Doctor's Note

For more videos on meat vs. plant-based diets and health:
Meat and Weight Gain in the PANACEA Study
Chicken Big: Poultry and Obesity
Paleo Diets May Negate Benefits of Exercise
Uprooting the Leading Causes of Death

Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. And check out the other videos on omnivoresflexitariansvegetarians, and vegans. Also, there are1,449 other subjects covered in the rest of my videos--please feel free to explore them as well!

For more context, check out my associated blog posts: Preventing and Treating Kidney Failure With DietPoultry and Penis the first month, Boosting Gut Flora Without Probiotics,The Ice Diet, Poultry Paunch: Meat & Weight GainPlant-Based Diets for Metabolic Syndrome, and  Plant-Based Diets for Fibromyalgia

  • Michael Greger M.D.

    Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. And check out the other videos on omnivores, flexitarians, vegetarians, and vegans. Also, there are 1,449 other subjects covered in the rest of my videos–please feel free to explore them as well!

  • Novecento

    In my opinion this huge gap in weight between vegans and meat eaters can be explained with junk food.

    Although there may be vegans eating pasta and chips, most of them eat an abundance of whole foods including fresh vegetables and whole grains (the majority of which not from wheat).

    The majority of meat eaters are also junk food eaters, having plenty of refined wheat flour and sweets, a cause of excessive weight more than meat itself. The quality of their meat is also low and very high in fat.

    So if we were to compare veganism with a diet full of whole foods including a moderate amount of lean meats and fish, I think the average weight of the two groups would be very similar.

    • Heather Rhine

      although, you do have a point, do you believe that flexitarians and vegetarians also eat more junk food than vegans?  these people also care about their diet.  why is there a difference between the average weights of flexitarians and vegetarians?  this difference between their diets is only a small amount of meat.

      • Alia XxX

        I think vegetarians and flexitarians are more interested or more addicted to food than vegans. It is not easy to give up dairy products, not easy. And in my personal opinion a vegan is someone who is dedicated to their diet for various reasons and they will not step wrongly. For a vegetarian and/or a flexitarian it might be easier to eat not necessary junk food but foods that can make fat deposit? It is just a guess.

      • Cleo Thompson

        Heather: I would start with a disclaimer to the effect that BMI is a precise enough measure for large scale screenings, but it’s far from perfect for assessing health on an individual level. That out of the way, it’s extremely difficult for a raw-food vegan or a vegan that avoids processed foods to overeat, and their body composition tends to be a reflection of calorie-restricted dieters. It could easily be the case that flexitarians and vegetarians are simply more muscular. Anyway, my point being that there’s no way for us to know what the difference is because all we have is BMI.

    • Jay

      Eating meat shifts the ratio of gut bacteria. With increased meat consumption, the ratio of Firmicutes to Bacteroidetes in the intestines increases. This causes weight gain. Meat consumption also changes the ratio of other bacteria in the body that typically causes weight gain.

    • Israel Navas Duran

      You seem to be obsessed with wheat. I can’t remember of any of Dr Greger’s videos in which he stated that wheat was a particularly unhealthy food. You may know that not everyone is a celiac (between 0.2 and 1% of the US population), and there are other cereals like barley and rye that celiacs must avoid. As for gluten sensitivity, according to some sources is about 5% of the population, and I bet that it’s concentrated among those with poor dietary and lifestyle habits.

      • David

        Wheat is my favourite calorie-dense source (being raised in Italy may have played a factor), also when whole. So I hope you are right, but I will look for Dr Greger’s videos on wheat just in case ;)

  • ed

    Makes sense to me.  18 months ago I went vegetarian at 240#.  I also dramatically reduced my consumption of dairy and eggs but not cheese or Greek yogurt. So I can’t quite claim Vegan.  Today I weight 190# which is my ideal weight.

    • Michael Greger M.D.

       That’s fantastic–congratulations!

  • Michael Greger M.D.

    Please also check out my associated blog post, Poultry and Penis Cancer!

  • Liakay00

    I agree with some of the others – it may be that junk food is accounting for a lot of the difference in weight. It might be that vegans are more careful about what they eat (especially the ones who’re vegan for health reasons). Or that there is way less junk food that has no animal products in it, and so less opportunity to eat junk.

    This is especially true when eating out. Even the vegetarian options have animal products all over it (like butter, cheese, etc.). And with a lot of Americans eating out a lot, and very few vegan options on average, I bet a lot of vegans make homemade meals a lot of the time. I mean, we can’t even eat ramen in a cup. And you can only consume so much rice and pasta before you’re re really full.

  • Liakay00

    Oops, I hadn’t finished.

    But, this is a very interesting study and I do think that being vegan has health benefits. I’m a vegan mostly because of how animals are treated, but I really like the healthy side effects.

  • Iivari-Matias Hammonds

    This study is very inspiring. I became vegan only a week ago, but I’m really worried, because I’m already borderline ‘underweight’ and am really trying to build up to a healthier weight and keep it there. With the food options being so healthy and fat-free, is that even a realistic goal, do you think?

    • Richard S Brown

      A healthy vegan diet (lots of greens & raw plant based foods – no junk) will get you to a healthy weight. If you think you look too skinny then  go to the gym and pump some weights.  You will have so much more energy as a vegan it becomes easy. There are many professional body builders who are vegan… nuf said.

      • Iivari-Matias Hammonds

        I wasn’t sure if having fewer sources of protein would stunt it, since so many ‘muscle builder’ drinks have milk based solutions in them, but that’s a really good point about the extra energy… After some research, I find alot of footballers are surprisingly vegan and, like you mentioned, body builders. Thanks very much for the feedback, sir!!

    • Toxins

      All whole plant foods contain a mix of all fats, so these foods are not fat free, but low in fat. Try to consume starch based meals, as these tend to be calorie dense, nutrient dense and quite satiating. Starches include brown rice, quinoa, wheat, beans, oats, corn, potatoes, etc.

    • Carol Wexler

      Eat plenty of plant foods which contain fat like avocados, nuts and seeds. Roasted pumpkin seeds are fabulous as is or sprinkled over grains.

    • Ann

      Might be worth consulting with a vegan-friendly nutritionist if you’re unsure. Body weight is only one parameter, so other things to consider would be healthy muscle mass (as mentioned), your unique body size & type, making sure you’re eating a diet that includes all needed nutrients in adequate amounts, and limiting or eliminating nutrient-poor food until you feel confident you are in good health. There are now many vegan junk and processed foods on the market, enabling anyone to eat crap and still be vegan. Thoughtful nutrition will see you home. :-)

  • Barry Schifreen

    i went vegan in 2007 after reading dr. neal barnard’s new book on reversing diabetes.  he said to go ‘cold turkey’ for 3 weeks to see how you felt and how your blood sugar numbers changed.  i eliminated eggs and dairy and poultry and the little red meat & fish i ate.  i lost 5 pounds.  over the next 2 months i dropped another 20 pounds, just by a vegan diet.  i still have a bunch more weight to lose, but my blood sugar is near normal now.  i say i’m ‘95% vegan’ as i do cheat occasionally when eating out.  so i’d call myself an overweight vegan.

  • Jacks

    Weight gain is more about amount of calories consumed, than whether the calories are from meat or veg. Vegans tend to be quite self disciplined, it goes with the territory, they restrict themselves rather than just satisfying their basic appetites. To my mind that is why there is a difference in BMIs amongst the groups.

    • Ana

      I know this comment was written several months ago, but I feel compelled to respond. I am a vegan who eats a lot of high fat plant foods: nuts, seeds and avocados, all in the same day. I never worry about calories or portion size, and I am at my ideal weight.. I don’t credit self-discipline at all. I’m just making better choices about where I get my fats and the type of foods I eat (yes, plants!). When I ate meat (many moons ago), I was constantly fighting the battle of the bulge. No matter what I tried — cutting back, counting calories — nothing helped. I would watch the pounds creep back like clockwork. Now I don’t even have to think about it. I just stick to a plant-based diet, and my body takes care of the rest. I am more slender, healthier and much happier. Yet, I still lack self-discipline. Go figure.

      • Nicki

        I am also a vegan (for 2 years) who eats high fat plant foods as well- and anything else I want to eat. Compared to my previous non-vegan diet I now eat a greater variety of foods and feel very liberated and excited about eating, not restricted in anyway. I have no desire to eat animal products and would definitely disagree with the point about not satisfying my basic appetite. I eat however much I want, without restrictions and I still weight the same amount that I did 10 years ago in high school.

        • smartgirl

          Yep, me too! Vegan a year & a half now, it’s so nice to not have to be “disciplined” (as I always had to be when I ate dairy & a little chicken & fish). I went vegan for the animals, but the tremendous improvement in health & naturally keeping weight off has been a wonderful bonus! Vegan food is just healthier in general. As long as you don’t resort to eating potato chips all day long, you can still have your treats & “junk” once in awhile with no need to worry about weight gain… just one of the MANY benefits of going vegan! :)

  • Randy Kreill

    Great video… I just found this one, but I went on a 100% vegan diet in early Dec. 2010, about the time this video came out. Since then, I’ve run 50 miles and completed a full iron distance triathlon workout on my 50th birthday. Worth noting… it’s been over 7 years since I did a ten day master cleanse fast and cut way back on dairy, and I’ve not been sick even once since then. No need to see the doctor, no antibiotics in that time. Weight management has been far easier on the all vegan diet started in Dec. 2010. I’ve finally ditched the cholesterol medication as well of course.

  • Robin Petersson

    What about people on Atkins-like diets?

    • Don Forrester MD

      The people on the Atkins-like diet are actually sicker when all factors considered… more diabetes, higher cholesterol. For more information you can see… or read Dr. Greger’s book, Carbophobia. The low carb diet is not consistent with our anatomy or physiology as hind-gut fermenting herbivores who have evolved to eat starch with more amylase genes and a 40% larger small intestine than our great ape relatives. Eat consistent with your design and you will be healthier. A varied Whole Food plant based diet centered on starches plus Vitamin B12.

  • Mike Quinoa

    I love the comedic element in your delivery, Dr. Greger. That “lazy vegans” quip just cracked me up.

  • Captain Michael

    Can you please show me that humans are herbivorous, Thanks doc :)

  • Kat

    Dear Dr. Greger,

    I would really appreciate if I could ask a few questions for a school essay. My topic is ‘Is the vegan diet healthy?” I would love your opinion!

    1. Are you vegan/vegetarian? If so, why?

    2. What are the negative affects of consuming eggs?

    3. Do you believe supplementing is necessary on a vegan lifestyle?

    4. Can eating too many vegetables or fruits be harmful?

    Thank you so much for your time, I hope to receive a respond.



    • Toxins

      Here is a write up on eggs.

      Eggs are considered good sources of lutein and omega 3 and an excellent source of protein. For these reasons, they are considered health foods. I am going to present the real science behind eggs showing that this is false. Firstly, chickens only have lutein due to the fact that they have a varietized feed, these nutrients are not inherent of eggs. A spoonful of spinach has as much lutein as 9 eggs. We cannot really consider eggs an appropriate source of this nutrient. As for protein, all whole foods are complete sources of protein so this statement to its benefits is insignificant. Energy needs satisfy energy expenditures which is equivalent to protein needs. As long as you eat whole plant foods when your hungry till your full, then your getting enough protein.

      Regarding Omega 3, current levels of omega 3 in eggs are highly inadequate and one must consume around 30 eggs to reach an acceptable level of omega 3 for the day. A male needs around 1.6 grams of omega 3 per day, a female needs around 1.1 grams a day. Omega 3 processes to EPA which is also processed to DHA, which is highly anti inflammatory. Omega 6 processes down to arachadonic acid which is highly inflammatory. The fact that eggs are the top source of arachadonic acid nulls and voids benefits received from the omega 3 in the egg itself. High intake of arachadonic acid is linked to autoimmune diseases such as rheumatoid arthritis, ulcerative colitis, as well as a clear link with cancer development.

      The Harvard physicians study followed 20,000 doctors for 20 years and those that ate just one egg a day had significant increase in all cause mortality.

      In fact, David Spence, director of stroke prevention/atherosclerosis research center and one of the worlds leading stroke experts, said that based on the latest research, you can eat all the eggs you want IF your dying of a terminal illness. Eggs are not considered health promoting nutritionally speaking.

      Eggs have been linked with heart failure

      As well as type 2 diabetes.

      Furthermore, in the Canadian Journal of Cardiology, David Spence, David Jenkins (the inventor of the glycemic index) and Jean Davignon (director of atherosclerosis research group) posted a review on eggs claiming that the egg industry has been downplaying the health risks of eggs through misleading advertisements. As soon as you eat one egg, you expose your body to several hours worth of oxidative stress, inflammation of ones arteries, endothelieum impairment (what keeps you blood running smoothly) and increases the susceptibility of LDL cholesterol to oxidize (beginning stages of heart disease).

      The egg industry has claimed that cholesterol from eggs is not important and does not raise cholesterol levels. The fundamental flaw in the study the egg industry has used to make this claim is that they measured FASTING lipid levels at night and not levels through out the day after egg consumption. “Diet is not all about fasting lipids; it is mainly about the three-quarters of the day that we are in the nonfasting state. Fasting lipids can be thought of as a baseline; they show what the endothelium was exposed to for the last few hours of the night.”

      A single egg yolk contains approximately 215 to 275 mg of cholesterol. A safe upper limit can be capped at 200 mg if one is looking to prevent heart disease. One egg far exceeds this daily upper limit.

      In regards to egg whites, although true they are a good source of protein, this is possibly the only positive statement that can be made of it. Here is some evidence of a major component of egg whites, Methionine, possibly causing human harm.

      1. Egg whites are high in the amino Acid Methionine. Rice has 14 times less of this amino acid and beans 7 time less. When one consumes Methionine in a large quantity (like that found in egg whites), it is broken down into sulfuric compounds. these sulfuric compounds are buffered by the calcium of the bones. the result, over time, is osteoporosis and kidney stones.

      2. Cancer cell metabolism is dependent upon methionine being present in the diet; whereas normal cells can grow on a methionine-free

      diet feeding off other sulfur-containing amino acids.

      3. Insulin like growth factor is raised significantly by Methionine. raised levels of IGF-1 = accelerated aging/tumor promotion.

      4. Sulfur from Methionine is known to be toxic to the tissues of the intestine, and to have harmful effects on the human colon, even at low levels, possibly causing ulcerative colitis.

      The only supplements Dr. Greger recommends are vitamin b12 and vitamin D.
      You can have too much vegetables in some cases, but not practically. After consuming 100 cups of broccoli in a day DNA damage has been shown to occur, but who would eat this amount in a day?

  • Patrik Floding

    Sure, the vegans will be exercising less, due to low energy levels. They will be slim due to starving. Simples.

    • Evy

      you cannot be serious :D

  • Liz

    I love this website, but something is not right with this study. I know people who have lost weight by increasing their meat consumption.

    • Toxins

      They did not lose weight by increasing meat, the real culprit was the cutting in calories. Those on an atkins style diet also lose weight through water.

  • Charles Peden

    This is a cruel video. I haven’t lost a single pound from eating vegan since the beginning of the year. It brought my cholesterol down from 260 to 164, so now I’m the 290 lb. guy who has the lowest cholesterol in the office. I’ve also recently started eating low salt about a month ago. That hasn’t affected my weight, either.

    Switching to vegan was easy. But reducing my salt intake took the enjoyment out of eating. Now I have the depressing prospect of having to reduce sugar and fat, too. The “healthier” I eat, the less I enjoy food. I don’t blame people for running to McDonald’s.

    I stick with it because I work part-time in a nursing home and I see the effects of stroke and rheumatoid arthritis. As scary as those are, I seem to be the only staff member who is actually making a dietary change to try and prevent that from happening to myself. My job is also physically demanding which has not had any effect on weight loss, either.

    If I still haven’t talked you out of this way of eating, realize that I can’t just pop in to one of the dozens of fast food restaurants near one of my jobs. I work over 60 hours a week and don’t have much time to devote to cooking, so convenience is certainly a premium. But I can’t just run and get something to eat like everybody else I work with. And I don’t look forward to meals anyway because my food is not compelling. I just eat to stop being hungry.

    It is alleged that this way of eating will get better over time, but that time is not now. This is not enjoyable. This is healthy food, but not delicious food. If this food causes weight loss, I have yet to see any personal evidence of that. Obesity is not cured by simply eating a vegan diet. I hope it eventually will prove to be effective, but nothing so far.

    • Anna

      try reading 80-10-10 by Dr. Douglas Graham its a very enlightening book. Fruit is fast food made by nature!:) good luck

    • Toxins

      There is a big difference between vegan and whole foods plant based. A vegan diet means lack of animal products, and that, in itself, does not guarantee you health. A vegan diet can include white bread, mock meats, chips, sodas, free oils, etc. A vegan diet can be all junk food and still be vegan. The key is to eat whole, minimal processed plant foods.

    • fineartmarcella

      charles you can still eat wrong as a vegan. I weighed 300 pounds as a vegan…try Raw, my lifetime hunger disappeared (you know the hunger you feel even after eating a large pizza), I lost 65 pounds easily, and yet to exercise, eat all the fruits you want all day and do eat ALOT of fruits so you get in your calories, then end your day with a 1 pound veggie lovers salad with homemade drsg like juice with added spices or something like that. Make sure you have plenty of fruits around so you never run out, and if you are hungry eat 3 apples not one, or 3 bananas, make sure you satisfy yourself, not just nibble a snack, I really don’t have meal times, I eat when I am hungry, the 80-10-10 book is helpful to learn from. I fix a lunch bag full of fruits and veggies for work and people get jealous! haha Remember when you go raw, don’t try to eat little bits, you are no longer watching calories, you are eating like you were ‘meant’ to eat, thats why it becomes natural, you feel better, and you drop weight!

  • Lauren Perry

    Is there any discussion in the article regarding other measurements of health besides Type 2 Diabetes (especially since the majority of the scientific community now knows better than to use BMI as an indicator of health or “ideal weight”)?

    I definitely agree with the notion that vegans are generally more health conscious and that it never accounted for in these studies. I think it’s also worth noting that, the more restrictive your diet is by choice, the more disciplined you are able to be about your eating. Someone who, perhaps, wants to be vegan but struggles with temptation is also going to be someone who struggles more to stay away from unhealthy foods in general.

    It’s also true that a lot of people take on a vegan diet because it so restricts what they can eat and restricts the majority of junk food products. Becoming a vegan with health in mind is just like adopting any other health-based dietary changes, and one would expect to see similar results in any shift toward healthy living. I would also expect to see significant differences between those who are ethical vegans (no animal products or testing at all) and those who have simply adopted a plant based diet (veganism for health reasons alone).

    • fineartmarcella

      Just to add, I don’t know that many folks who live a vegan lifestyle just for their health, they usually get in under ethical reasons, then, as they progress, and get ‘better’ at it, they find the health benefits of a vegan lifestyle. I actually do not know a single vegan that is in to exercise or aerobics, most of us just enjoy life and our animals, once you feel the difference in your body and your health you become a health-minded vegan also.

      As a vegetarian, I ate poorly really, lots of processed foods, lots of cheese flavored fat (as my doctor calls it) and was quite obese, losing nothing after leaving the flesh eating world.

      When I became Vegan, (no cheese anymore) I lost about 30-40 pounds from the lack of fat.

      But when I became RAW Vegan, I lost, well so far, 65 pounds, I’m no longer ‘hungry’ all the time, I am satisfied and so much healthier! I still sit on the computer or TV, not quite exercising, but no longer a prediabetic, my total cholesterol is 141 (without statins), well, and all the other labs are great too!

  • Vegetarian Protein

    Im vegan and I do eat a lot of wheat based products. Although I dont eat bread as it tends to make me gain weight I eat lightly cooked pasta made with various things everyday. I would say as I vegan my diet has become based on lower GI wheat based products and an avoidance of bread and rice. I dont get that much exercise these days and tend to be in pretty good shape most of the year round. I would guess my BMI to be ideal and I am also very strong as on the times I have been training I find I am able to gain modest lean muscle mass quite easily without any animal products whatever. I also drink a lot of soy-milk. So basically lots of fresh fruit and vegetables, pasta and soy milk is my diet. Pasta would be the basis.

    • Bénédikte

      I can send you an web side to find some amazing vegan protein if you want. They are made in Canada and get the biological certification AB in France and iso 9000 value. With 98,2% of assimilation with 90% of concentration and without : gluten, OGM, milk, nuts and soya. I mixed them in the morning with fruit vegetable and cereal milk like rice, or spelt flour and hazelnut juice etc…

  • Janice Hanna

    I curious about levels of vegans in the study and I bet the Raw Vegans are the leanest!