan world and let me tell you, i've done fruitarian and also banana island which clearly helped me lose weight, only downfall i kept pooping and always was hungry / been on HCLF raw til 4 lost TONS of weight but i am very sensitive to grains, beans, wheat and rice (lectins created more inflammation, gluten is the worst) / so far i've had the most success on a keto HEALTHY vegan diet

    There is more than one keto diet, keto junk food diet / keto vegan junk food / vegan healthy keto.

    I do agree that you need to monitor nutrients really carefully, because most people are doing it wrong. Most of wrong ketoers go too high on animal products( like stated in Dr Greger's video, you want to avoid animal food sources 3:21 ) or they go too high on protein intake or they way too low on the veggies. However, when done properly, a vegan keto diet will 1) boost growth hormone(weight loss and muscle growth are boosted dramatically) / 2) lower insulin resistance / 3) eliminate lectin issues from high carb low fat diets(HCLF often centralize around beans, potatoes, rice or wheat gluten) / 4) get rid of hunger that often happens on a HCLF because insulin is NEVER going up and down

    Vegan HEALTHY keto: 1) Avoid carbs because high fat will impair insulin function 2) get most calories from avocadoes / walnuts(tons of omega3) / coconut oil / ground flax seeds , 3) add tons of vegetables, greens and salads 7 to 10 cups daily 4) do not go high protein intake, it has to be moderate or the liver will suffer from it 5) Hardcore repair: after having all your nutrients checked and after many weeks of vegan keto you may consider intermittent fasting(16+hours) to trigger autophagy (which is body's repair mode where flawed proteins gets recycled as energy or as new building blocks)

  69. Linda PB says:

    I ❤️ Dr. G

  70. Daniel Dias says:

    how about gallstones on vegan diet?

  71. Pep X says:

    You are not going to get Keto people to switch to a plant based diet through this negative type of video. Surely this can only be achieved if information is presented in a positive way to show the benefits of plant based and then allow individuals to make up their own minds about who has the better argument and which appeals more to their lifestyle and goals.

  72. josh Kundrat says:

    Can you address this paper sometime

  73. lightdark00 says:

    Notification squad reporting! Nine hours late since it took that long for YouTube to give one.

  74. Matt Lauer says:

    Did this guy ever even actually practice medicine?

  75. Luis Schay says:

    Dr.: Still you don't say that keto diet is good for type 2 diabetics, high blood pressure and high triglycerides.

  76. Shabba Ranks says:

    here come to the double digit IQ ketotards

  77. Miguel Mora says:

    Problem is he never mentions plant based low carb diets as an option. Why would i be defficient in sellinium if I have brazil nuts; or in fiber, if there are plenty of green veggies? Scurvy… with the existence of broccoli, blackberries, blueberries and lime/lemon?

    Such a deviation from his comment on the matter when he compared the "eco-atkins" vs the normal vegan diet and stated that as long as it was plant based, macros didnt matter, and the mortality rate was even lower. Now he only criticizes keto in the form of animal rich diets.

  78. I like Potatoes says:

    So this is where vegan zombies who can't read for themselves hide.

  79. GawdSpeed says:

    False,biased misinformation

  80. Brian Parsons says:

    Dr. Greger, please find studies of keto done the CORRECT way and discuss that (I won't be holding my breath on that because, I suspect if/when you do find those studies, they won't be in line with your agenda, so you'll simply move along without discussing). Keto done the correct way is:

    This might be a shock to you, but keto actually includes a STEADY (As in daily) stream of lots of plant food, like veggies, dark leafy greens, nuts, seeds, avocados, coconut and MCT oil, etc. Yeah, it deviates from plant food by adding in animal food as well like WILD CAUGHT salmon, WILD CAUGHT chunk light tuna, PASTURE RAISED sourced eggs and chicken, 100% GRASS FED AND FINISHED beef and butter (i.e. stay FAR away from the GMO grain fed food), and you've got keto done the CORRECT way. In addition to that, you add regular exercise and intermittent fasting, and that completely rounds out the CORRECT way to do keto. Got it? Understand???

    I hate the fact that there's all this vegan vs. keto going on. Do you all not realize that there's actually a fair amount of overlap in these lifestyles?

    What you're talking about in all of these hit pieces (Let's call them out for what they truly are) is NOT keto. It's almost more so atkins, or what I call dirty keto (i.e. the GRAIN FED SOURED bacon and butter way of eating).

  81. cajunbargod says:

    You say keto then you show an Akins model. By no means is this the same thing. Look into Dr. Steven Phinney. Dark greens are pushed more along with high fiber and low carbohydrate or net carb. Chia seeds or even flaxseeds are promoted in this lifestyle. The latest studies from Dr. Steven phinney and Perdue university talk about the microbiome and Improved health markers.

    I enjoy your information but to say keto and the put Adkins is not a true statement. Why not reach out to those that have published papers on how a keto lifestyle with suppressed feeding windows has been used to affect cancer in a positive way. Especially since cancer is a metabolic disease of the cell. Relying on carbs to continue their fermentation process.

  82. cajunbargod says:

    This is funny how you are also concerned about heavy metals in the seafood yet it is purely fine to inject someone with it and call it an adjuvant or better yet to be used has a sterilizer.


  83. ggzh a Argue With Everyone says:

    And how many deficiencies are there in other diets? The numbers are meaningless if you do not compare them to other diets.

  84. zukodude487987 says:

    There weren't many keto videos on this channel…


  85. MMM mm says:

    What is a safe way to get off the keto diet?

  86. Peter Rabitt says:

    But insulin, tho. But ketones, tho. But vitamin K2, tho. But bone broth, tho. But collagen, tho. But meat heals, tho. But Eric Berg, tho. But Charles Poliquin, tho. But bulletproof coffee, tho. But Tom DeLauer, tho. But Maasai, tho. But Inuit, tho. But Timothy Noakes, tho. But Peter Attia, tho. But Sarah Hallberg, tho….

    I could go on for MILES.

  87. Kevin Jorgensen says:

  88. Cam Whitman says:

    Lies, lies, lies. A plant-based ketogenic diet does all of those things; not a meat-centric ketogenic diet.

  89. AheadoftheHerd says:

    Thank you, Michael Gregor, for your dedication to public service.

  90. DayTime Dave says:

    Silly man. Biased cherry picking of data.

  91. dejan valjak says:

    One month KETO, one month vegetarian, also 1 month OMAD and one month plant b. Diet ( the combination of all – best results!!!
    I don't now why so many hate about the KETO tool for cleaning the body from the toxins… nothing will happen to try 1 month from all and you will decide which is best for you (BONE PROBLEMS?) Not so sure, please check this video and tell me more about it, I love to learn and know as more as possible about our food combination

  92. Steve says:

    How is a keto diet lacking in deficiencies? Ur suppose to eat 8 to 10 servings of veggies.

  93. Dani Jan says:

    regards to nutrition everyone can pull studys about anything proving everything

  94. greeninjaize says:

    This seems incredibly biased. "50 sticks of butter in your coffee" come on. Also you're allowed loads of veg on keto, you're acting like it's literally just fat.

  95. Admin 2018 says:

    You know that thing where someone presents such BS that they have to keep trying and keep trying. That what Keto/ carnivore diet people sound like. They have to convince themselves but the data just isn’t there.

    It’s only obvious to every person that plants are healthy and tons of fat and meat is bad. It’s like it’s wired into our being.

  96. AetherDreamSeeker says:

    Good thing I love my hummus and fruit too much to go keto.

  97. JWK says:

    Vegetarian/Vegan diets = higher risk for stroke than meat eaters. #breaking news.

  98. Bid Now says:

    Kevin Hall just tweeted that the conclusions presented here do not accurately depict his studies.

  99. Carel Joubert says:

    And so the debate continues

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