Keto Diet Theory Put to the Test

Keto Diet Theory Put to the Test

100 Replies to “Keto Diet Theory Put to the Test

  1. This is the 2nd in a 7-video series on keto diets. In case you missed the first one, check out Is Keto an Effective Cancer-Fighting Diet? ( and subscribe to the video feed to get them in your inbox ( -NF Team

  2. Thousands of people have reversed their type 2 diabetes, cholesterol, high blood pressure, PCOS, infertility…the list goes on…by going on a low carbohydrate diet. Cutting out sugar and grains is the healthiest thing you can do for yourself.

  3. I switched from paleo to WFPB and gained weight. Then I experimented going back and forth and I always get more lean when I cut out grains and increase my fat and protein intake. I appreciate hearing about studies but I can’t deny what the tape measure and the scale tells me. I am desperate to find a way to eat wfpb that won’t make me thick in the midsection. Has anyone else overcome this on a plant based diet?

  4. You're doing your cherry picking again.

    4:44 – The study was done to see PERFORMANCE LEVELS of active crossfit trainers on a ketogenic diet NOT muscle loss- :
    A) " While our n-sizes were limited, these preliminary data suggest that adopting a ketogenic diet causes marked reductions in whole-body adiposity while not impacting performance measures in recreationally-trained CrossFit trainees."
    B) "While individuals in the current study were recreationally trained, we observed no performance decrements 2.5 weeks or 12 weeks after engaging in a KD."
    C) "Moreover, others have reported that aerobic-based athletes experience increases in fat oxidation during running [23], improvements in O2 uptake at lactate threshold after longer-term KD [24], and even improvements in sprint performance [25]."
    D) Their conclusion: "To summarize, our data suggest that a 12-week KD in recreationally-trained CrossFit trainees facilitates improvements in whole-body adiposity without compromising weightlifting, running, or aerobic performance metrics. "

    5:10 – Study was done to review the model not critque falsified information
    A) "Nevertheless, very
    low carbohydrate diets with limited protein likely reduce appetite by promoting an increase in circulating ketones, although the mechanism for this effect is unclear"
    B) "the carbohydrate–insulin model predicts that diets with decreased proportion of carbohydrate to fat, but identical protein and calories, will reduce insulin secretion, increase fat mobilization from adipose tissue and elevate fat oxidation"
    C) "The rise in obesity prevalence may be primarily due to
    increased consumption of refined carbohydrates, but the mechanisms are likely to be quite different from those proposed by the carbohydrate–insulin model."

  5. This is a misleading video. I have tried different diets but only keto works and incrrases muscle mass. The body takes some time for it to be fat adapted. Besides if you eatn to loose weight it is much better when combined with intermitent fasting.

  6. People get that keto is only a temporary state to balance an excess of poor nutrition and lifestyle, right? The first 4 weeks of keto is not easy before becoming fat adapted, allowing your body to use stored body fat as the primary food source. Being 'fat adapted' means becoming easier satiated, it doesn't mean you need to try and consume a daily equivalent in fats. It means the opposite. You eat less easily. Once a day sometimes less. It means you don't need to consume as much. Getting off the glucose roller coaster can help you even out your diet, reduce calory intake and reduce excess insulin production and sensitivity. Vegetables are vital for Keto to work as you need the fibre and minerals. Anyone who skips veggies is playing with fire. As mentioned, once in ketosis, lower dietry fats are needed as they can be absorbed from the body for energy. This means you can up your healthy protein amounts and still be in ketosis. Some are doing this and gaining muscle while training. Also once fat adapted and in an energy 'deficit' (ie. Your body is consuming it's daily requirement from both diet and stored fat) the first fat to be consumed by the body will be fat accumulated around the organs. This has significant therapeutic ramifications (ie. not just for weight loss). It's not therapeutic however when consuming low grade, highly processed oils and fats. It's not meant to be used as a pernanent replacement for a balanced nutrient and fibre dense diet. Instead as a tool for readjustment. Especially for those who've strayed a bit too far from the path. Once back in track can try to change lifestyles and stay healthy, forgetting the need to go back to keto.

  7. The video says that water loss is significant… then blames muscle shrinkage on catabolizing protein (instead of water volume reduction and glycogen depletion)…?

  8. Also, one of the biggest advantage of a low carbohydrate diet for me (based on whole foods instead of processed "replacement foods" like almond flour baked goods, etc.) is the satiety factor. I am full for longer on less calories than on a higher carbohydrate diet (even when it's whole-foods plant based). The study mentioned in this video being iso-caloric handicaps one of the biggest benefits of a ketogenic diet, so of course the study is going to show no benefit vs higher carbs. , do you know of any trials where the two different dietary approaches were tested ad libitum?

  9. Let’s examine the study a little more closely here:

    If we scroll to the very end, we can see the “low carb group” averaged 132 grams per day by the end of the study! That’s not low carb by any stretch of the imagination!

    Experiments and studies are frequently flawed, just like this one. I’ll stick with the observational evidence and what works for me and has worked for hundreds of thousands of others. Countless numbers of people have lost tremendous amounts of weight and been cured of diabetes and numerous other illnesses. Those are the facts and they cannot be denied. We’ve been lied to by the medical community.

  10. First off I will say it's every individuals right to choose what they want to eat, so I have no opinion on whether it's right or wrong. That being said the studies I have seen on keto reference 2-6 weeks to get into Ketosis (depending on the individual). With some saying that no weight loss will happen until Ketosis is achieved. The chart shows a total of 30 days, why would it not show the full 60 days. 15 days seems pointless if you are tracking keto. Also Atkin's is one of many, I personally would lean towards Dr. Berge's keto diet if I was to do so. Regards

  11. 10 years on high carb, low fat, not oil. Still waiting to gain weight. I am lean as f..k and I eat tons of carbs daily with little to not exercise. Same my family on the same lifestyle. My cousins on the other end eating only animal products, cheese and eggs are fat and obese. They always look at me with envy but nobody wants to switch to my eating habits.

  12. what surprises me is that they didn't bury the study or twist the numbers their way. isn't that what big tobacco and big soda does? also, they could have done 1000 more studies. in the meantime, they could have squeezed more money out of everyone. the whole thing is weird… i mean, this is america, right?

  13. First off I follow a keto WOE and have lost 80lbs in a year in combination with intermittent fasting. I have followed vegan and vegetarian diets on the past with no success in terms of weight management. I was aware of the study you mentioned and the issues surrounding it. I would be interested to hear what you would suggest the mechanism is behind the fat loss people experience on a keto WOE is if it is not due to insulin model? As clearly something is going on which enables people to drop the stomach inches. Many thanks.

  14. The only hope for the end of keto is for everyone doing it today to eventually die off while their kids and grandkids learn about veganism and the new generations make it better.

  15. Reading these comments is depressing, people need to step away from tribal “us vs them” mentalities when discussing science and something as important as the health of billions of people. I would like to point out that the Am J Clin Nut 2016 study is far too small to draw any major conclusions from, it was just a pilot study. It does strongly support calorie restriction for overall fat loss though – which isn’t news, but keto and fasting supporters know how easy calorie restriction is on a low carb diet.

  16. So all of the 36 pounds I have lost over the last 6 mo the was just me losing water weight and lean muscle mass despite an increase of my strength while sinultaniously decreasing my body weight? My anecdotal evidence has shown different results for me as an individual.

  17. What about time-restricted diets?

    I eat breakfast at about 7AM, a snack and then dinner at 4PM, nothing else until breakfast. I didn't weigh myself but I did have to add more holes (three) to my belt as the inches melted. This was weight that I had been fighting for years. I'm 53 and had just given up thinking that I couldn't lose the weight because of my age. The diet as it had been before was pretty clean. No sodas, mostly water with low sugar intake. I did and still do have one teaspoon full of sugar per cup of coffee in the moring, mostly two cups sometimes three, outside of that no added sugar. The only differece in my diet was cutting off all calories after 4 PM. Also my energy better. I think it has something to do with insulin resistance. Not that I was diagnosed but if I did cheat and eat something sweat I noticed I started feeling strange afterward. Eyes would go out focus, and energy would be low.

  18. Yeah eating a ton of saturated fat and listening to Jimmy Moores advice on how to be healthy never did quite seem like a great idea.

  19. Only vegans have an average BMI that's considered healthy. I know BMI isn't the best indicator of health, but damn it definitely shows how easy it is to maintain a healthy weight on a plantbased diet. Keto is pure misinformation.

  20. Dr. Greger uses phony-studies, and fake-science. He is 100% WRONG about patients with atherosclerosis! Nuts are deadly for heart patients with clogged arteries. Look at all the reputable, accurate, honest studies published by Dr Esselstyn, and Dr Dean Ornish. Shame on Dr. Greger(who has never treated a patient in his life). He just repeats the false claims from the nut industry. He is actually killing patients with atherosclerosis. I used to be a huge supporter of Dr. Greger. Not anymore.He is dangerous.

  21. If you are not fat adapted, then you can’t expect to lose fat on a ketogenic diet. It takes weeks to months to get fat adapted. In this study, they started out by getting the patients to be insulin resistant and then switching to low carb diet thus setting them up for failure in the short term.
    The ketogenic diet does not work on a short term basis if you are not fat adapted. Eventually you would begin consuming less fat because you would be burning more of your own fat.

  22. 4:17 And that's why we have the carnivore diet. Nice bias, Mr Greger. Wish it held up under scrutiny and not just in the hands of an anti-meat clown.

  23. The smarmy delivery makes me question both the information and motivations behind it. Read the WIRED article. Clicked on a link provided in the WIRED article Read that. Noticed side bar links to pubmed and looked over those. Clicked on one Diet study linking obesity possibly to fetal exposure to High Fructose Corn Syrup during pregnancy. I am suspicious of the funding behind this site. Thumbs down.

  24. Keto has the good result, and It should not be the cause of muscle loss. Others may not do it the right way that is why there's negative results.

  25. It is already known in low-carb practice that water weight is lost in the first 1 to 2 weeks, BUT, after that, fat loss takes place. It is already known that excessive dietary fat can stall weight loss, BUT, knowledgeable scientists and doctors will tell you to increase protein instead of fat when this occurs. It is already known that muscle mass loss occurs during initial fat adaptation, BUT after that occurs, great strength gains can be made.

    Good job focusing on one study from years ago. The reason people do keto is that they see it work in others.

  26. What type of fat was used in the study? What type of carbs? This is the problem with a lot nutrition science. It's oversimplifies food into it's macros, without taking QUALITY into account. High fructose corn syrup is not the same as a sweet potato, and Canola oil or corn oil is not the same as an avocado or grass-finished beef fat. If you conduct a study and give people shitty fat to eat, then yeah, you're probably going to get shitty results. It's so insane. The truth is, you can eat an unhealthy vegan diet, and you can eat an unhealthy Keto diet. Conversely, there are people out there thriving on a vegan diet, and people thriving on a Keto diet, and even a carnivore diet…. Ever wonder that is? Maybe because the importance of QUALITY of food, along with other healthy lifestyle factors (exercise, sleep quality, sunlight, stress levels) supersedes the oversimplification of AMOUNT OF MACROS (protein, fat, carbs)…

  27. Such BS, I went from being a type 2 diabetic and a BMI of 44. My a1c was a 14+. In 3 months it went to a 5.4 and in 14 months I lost 55 lb and my BMI is 21. Keto 💪 baby. Just like a veganism, you can healthy and you can eat crap.

  28. I switched to a keto/carnivore diet 6 months ago. I've had incredible results. I was in good shape before but now my body fat is around 10% while I also managed to add muscle mass. I feel strong and healthy like I'm 25 again (I'm 43). Everything is better now – skin, hair, endurance, strength, sex drive. Everyone I know who actually tried the keto diet has similar success stories. I'm sick of people trying to discredit the keto diet without having actually tried it themselves. I tried a vegan diet for a month once. I felt weak the whole time.

  29. Definitely been proven recently that calories in and calories out is not the only factor for losing weight. Hormone production such as leptin is very important. Clearly he doesn’t like to note that. Also it doesn’t say what was the goal weight so couldn’t their body realize they needed to keep on the healthy weight. Interesting.

  30. I hope vegan keto is part of this series. I started eating salads with olives, olive oil and vinegar and i did lose some weight. Not permanent unfortunately, but i felt pretty good and was going back on it.

  31. Michael Greger is an incompetent buffoon. This is a typically incompetent, misleading, nonsensical garbage from CrackPot Greger.

  32. Ah this was good I needed a good belly laugh ,
    What a bafoon , does not understand science ,
    Here's the real science greger ,
    Get educated you're a joke

  33. Know ya source – this is a vegan channel. So all of us losing fat and gaining muscle with low carb are hallucinating lol. This is capitalism – everyone from the vegans to the carnivores are tyrna sell us someshit and a lot of it is bullshit but as many vegetarians know, raising the carbs regardless of calories makes us balloon up so theres something more complex than just the calorie bullshit and the utopian metaphysical conceptions of the moral vegans

  34. keto is great to get a reset after decades of damage done . for example to fix insulin resistance due to years of overeating and binging sugar .

    weight loss is a bonus .

  35. So why does it work?

    I'm not saying you're wrong or that your research isn't on point but literally everyone I know who has tried the ketogenic diet has lost significant weight, become healthier (I can only verify myself in this claim) and kept the weight off? I went from 240 to 145lb and ended up becoming a semi pro (cat 3) crit racer all while on vegetarian keto, I almost never get sick and my blood panels I get done regularly for cycling are as perfect as they can be.

    My roommate went from 360 and is now at 240.

    My coworker went from 250 to 180 now.

    My cousin has lost 30lbs in 3 months.

    Then there's literally thousands of people on Reddit or other social media reporting the same success. How am I supposed to look at all that clear evidence that takes 0 research to see and buy into this video? The other thing is that you're getting the reason for keto wrong. Yes people talk about more fat burning but that's not the point. The point is appetite suppression and increased energy. You also don't shovel down fat because you're not eating carbs, because of the suppression of appetite you don't eat as much until you get down to a low BMI like me where I do need to increase my fat intake to maintain weight. But on the weight loss journey I was easily able to just slip right into intermittent fasting.

    Then there's piles of research that say the opposite of what your and your research claim. So in a topic even researchers can't agree on I'll go with what I've seen.

  36. Glad you've covered this. I came across taubes and hall and really started thinking…
    Unfortunately the food I have to eat at my placement is full of oil, so I'm worried about combining it with white rice

  37. At the end all we need to do is eat organic and no procced foods, eat everything that comes from the ground of a trees, don't consume meet and exercise.

  38. This argument is grossly flawed. Forcing people to eat the same amount of calories on a keto diet as on a high carb diet misses the whole point of ketogenic fat weight loss. It is the satiety that comes from the fat that reduces the craving for food and thereby lowers overall calorie consumption resulting in weight loss. This is basic Keto 101 and this sort of "fake" science promulgated by this video is starting to get on my nerves. Did you ever notice that when a vegan dies early in life such as the president of the Vegan Society, it's always attributed to bad genes or that they were a "bad" vegan. However it a person on a ketogenic diet dies early, it is due to eating animal products. This is the old "heads I win, tails you lose" scenario. If you were to listen to this doctor you would think that all his patients recover when they listen to his advice. Those that don't, he probably accuses of not following his diet properly. Nature in her wisdom made carbohydrates a NON-essential nutrient, yet today we are hearing that carbs are the MOST essential nutrient. When one does an extended water fast, the body lives almost exclusively on saturated animal (human) fat, for weeks and even months. Lipid blood profiles go through the roof as the body metabolizes its fat. You would think with all this fat coursing the through the veins, the faster would die of a heart attack. I spent several weeks at the True North health clinic and fasted along side many whole food plant based advocates who were fighting diabetes, heart disease, cancer, RA, etc. through fasting. By the way ,Dr Goldhamer runs an excellent clinic which is the best place to go when all else fails and you're in need of an extreme low carb diet.

  39. Congratulations Dr Greg, you're an expert in misleading the entire world into sickness and death. You're pretty much a mass murdered at this point. Hope that some people realize that this video is complete bullshit.

  40. The human body has NO requirement for dietary carbohydrates whatsoever. Also the study you chose has no validity. N=17, there was no control group, it wasn't a double blind random trial of a suitable length of time (ketogenic diets require adaptation) which would be at least 6 months continuously on the diet, whichever diet that study subject was given. If you really want to focus upon the science, get some valid science by choosing a properly conducted, properly designed study with suitable number of subjects and a suitable time line. Also, opinions are worthless. Only the data matters. In fact, just such a valid study has shown that those on a vegan diet do not live longer than a person eating a Standard American Diet. Meaning, there's NO BENEFIT to your veganism. You're welcome. Shame you never actually ever practiced medicine in the real world, but perhaps it was for the best based upon this tawdry hack job you did here.

  41. Yay. Another Vegan channel doing another hit piece on keto full of misinformation. Do your own research. Consider your sources. Draw your own conclusions. I've gone from obese to a normal BMI, gained strength & increased lean mass percentage, reduced bodyfat percentage, lowered my blood pressure and improved my bloodwork on keto. Of course, I'm not pushing a vegan agenda and just do what's best for my own health.

  42. But what happens if you increase protein to compensate? Say 40 to 50 g a day? That might preserve lean muscle mass, increasing metabolic rate, while in ketosis.

  43. The Keto diet is absolute bullshit! Severely restricting carbohydrates is the stupidest thing you can do when dieting. Think about it, when it comes to losing fat ALL it comes down to is being in a caloric deficit. Exercise helps you create this deficit. Guess what fuels your workouts? CARBS! Anyone that follows a keto diet is simply ignorant but now I have informed you so do not do keto. Just eat less, exercise consistently, get enough protein, and make sure you are losing about a pound per week until you reach your goal weight.

  44. Lol. I will decline. I love my fattening meat, dairy, fruit, veggies, honey, maple syrup, and potatoes. I hate beans and grains and that's most of the vegan diet

  45. Thank you Dr. Greger…for bringing light onto this planet. I have used your videos and books as a great source of inspiration for myself, friends, and my Personal Training clients. Slowly but surely, there is shift in human consciousness and our awareness about food happening. You are a maverick leading at the forefront. Keep up the good work!

  46. This guy is a skeleton walking. He has no muscle and I bet if he took off his shirt he would be skinny fat. Sorry doc, but for most people who are already overweight carbs will block fat loss guaranteed. Even though this guys channel is called nutrition facts, it really should be called nutrition opinion. This guy is so plant-based biased it's obvious. As a personal trainer with 14 years of experience i can tell you that keto is the best diet for getting people to lose weight.

  47. The interesting thing is, there’s actually plenty of research that keto works, more than research proving it doesn’t work or the results are the same of just normal caloric restriction. I’ve been reading the past few weeks and the information is out there.

    But none of that was mentioned in the video. I wonder why! After doing some research this Channel/ site’s agenda is to promote a 100% plant based diet, meaning most other diets, including Keto are their enemy, and even more so due to Keto’s popularity.

    And lastly, NutritionFactsOrg has a moderate pseudoscience rating (mediabiasfactcheckcom), meaning they have bias and make exaggerated claims using cherry-picked material. Yikes!

  48. This is not what I’ve seen in real life. I am strict vegetarian, almost vegan. But I know people, work-related, who are doing Keto. They are in excellent physical condition, particularly for their age. They have tons of energy, and are very athletic now since starting this whole Keto thing. They have lost body fat, and are lean and trim and super active. Other people who are consuming high carb diets, appear to be taking drugs, as the carbs seem to make people sleepy after eating them, and sluggish. They don’t think as clearly, and are slower and less engaged. It’s like carbs act as a mild narcotic.

  49. I lost 10 lb by Keto diet, and keep my weight for more than 2 years now. And my son lost more than 20 lb after 2 months of switching to Keto. The reason is that the keto diet makes me eat less total calories. I guess if you keep the same calories, the keto diet may not work well.

  50. I would say, bullshit!! I lost 23 kg in 5 months, reduced triglycerone score, lowerred my blood pressure, reduced the amount pills taken everyday, and all that with keeping the level of mussle ratio, reduced fat. So i dont realy understand what are you talking about, did i lose 20 kg of water??

  51. These videos are so hilarious. If you just change to a low carb high fat diet and add intermittent fasting,… your experience will tell you how full of sh!t Greger is.

  52. Vegan hacks desperately trying to discredit anything that goes against there self biased agenda narrative leftists cultist beliefs…. he sure likes to hear himself talk

  53. *****DISINFORMATION ALERT*****. What is missing is the assumption that keto lifestyle people eat the same as carb-eating ‘normies.’ On a keto diet, although initially interesting, you cannot continue to eat fat at the rate that normies cram carbs. I know from personal experience. As a keto practitioner, I have to focus on eating ENOUGH fats (healthy fats, btw, like organic ghee, grass fed beef fat on meats, etc). The key to keto is to combine it with intermittent fasting. The reason the combination works so well is the satiety value that fats have allows one to go from meal to meal without snacking (spiking insulin). As far as the muscle issue is concerned, part of the reduction. Is due to the effects of making the muscle more healthy. As autophaghy is allowed to occur, the body cleans out less efficient/diseased tissues and replaces them with healthy tissues. Inflammation also flees the body, so what a person is getting, initially, is a more honed muscular system, free of diseased, inflamed tissues. For the fat loss, yes, it does go down, but that is only in response to being more fat adapted. The body is now using fat instead of carbs/sugar as a fuel, so it becomes important to keep a little around, but we are talking about the body naturally resisting going below 3-5% body fat levels…. at that point you will be ‘shredded’ (8 pack time). This video also completely avoids talking about the benefits of keto: less inflammation IS LIFE CHANGING. Seriously. Inflammation is a killer that the whole ‘sickcare’ industry feeds off of. Do more research before throwing out the baby with the bath water, as this video would have you do.

  54. Of course you will get fat if you eat too much, whether carbs or fats. Keto just has the added benefit of reducing hunger which makes easier to follow a calorie reduced diet and loose weight.

  55. So dumb to keep arguing over which diet is better when they both work fine. Carb/plant based diet for summer when fruits are ripe and fat/animal based diet for winter when animal carcasses are the only available food source. Just don't live your entire life in a single season.

  56. This is fear mongering. I liked your video on the the nutrition committee, but this is lazy. You talk about the insulin model, but neglect to flesh out how that effects the body, or how the insulin model could be tested and studied.

    OF COURSE the participants of that study would burn more muscle DIRECTLY after switching from high carb to low carb! That is well known! Simply changing the diet doesn't immediately change your hormonal responses. Dear doctor, you are a bad scientist. That's all this video has proven.

  57. From

    To summarize, our data suggest that a 12-week KD in recreationally-trained CrossFit trainees facilitates improvements in whole-body adiposity without compromising weightlifting, running, or aerobic performance metrics. However, our finding that KD may reduce leg muscle mass suggests that, over prolonged periods, the diet could adversely affect muscle anabolism and warrants further human investigations using sensitive histological techniques. Additionally, given our observation that KD increased serum LDL cholesterol levels, more research is needed regarding how longer-term KD engagement affects blood lipid levels in normolipidemic athletes. Notwithstanding, the novelty of this study examining how a longer term KD affects anaerobic performance metrics continues to contribute to field of sports nutrition and challenges the paradigm regarding very high carbohydrate needs in anaerobic trainees or athletes.

  58. Funny to think how i started out as a vegan about 4 years ago (nolonger) to now I can not stand videos about diet or food. This video was in my suggestion and I immediately felt irritated. I’m so sick of the contractions around it’s and food , who’s right, who’s wrong that i literally gave up being a vegan. It’s literally too much. Who knew eating could become so dam complicated

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