Living Longer by Reducing Leucine Intake

How What We Eat (And Don’t Eat) Impacts How We Age

Many studies have shown that calorie restriction, without malnutrition, can increase lifespan and lower the risk of age-related diseases, such as cancer.

However, for many people, calorie restriction clearly has its drawbacks. In the classic Minnesota Starvation Study, many of the volunteers suffered a preoccupation with food, constant hunger, binge eating, and lots of emotional and psychological issues. Even researchers who study caloric restriction rarely practice it. There’s got to be a better way to suppress the aging engine enzyme, TOR (see Why Do We Age? for more on TOR).

That’s why researchers were so excited about rapamycin, a drug that inhibits TOR, thinking it could be caloric restriction in a pill. But like any drug, it a long list of potentially serious side effects. There’s got to be a better way.

The breakthrough came when scientists discovered that the benefits of dietary restriction may be coming not from restricting calories, but from restricting protein intake (See my video Caloric Restriction vs. Animal Protein Restriction). If we look at the first comprehensive, comparative meta-analysis of dietary restriction, “the proportion of protein intake was more important for life extension than the degree of caloric restriction.” In fact, just “reducing protein without any changes in calorie level have been shown to have similar effects as caloric restriction.”

That’s good news. Protein restriction is much less difficult to maintain than dietary restriction, and it may even be more powerful because it suppresses both TOR and IGF-1, the two pathways thought responsible for the dramatic longevity and health benefits of caloric restriction.

Some proteins are worse than others. One amino acid in particular, leucine, appears to exert the greatest effect on TOR. In fact, just cutting down on leucine may be nearly as effective as cutting down on all protein. Where is leucine found? Predominantly animal foods: eggs, dairy, and meat (including chicken and fish). Plant foods, such as fruits, vegetables, grains, and beans, have much less.

“In general, lower leucine levels are only reached by restriction of animal proteins.” To reach the leucine intake provided by dairy or meat, we’d have to eat nine pounds of cabbage—about four big heads—or 100 apples. These calculations exemplify the extreme differences in leucine amounts provided by a conventional diet in comparison to a plant-based diet. The functional role of leucine in regulating TOR activity may help explain the extraordinary results reported in the Cornell-Oxford-China Study, “since quasi-vegan diets of modest protein content tend to be relatively low in leucine.”

This may also help explain the longevity of populations like the Okinawa Japanese, who have about half our mortality rate. The traditional Okinawan diet is only about 10% protein, and practically no cholesterol, because they ate almost exclusively plants. Less than one percent of their diet was fish, meat, eggs, and dairy – the equivalent of one serving of meat a month and one egg every two months. Their longevity is surpassed only by vegetarian Adventists in California, who have perhaps the highest life expectancy of any formally studied population in history.

This reminds me of the study I profiled in The Benefits of Caloric Restriction Without the Actual Restricting.

Methionine is another amino acid that may be associated with aging. See Methionine Restriction as a Life Extension Strategy to find out which foods to avoid in that case. Both leucine and methionine content may be additional reasons why Plant Protein is Preferable.

Other reasons why those eating plant-based diets may live longer:

 This all may help explain the results of Harvard’s Meat and Mortality Studies.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 – 2015 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: hslo / Flickr

  • Julie

    What are the practical protein recommendations for us to follow? How much protein should we eat daily to not activate TOR, but to fulfill our nutritional needs? Can we eat unlimited vegetable protein since it is low in leucine and methionine?

    • Joseph Gonzales R.D.

      Here are some protein recommendations. In the last link of this blog Dr. Greger mentions how plant protein is preferable. It’s hard to say exactly how much protein to restrict to suppress TOR. The recommendations for protein intake vary from 10-35% of total calories. The tradition Okinawan diet is only about 10% protein, so perhaps the lower end of that range (10-35%) is preferred.

    • Charzie

      Maybe this is a stretch, but I was thinking that if nature provides growing, developing infants with an ideal formula in mother’s milk, maybe our nutritional guidelines should be based close to that proven ratio, so I investigated it and was VERY surprised by what I found…(remember it is mostly water.)
      Mature human milk contains 3%–5% fat, 0.8%–0.9% protein, 6.9%–7.2% carbohydrate calculated as lactose, and 0.2% mineral constituents expressed as ash. Its energy content is 60–75 kcal/100 ml.

      • Julie

        Thanks, Charzie. Since the values you gave are by weight, I converted them to percent of calories. Human breast milk contains ~5% protein, 54% fat and 41% carbohydrate. Pretty surprising that protein is so low. I’m guessing that the growing infant needs lots of healthy fats for brain development, that adults probably don’t.

        • Charzie

          Thanks so much Julie, a math whiz I am not, but thought it was interesting with all the questions about protein we get grilled about. I agree about the brain growth and the fat%… plus it is very easy to digest and utilize and comes with all kinds of amazing benefits, including even pro and pre biotics. Once past nursing age I’m sure the ratios shift to less fat and more carbs, (but cow’s milk is never an acceptable substitute for infants for numerous reasons.) If adults ingest that much fat, well…I had diabetes and it was all about the fat because dropping it to >10% made it go away before I even lost much weight!

    • Darryl

      The amino acid in plant based diets that is likely to be limiting is lysine (not to be confused with leucine). Consume enough lysine in a varied plant based diet, and you’re likely to have adequate amounts of all the other essential amino acids.

      Beans, greens and potatoes have more lysine relative to their leucine + methionine content than other higher protein plant foods: potatoes (0.83), legumes, greens (0.7), nuts & seeds (0.5) grains (0.3), so even though the leucine content of beans may seem high in absolute terms, they still offer the best balance of adequate lysine without excess leucine and methionine. Food group leaders by this measure include cauliflower (1.72), split peas and lentils (0.86), pumpkin seeds (0.70), buckwheat & quinoa (0.67).

      The more I look at potatoes, the more they appear like the ideal staple. Compare the percent of amino acid requirements for a 60 kg adult in 2000 kcal of these foods:

      potato skim milk whole eggs
      His 147% 1000% 720%
      Iso 141% 853% 782%
      Leu 106% 802% 649%
      Lys 151% 921% 709%
      Met+Cys 159% 712% 1013%
      Phe+Tyr 220% 1353% 1099%
      Thr 180% 941% 864%
      Try 227% 1053% 973%
      Val 168% 833% 769%

      fiber 203% 0% 0%

      One could eat nothing but potatoes and get adequate but not excessive amounts of every essential amino acid (and be well ahead on the fiber and potassium fronts, as well).

      • Julie

        Thanks, Darryl. I eat lots of beans, greens and potatoes so I guess I’m all set on amino acids.

      • Filipe Coimbra

        Darryl, I’m curious, What is your area of expertise? Thanks for all your amazing insights here on NF forum.

        • Darryl

          I have an undergraduate degree in biochemistry but have worked most recently in computer science. I just discovered (largely inspired by Dr. Greger) a fascination with the underreported sides of nutritional science, and in particular its relation to chronic and aging-related disease, and so for the past two years, on average I download 3-5 papers daily from the primary literature, and when I find time read a couple.

          • Filipe Coimbra

            Cool! Biochemistry is definitely an great foundation for the field of Nutrition. So, you are in the vanguard of two fields that can change the world (nutrition and technology). Amazing! Keep going!

      • What do you make of the Glycemic Load of potatoes? According to nutritiondata, the GL of a large baked russet is 29. See

        • Darryl

          There’s no question potatoes have a pretty high glycemic index, and hence present an issue for those who already have insulin resistance or diabetes. There’s perhaps a saving grace in that a substantial fraction of their starch will gelatinise/anneal into digestion resistant starch if baked and allowed to cool for a few hours.

          Sweet potatoes are nutritionally superior in most respects, with 2000 kcal complete in all essential nutrients for a 60 kg adult except B9, K, Se, and maybe EFAs (some greens and a Brazil nut would fix this), and moreover have a glycemic index about half that of potatoes. I wish that I enjoyed their taste more (I find them too sweet in most dishes).

          • Thea

            Darryl: Thanks for this post. I like how you put all that information together. Very helpful.

            re: “…I wish that I enjoyed their taste more.”
            You may feel that way about all sweet potatoes, but I thought I would share that I find that the sweet potatoes that are white or purple-fleshed are a lot less sweet than the orange-fleshed sweet potatoes. And I have had great success in substituting those types/colors of sweet potatoes in dishes without problem. Sometimes I even like the sweet ones better in dishes that call for regular potatoes.

            I just wanted to share because I generally do not like the orange-fleshed sweet potatoes and was happy to discover a few years ago that the other colors actually taste different to me. Plus they have a better texture than the orange ones I think.

            Just sharing.

        • dorange

          Adding fiber or fat will low the glycemic load of potatoes – and of any food, so to speak.

      • And what about the phytonutrients in potatoes?

  • Chris

    I have been following a plant based diet for the last 2 years, and before that I used to intermittently fast every 3 months to lower my IGF-1 and mTOR levels, which I get measured every few months. Since following your site the last few months and reading the very interesting article I have increased my intake of black beans and other legumes to benefit from their potential. However this article about leucine seems contradictory to that of increasing bean intake, such as black beans, to improve long appear to contain a reasonable quantity of leucine.

    • Joseph Gonzales R.D.

      Leucine is still an essential amino acid so humans require dietary sources. The average 140 pound adult needs roughly 2673 mg per day. Also, I feel if we spend too much time worrying about one essential amino acid we forget about the massive amount of iron, zinc, fiber, antioxidants and phytochemicals in black beans. They are such a healthful food that I would hate to see folks limit them based off their higher leucine content.

      • Chris

        That was my thinking as well, I will see how my increased consumption in black beans has affected my IGF-1 levels next week. Keep you posted ;-))

        • dorange

          Please, Chris – really interested to know what have worked best in lowering IGF-1 levels!

  • Dommy

    What is the current thinking on resveratrol and aging?

    • Plantstrongdoc M.D.

      The primary target for resveratrol is activation of SIRT 1. There are a lot of data “out there” regarding resveratrol – some data suggest reduced risk for cardiovascular disease, diabetes, some neurological diseases and various cancers. Probably no effect on maximum lifespan in humans (as opposed to CR), but probably effect on health span in some subgroups. Resveratrol is not the fountain of youth and resveratrol can in no way outweigh a poor diet. Regarding health there are no alternative to a diet as near as possible to WFPB diet.

    • Joseph Gonzales R.D.

      Plantstrongdoc gave the link to a study in another blog I’ll post it here, if interested. Thanks, Dommy!

      • Plantstrongdoc M.D.

        As you know resveratrol is just one out af several polyphenols that have been extensively studied – others are quercetin, genistein, catechin and others – and data suggests considerable health benefits. Resveratrol is probably famous because it is present in red wine – and hence a very studied compound. Others are also “potent compounds” – and the “secret” behind the enormous health benefits from a plant based diet is probably a synergistic effect from all the polyphenols and it can of course not just be reduced to resveratrol or quercetin – but a very interesting field.

      • Dommy

        This is not news to NF readers but here’s the latest study correlating nut consumption and longevity:
        “Nuts and peanuts, but not peanut butter, may protect against death from cancer, heart disease, respiratory disease, and other major causes”

        Thank you, Joseph.

        • Joseph Gonzales R.D.

          Awesome. Thank you!

  • alexih

    Just curious, what does the photo have to do with this topic. Looks like a McDonald’s fish sandwich.

    • I was trying to contrast caloric restriction versus animal protein restriction–quantity of food versus quality of food. Sounds like it didn’t come across. If you can find a better Creative Commons pic I’ll swap it out!

      • alexih

        not an easy task. how about this:

      • alexih

        I will some more for a photo. The other thing I don’t get about the picture above is the shoe lace or whatever that is. And is that photo supposed to be showing both animal protein and plant protein? I don’t see that. Not an important part of this great article, just something that made me wonder.

  • Michael

    Dr. Greger,

    I posted the below comment on your Calorie Restriction vs. Animal Protein Restriction video:

    I’m glad you wrote more about this topic, but I’d love for you to discuss more about the shared connection mTOR has with aging and muscle protein synthesis. The studies I reference below discuss how mTOR is the pathway that leucine uses to signal muscle protein synthesis. For plant-based people who want to build lean muscle mass, I ask again, are these goals (longevity vs. building lean muscle mass) fundamentally opposed goals since they both seem to occur through the same amino acid (leucine) acting on the same signaling pathway (mTOR)? Or, hypothetically, could is be a case of plant vs. animal sources of protein similar to your dozen videos on plant vs. meat nitrates (see more in my original comment below).

    Thanks for your consideration.

    It seems that both signaling muscle protein synthesis (MPS) and aging prematurely (as discussed in this and previous video) involve the leucine/mTOR connection. Do you think, or is there research, that long life and building muscle mass are fundamentally opposed goals based on how our body is designed? Also, do you think, or is there research, that the mTOR theory of aging and leucine acting as a trigger could be meat/animal-protein specific? In other words, could eating leucine-rich plant foods in order to signal MPS still provide longevity benefits as well as muscle-building benefits? Kind of similar to the whole nitrate/nitrite conundrum where plant-sourced nitrates (from beets and arugula) get metabolized in the stomach and re-sent to the mouth where, instead of becoming carcinogenic nitrosamines (as is what happens when you consume nitrates from meat), they become NO and increase our oxygen efficiency. This seems plausible to me since you’ve praised pumpkins seeds (which are relatively high in leucine) in some past videos: (… specifically the mineral content and serotonin boosting effect.

    Research papers describing MPS and leucine signaling:

    • Joseph Gonzales R.D.

      Hi Michael. I meant to give this to you earlier, thanks for the reminder! Here are a few position papers that discuss protein needs in athletes. 1) Nutrition and Athletic Performance and 2) Position of the American Dietetic Association and
      Dietitians of Canada: Vegetarian diets
      and a more recent version, here. The exact amount of protein for athletes to maintain and build muscle mass without stimulating TOR is very hard to determine. I do not think any study has been conducted to know for certain. Again, I think you’re onto something, as even though pumpkin seeds may be higher in leucine they provide fiber, antioxidants, and other phytochemicals that eggs and chicken do not.

      • David Johnson

        I think this is an important question. Sarcopenia is a serious concern for older people (like me) as it can lead to falls, fractures, diabetes, or otherwise restrict the quality of one’s life. I find it sad to see older people who are frail due to sarcopenia, since it is unnecessary. It is certainly significantly more difficult to build lean muscle when one is over 65, at least that’s my personal experience. Because of this, I think it wise to pay attention to muscle mass when one is younger (wish I had paid more attention) – it’s much easier to maintain it than create when one is a senior. Living longer does not necessarily mean a better quality of life. Picking out one aspect of health (not stimulating TOR) and then overly restricting protein to achieve that one goal could well backfire way down the road.

        Here’s the url for a short and inconclusive overview of some studies and issue from Harvard:

        • Joseph Gonzales R.D.

          Great point, for those over 65 more protein is required. The low end of protein recommendations are between 0.8-0.9g/kg for adults. After 65 years old, based on this study, I would suggest bumping up these recommendations.

          • Jason

            I also saw that study when was published several months ago. I recall they categorized less than 10% of calories from protein ‘low protein’; between 10 and 20% ‘moderate protein’; and over 20% protein ‘high protein’ diets. Those under 65 did better on low and moderate protein diets, but those over 65 did better on high protein diets insofar as cancer was concerned…but they had much more diabetes. So it’s a tough call to recommend a high protein diet even for seniors. I guess it really depends on how many calories you take in.

            For a typical 80 kg. (175 lb.) man, a moderate recommendation would be 1 gram of protein X 80, or 80 grams/day. Say this guy eats 2,400 calories–which a lot of active men do. 80 grams of protein is about 320 calories, so he should be aiming for 320/2,400 or 12.5% of calories from protein. That’s low-moderate. To be considered ‘high protein’, he’d have to consume over 480 protein calories, or 120 grams. That’s 50% over the moderate recommendation of 1 gram per kg. of body weight, and nearly twice the RDA set by official health organizations (0.8 grams per Kg.).

            I just doubt that getting 1.5 grams/Kg. is a good idea when so many seniors suffer from reduced kidney function (about a third of those > 60 have Stage 3 CKD). But maybe vegetable sourced protein is OK?

          • Joseph Gonzales R.D.

            Thanks for sharing your thoughts. I think it’s noteworthy that the high protein group eating animal protein in this study was responsible for 75% increased overall mortality and a 4-fold increase in risk of dying from cancer, compared with higher protein intake from plant sources. The increased risk of diabetes mortality seemed strange. I wonder if they controlled for animal protein? I would agree that 1.0g/kg is probably better than 1.5g/kg, but keep in mind protein recommendations vary based on individual needs.

          • David Johnson

            Thanks for the reply. The study you cite is very interesting, particularly to me the part about older people having more difficulty producing sufficient IGF-1 for good health (not sure what that level might be).

            This underscores the fact that nutrition and health is a complicated topic! More of something is not necesssarily better, but the same can be said for less.

        • Gary

          I share your concern about getting enough protein to just maintain strength and muscle mass at 60 this yr. I’ve been pretty much vegan for 2 yrs and lost 15 lbs down to 150 at 6ft tall.
          I measure my strength every month by how many pushups, situps, pullups, and dumbbell presses I can do.
          I didn’t want to become the typical skinny, weak vegan example. Out of 21 meals I include one with fish.

          I recently upped my protein to maybe 50 or 60g from a low in the 30-40 area as it was a struggle to keep up the reps and no muscle mass gains. All downhill into our 80s…grr
          So I’ll see if that makes a difference.
          A vegan muscle building site recommends 150g of protein for a 150lb man. I’m not about to do that.

          • rob

            I am 81 and fair health but nothing serious, yet. I read this about Leucine.
            “Excess leucine may be a cause of pellagra, whose main symptoms are “the four D’s”: diarrhea, dermatitis, dementia and death,[10] though the relationship is unclear”
            I have considered adding protein powder to my morning smoothies. Doesn’t seem like a good idea. I don’t work out except a short walk a few times a week but watching my diet and food I eat. I am 5ft 7in and 154 lb.

          • Gary

            Sounds like you’re doing pretty darn good at 81 rob.
            I guess I raised the bar pretty high for myself having the superman Jack LaLanne for a role
            He was in great shape all the way to 97 by working out every morning at 5 and then 6am for more than an hr. He ate alot of fruit and salad, but also ate egg whites and salmon every day. I’m trying to avoid doing that.

          • David Johnson

            I am wondering why your protein intake is so low compared to mine. According to Chron-O-Meter, a typical days worth of food on my diet provides about 75g of protein. Since I am only 5’7″, small framed and 124 pounds (56 kg), I doubt my difficulty building muscle is protein related since I’m getting about 1.3g/kg/day, which I’ve seen recommended for seniors (I’m 68). When I used to do a lot of weight lifting (which I only started in my early 50s), I was a long time vegetarian but ate a lot of dairy, including whey protein, but quit heavy lifting and focused on aerobic conditioning about 3-4 years ago, and about a year ago switched from long time vegetarian to vegan. The combined change dropped my weight from about 142 to 124. I am happy about losing fat but I clearly also lost a lot of muscle as I am not nearly as strong these days. I am trying hard to regain some of that muscle but it is a struggle. I have read that for seniors, increasing volume of resistance exercise is needed to adequately stimulate muscle growth, but don’t have the references handy. Keep up the good fight!

          • Gary

            I guess I get too full eating fruit, potato and salad and haven’t paid much attention to protein.
            I don’t use protein powder, just added beans 3 times a day, plus quinoa and sweet peas.
            I did some exercise most of my life. I guess I miss the good old days at age 30 when gaining strength and size was easy and felt strong before a workout.
            I haven’t really lost any muscle at 60 and I’d like to keep it that way. But I am finding it harder to make any gains.

          • Gary

            Well after 2 wks of increasing my plant protein and a bit of fat from nuts I’m pleased with the results in both strength and mass. Also feel stronger and more “puffed up” in the legs, back and arms. That’s a big plus because it helps make the wrinkles in the arms and even under my eyes decrease.
            I may not have been eating enough fat along with enough protein.
            I also gained 3 lbs, to 153 assuming it is muscle. So it’s not all downhill (getting weaker) from 60 to 80 even on a plant based diet.

            Sitting 50 lb overhead press increased from 22 to 31 My weakest event.
            Squats with 35 lb from 32 to 42 reps, 5 sets
            pull-ups 5 to 7
            chin-ups 7 to 8
            sit-ups still 80 in 2 min.

      • David Johnson

        Now I am wondering whether significantly increased amounts of leucine post strenuous exercise, e.g. from heavy weight lifting, might not have the negative effects it would otherwise have. The last article cited by Michael got me thinking about this.

        • Joseph Gonzales R.D.

          Leucine is still an essential amino acid. I think the idea is that consuming too much may be problematic, but lower amounts are fine and still necessary. I suggest shooting for the low end of protein recommendations, but as we discussed bumping up needs after 65 years old.

  • perlis

    I am pretty sure the calorie-restriction-longevity idea has been discredited for humans (even though it holds for rats and mice). Not that it is central to your posting. But it might be best not to feature that idea since it seems to fly in the face of evidence (for humans and at least some other primates).

    • John

      Instead of just saying that, perlis, can you show us a link to something that goes against the evidence that the doctor stated.

    • The Vegetarian Site

      Has CR been discredited? There are contradictory primate studies on this issue, both of which have some serious issues. As for the human studies, none is long enough to make a proper determination of lifespan extension, but most biomarkers look positive for CR. One thing that is quite clear, is that equilibrium species (such as humans) are not going to see the 30-40% maximal lifespan increases with CR that have been shown for mice. The traditional long-lived Okinawans are perhaps the best example of moderate CR combined with low protein intake, but there are several other lifestyle factors that likely contribute as well.

  • charles grashow

    vegetarian Adventists in California study you linked to


    Choices regarding diet, exercise, cigarette smoking, body weight, and hormone replacement therapy, in combination, appear to change life expectancy by many years.

    SO – how can you claim that diet ALONE is responsible for the increase in life expectancy??

    • Maureen Okun

      This is only a partial answer to your question, but the video at this link shows evidence that the plant-based diet has a protective effect that goes beyond that of other healthy choices. This is not at all to say that exercising, not smoking, and so on aren’t very important to one’s health, but diet really does seem to be the most important factor of all. I believe that there are other videos here related to this topic that I didn’t have time to browse around for but that I vaguely remember.

    • Maureen Okun

      This is only a partial answer to your question, but the video at this link shows evidence that the plant-based diet has a protective effect that goes beyond that of other healthy choices. This is not at all to say that exercising, not smoking, and so on aren’t very important to one’s health, but diet really does seem to be the most important factor of all. I believe that there are other videos here related to this topic that I didn’t have time to browse around for but that I vaguely remember.

    • Joseph Gonzales R.D.

      You may want to check out the papers on the Adventist Health Study-2 cohort. There are so many studies within this cohort that finds diet is the factor responsible for lower rates of diabetes, some cancers, lower body weights, etc. All of these videos on Adventist may also help explain.

    • 2tsaybow

      Why, if you believe in a paleo based diet, do you spend so much time going to alternative sites to argue with them? I am not trying to be hostile or anything; I am just curious.

      I find the scientific evidence offered by Dr. Greger very helpful for my lifestyle choices. What do you find here that supports your day to day life?


  • Sherry Patterson

    Dr. Greger,

    I have a question. I have been following a low-fat, whole-food, plant-based lifestyle for 4 years. I am now a consultant for the lifestyle and have my own business: Attainable Wellness. I have also been using Liquid Aminos for seasoning on a daily basis. Liquid Aminos have leucine and methionine as well as other amino acids that are derived from soy beans. After reading your article I wonder if Liquid Aminos are healthy?

    Could you share your opinion? I don’t want to lead myself or my clients astray.

    Thank you so much,

    Sherry Patterson

    Attainable Wellness

    • Joseph Gonzales R.D.

      An oldie but useful. Is MSG Bad For You?
      . Keep in mind there is less than a half a gram of protein in liquid aminos. I am not advocating it, but if you like the taste I see no reason to avoid based on the animo acids content.

  • Spud

    It might be interesting to note that soy protein isolates are VERY high in leucine ( …but as previously noted ( 3-5 servings of (WHOLE) soy is better for you. Looks like those transitional “Vegan Faux-meats” based on TVP may not be a “safe” alternative afterall.

  • I Wonder if Leucine from Plant Sources is Any Different Than Leucine from Animal Sources?… Some of the Top Foods with HIGH Leucine Levels ARE from Plants: Soy Protein Isolate, Spirulina and Watercress! :-(

    • Joseph Gonzales R.D.

      Good points! Please see my comments below in this thread. It may help explain your two recent questions. Thanks.

    • guest

      There’re only two types of leucine: L-leucine and D-leucine. Plants and animals contain only L-leucine, so the leucine vegans get from food and that omnivorous do are one and the same: L-leucine.

  • Bummer… soybeans, lentils, peanuts, almonds and walnuts are are high in leucine as well. :-(

  • sherry7701

    What are your thoughts on Liquid Aminos as a seasoning. They contain leucine and methionine derived from soy beans.

    • Joseph Gonzales R.D.

      Please see my comments below to Sherry. Thanks, unless this is Sherry from another account, in which case please see my reply to your original comment :-)

  • Kitsy Hahn

    “To reach the leucine intake provided by dairy or meat, we’d have to eat
    nine pounds of cabbage—about four big heads—or 100 apples.”

    I’m just wondering if the nine pounds of cabbage would relate to, say, a cup of yogurt. — or maybe a half cup. Or three cups. In other words, how big a portion of animal protein are we talking?

    • Las

      According to, 9 lb of cooked green cabbage contains 1.7g of leucine. The same amount is contained in 1.3 cups of plain, lowfat yogurt.

  • artcomm

    I am 65 years old and my arms —the skin of my arms— has become ultra sensitive. I am a passionate vegan and I would never go back on this one; however, every single time I show what happens to my skin in my arms —that is the only part of my skin where it happens— they tell me immediately that the problem comes from not eating enough “animal protein”. Let me explain what happens: a little heavier pressure on the skin of my arms causes the capillary vessels to explode and bathe with blood a vast region. Eventually it all goes back to normal. My mother was NOT vega at all and she had the same weakness; so, it has to be some sort of genetical trend, or is it? What would the advice be?

    • Joseph Gonzales R.D.

      I’m not sure how animal protein would “fix” the problem. You could try and see if there is a difference? We have many videos on skin health. Protein, vitamins, and minerals are important for generating new growth of skin, hair and nails. So long as these nutrients are adequate I would expect proper growth. Have you seen a dermatologist? What did your doctor recommend?

    • Israel Navas Duran

      Did you check your bleeding, prothrombin, and coagulation times?

  • M Mitchell

    I see that soy foods and nuts and seeds, even beans are high in leucine. Should one avoid them too?

  • TS

    What is the leucine content of nuts and seeds. Should they be restricted.

  • Cecile

    I understand that some plan foods are high in methionine, like sesame seeds. Would you recommend limiting these foods? I eat a whole food plant-based diet since my breast cancer diagnosis and I was wondering if I should limit my consumption of tahini.

    • Good question, Cecile, and I see that nobody’s responded. In addition to methionine and leucine, other amino acids may be troublesome: arginine also appears to stimulate mTOR signaling and many cancers thrive on glutamine. As for sesame seeds, they also contain a fairly significant amount of copper, which stimulates angiogenesis. As a cancer survivor, I opt for following the precautionary principle–and have eliminated sesame seed paste. According to the nutritiondata website, chia seems to be a healthy alternative. Compared to other common seeds, it’s lower in glutamic acid and very low in methionine.

  • elsie blanche

    Speaking of the Okinawans, you profiled a study a ways back talking about the benefits of the sweet potato, as far as undigested proteins of S.P. having positive effect, but is there also a negative effect as far as undigested proteins circulating the body, causing immune or gut issues? I’ve always heard that undigested proteins can be a bad thing as well. Thoughts on this, Dr. G? Thanks.

    • David Johnson

      I am wondering which study you are referring to. One of the reasons I quit taking PPIs for acid reflux was the issue of undigested proteins causing allergies. So this sounds odd to me but I have not seen the video.

      • elsie blanche

        Dr. Greger did a video highlighting the benefits of sweet potatoes, and he said that parts of the sweet potato proteins remaining undigested are what created these said benefits. So yeah, for some folks maybe undigested proteins do not cause harm but I am wondering if this applies to the sweet potatoes as well.

  • M

    I got a little confused. Here Lucene shortens my life. but in every Bodybuilding guidebook it’s one of the essential aminos that every sportsman should take. Even they claim it is good that it activates mTor. I had read that 5-`10mg a day is essential to gain muscle. Where s the middle?

    • Joseph Gonzales R.D.

      Here are some protein recommendations. In the last link of this blog Dr. Greger mentions how plant protein is preferable. It’s hard to say exactly how much protein to restrict to suppress TOR. The recommendations for protein intake vary from 10-35% of total calories. The tradition Okinawan diet is only about 10% protein, so perhaps the lower end of that range (10-35%) is preferred. The low end of protein recommendations are between 0.8-0.9g/kg for adults. After 65 years old, based on this study I would suggest bumping up these recommendations. For athletes now we’re talking a new ballgame. I talk about that further down in the thread about protein needs, of course they can vary depending on individual needs.

  • Thea

    Don’t know if this will help anyone’s fears or not, but I looked up leucene amounts for 1 cup of a few foods that people might easily/naturally eat a cup of at one time — on the website :

    Chicken: 2827 mg
    Pinto Beans: 1308 mg
    Quinoa: 483 mg
    Brown Rice: 372 mg
    Broccoli: 230 mg

    So, even though beans are higher in leucine than say brocooli, beans still have *significantly* less leucine than say chicken. Given the abundance of evidence we have on the benefits of beans (check out:, I say, “Pass me some beans, please!”

    brown rice:

  • Greentara

    What about soy protein from tofu or tempeh? You mention vegetables and beans, but not soy products.

  • Jason Huang

    However, some other studies show that supplementing leucine extends lifespan in mice.

    Even though the results of the study, published in the
    journal Cell Metabolism, are based on animal studies, they
    hold a lot of promise especially in our efforts to keep old
    age at bay.

    In the study, Dr. Enzo Nisoli, of the University of Milan gave mice drinking water laced with
    three amino acids — leucine, isoleunic and valine. At the
    end of the study, the mice receiving the amino-acid cocktail
    extended their lifespan by 12 per cent compared to the
    control group receiving ordinary water.

  • BR

    Small typo: “it a long” should probably be “it has a long”

  • Noam Hadadi

    as an athlete i know that leucine is probably the most important amino acid for anabolic response, and proteins are as good s their leucine content, so if i want to be stronger and build muscle, dont i need plenty of leucine?

    • Darryl

      Alas, mTOR is responsible for some anabolism (and in the hypothalamus, satiety), but also suppresses catabolic processes like autophagy that confer protection against aging related diseases. There may be a fundamental downside to depending on leucine for anabolic response and weight loss.

      There is a bright side: while protein restricted animals live longer, and leucine related mTOR inhibition appears to account for some of this, most of the benefit of protein restriction is captured in experiments that just restrict methionine. Excess methionine appears harmful by an different mechanism, increasing mitochondrial membrane potential and ROS production.

      So, there’s the option of attempting to maximize benefits from higher leucine intake while minimizing excess methionine (and probably cysteine, which spares methionine requirements). Foods with high Leu/(Met+Cys) include most legumes (avg 3.2), azuki beans (4.2), kidney beans (3.8),, peas in pod (5.3), almonds (4.0), corn (3.7), green peas (2.8) with soy at (2.7). For comparison, whey’s ratio is 2.2 and egg whites are 1.5, so for a given amount of leucine kidney beans would provide only 40 % the Met + Cys load. There’s also the strong possibility in the literature that two conditionally-essential amino acids, glycine and serine, may mimic methionine restriction, and many of the same foods rate highly for Gly+Ser/Met+Cys content. I like glycine as a bedtime hibiscus tea sweetener.

      • Could you explain how cysteine “spares methionine requirements”? And where’s the evidence for serine?

        Speaking of amino acids, I’ve also read that arginine stimulates mTOR signaling and that many cancers thrive on glutamine. Comments? You’re always so insightful.

      • dorange

        What would you (and everybody else) say about the links (below) I came across some time ago?

        “Cancer cells require the amino acids glycine, glutamic acid, aspartic acid, and serine to synthesize DNA, build new blood vessels, and duplicate their entire protein contents. They also require these and certain other amino acids to synthesize other proteins that act as growth-promoting hormones or tumor growth factors. The controlled amino acid formula impairs the synthesis of a protein called elastin, which is absolutely essential to the manufacture of new blood vessels.”

        “This led to the identification of glycine – a non-essential amino acid – as a metabolite that is consumed by rapidly growing cancer cells and released by slow-growing cancer cells. Glycine is endogenously produced in both the cytosol and mitochondria; using genetic profiling, the authors determined that transformed cells have an increased reliance on either exogenous glycine or glycine produced by the mitochondrial pathway.”

        “One of the most striking results of the new data is how the pattern of glycine consumption relates to the speed of cancer-cell division. In the slowest dividing cells, small amounts of glyine are released into the culture media. But in cancer cells that are rapidly dividing, glycine is rapaciously consumed. The researchers note that very few metabolites have this unusual pattern of “crossing the zero line,” meaning that rapidly dividing cancer cells consume the metabolite while slowly dividing cells actually release it.”

        “Not all cancers show up on FDG PET scans, and that could be because some use glutamine metabolism rather than glycolysis. Or they could depend on still another nutrient, the amino acid glycine. A May 2012 article in Science found that, in a study of 1,300 samples of tumors from early-stage breast cancer patients, those whose tumors had higher levels of glycine synthesis were more likely to die from the disease.Researchers know very little about how the body regulates glycine metabolism. Yet its contribution to tumor cell proliferation only increases the evidence that changes in metabolism are a cause of cancer and not just a consequence.”

        On the other hand, it seems dietary glycine might have opposite effects?…

        Glycine as a potent anti-angiogenic nutrient for tumor growth
        ​Dietary glycine prevents the development of liver tumors caused by the peroxisome proliferator WY-14,643
        ​Dietary glycine inhibits the growth of B16 melanoma tumors in mice

  • Essty

    Isn’t this just another case of getting lost in the reductionist thinking? Which doesn’t seem very healthy. Do this one thing for longer life. There is no one magic bullet, folks.

  • Dommy


    Citrus bioflavanoids, which are found in the white parts of the rinds of oranges and lemons, strengthens the capillaries.
    Or in other words, decreases their fragility.
    Just a FYI.

  • David Pollock

    I love Dr Gregor and dutifully follow all his suggestions but I have to object to his charactorization of Calorie Restriction as a diet with constant hunger, many emotional and psychological issues, etc. The Minnesota Starvation Study is esp unfair as a basis for evaluating CR. I believe it is the study conducted during WWII using soldiers or consciencious objectors who were forced to participate in the study.
    Why not use research conducted in the last 20 years with willing participants who are committed to CR? Like me. I have practiced a vegan, CR lifestyle since 1998 and have done fine with it. I reduced my calories to 1800 (I was formerly eating about 2200). I was hungry for the first year, at times, during the day until my weight went very slowly (less than a pound per 2 weeks) down to my college weight, my body reached some kind of equilibrium and I stopped losing weight. I checked out my diet with a nutrition database to make sure that I was get adequate nutrition. Since I was eating 11 servings of veg/fruit a day with plenty of legumes and nuts, my nutrient intake was outstanding including 50 grams of fiber and 60 grams of veg protein. My bio markers are fine including 149 total cholesterol, 78 LDL and 120/70 or lower Blood Pressure. 1800 calories of vegan food, as long as you exclude the usual vegan snacks like chips, sports bars, etc is really an enormous amount of veg/fruit/legumes and hunger is not an issue. Most CR people, including those who eat animal protein, are actually eating a near vegan diet to to the enormous value placed on vegetable, fruit and legumes.

  • The Vegetarian Site

    These are all healthy foods. As Joseph Gonzales has mentioned above, Leucine (and also Methionine, BTW) is an essential amino acid, and it needs to be consumed. While you shouldn’t be swimming in whey protein shakes (whey protein is very high in Leucine), a well-rounded plant-based diet is highly unlikely to result in a detrimental level of Leucine, Methionine, or any other animo acid. You’re certainly not cutting your life short by eating soybeans, lentils, peanuts, almonds, and walnuts — unless that’s the full extent of your daily diet.

  • dd

    aventist study 2 result say that vegan live shortter lives than those who eat fish.

    • Darryl

      Not really. The mortality rates weren’t significantly distinguishable (the mean for each cohort fell within the 95% confidence interval of the other). However as AHS 2 is an ongoing study, we can expect those confidence intervals to narrow considerably.

  • Vince

    HI I looked up the Leucine amino acid content of beans & legumes and I see that they have similar levels Leucine per gram of total protein, when compared to milk , dairy products, eggs and even meat.
    So Dr. G what gives??? Should we stop eating beans and legumes too???

  • petersonl

    This question may be slightly off topic…
    I have been researching the effects of caloric restriction without malnutrition; mainly supervised therapeutic water fasting. It appears there are many benefits to this process; however, as you already mentioned it is difficult to do and not without risks. My curiosity has driven me to contemplate trying the experience for myself (supervised of course) for 2 weeks. I am a healthy woman with no major medical concerns; my only question is – could a two week water fast impact bone health? I do have osteopenia and have no idea if a short term fast could affect bone density. What are your thoughts on supervised fasting and does research support a risk for bone damage?