Preventing Prediabetes By Eating More

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Which Works Better: Adding Beans or Portion Control?

People who eat the most legumes appear to only have a fraction of the risk for a type of prediabetes known as metabolic syndrome. Legumes are beans, split peas, chickpeas, and lentils. In one study out of Iran, people who ate three or more servings of beans a week only had about a quarter of the odds of the disease, compared to those who ate one serving or less.

Bean consumption is associated with lower body weight, a slimmer waist, less obesity and lower blood pressure in population studies, but whether the association of bean consumption with healthier body weight and risk factors of metabolic syndrome is due to physiological effects of the beans themselves or is simply an indicator of a healthy lifestyle is uncertain. Anyone smart enough to eat beans may be smart enough to eat all sorts of other healthy foods, so maybe bean consumption is just a marker for a healthy diet.

A study out of the British Journal of Nutrition put this to the test (highlighted in my video, Preventing Prediabetes by Eating More). The researchers note that reducing belly fat may be the best way to treat metabolic syndrome and reduce the risk of prediabetes turning into full-blown diabetes. “Energy restriction has been the cornerstone of most weight-loss strategies; however, evidence suggests that the majority of individuals who lose weight [by calorie-cutting] regain it during subsequent months or years.” Starving ourselves almost never works long-term. Therefore, they conclude that “it is important to identify foods that can be easily incorporated into the diet and spontaneously lead to the attainment and maintenance of a healthy body weight and improved metabolic control.”

So, for the first time ever, the researchers did a head-to-head test: beans versus caloric restriction. The bean group was asked to eat five cups of lentils, chickpeas, split peas, or navy beans a week, and the caloric restriction group was asked to reduce energy intake. In other words, the bean group was asked to eat more food and the cutting calories group was asked to eat less food. Not-so-surprisingly, the more-food group won. Not only was regular bean consumption as effective as portion control in reducing prediabetes risk factors like slimming waistlines and better blood sugar control, but the bean diet led to additional benefits beyond just calorie reduction, presumably due to some functional properties of the beans and peas.

The researchers concluded that five cups a week of beans, chickpeas, split peas and lentils in an ad libitum diet (meaning subjects weren’t told to change their diet in any other way), reduced risk factors of metabolic syndrome. These effects were equivalent, and in some instances stronger, than telling people to cut 500 calories from their daily diet. These results are encouraging news for individuals with or at risk for type 2 diabetes since they indicate that simple diet changes, such as the inclusion of beans, can have a positive impact on blood sugar control.

What is metabolic syndrome? See: Metabolic Syndrome and Plant-Based Diets.

More on plants versus calorie restriction in:

More on magic beans:

What about treating full-blown diabetes with beans? All in my video: Diabetics Should Take Their Pulses.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of DeathMore Than an Apple a DayFrom Table to Able, and Food as Medicine.


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

74 responses to “Which Works Better: Adding Beans or Portion Control?

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  1. My husband and I feel best when we eat beans and miss them if we skip a day. I serve bean dishes every night for dinner like split pea soup, a variety of lentil soups, minestrone, chili etc.

    1. Its a bit hard for me, being single…making beans i like them but have way too many left over after eating them for 3 days straight…if i dont put onions or garlic in them i have been feeding them to my dogs which they inhale them!

      1. Maggie: A tip for you: Beans freeze *very* well. So, when I cook up a big pot, I save some out for me to eat for a few days. But I also put 1.5-1.75 cups worth into jars and freeze them. Then when a recipe calls for “a can of beans”, all I have to do is pull out one of the jars. Just an idea.

        1. Didnt know you could freeze cooked beans….ok maybe, bag them and then freeze!…good idea but i still use them in my dog food mix up i give em…got some big dogs and hungry cats! thanks

          1. june: Yes, I freeze them without any liquid. (I don’t try to make them dry to the touch, but I don’t have them swimming in liquid either. And when they come out, they come out both tasting perfect AND still a good texture. To me both taste and texture is very important. If you try it and it works for you, let us know.

            1. It works great to cook up a large batch of legumes of any type, put into containers and freeze. You can make them with or without liquid. Personally I don’t like runny legumes. As soon as one container is used thaw out another. I’ve done this for many years.

  2. I like beans but my issue with beans has always been allot of gas no matter how I use them. I have tried going very slow and increasing them but it is always the same result. Is there a remedy for eliminating the gas??? I don’t want to have to take something like Beano or GasX all the time just so I can eat beans. But I would sure like to know how to prepare them so I don’t have issues. I currently take HCL Betaine and enzymes and probiotics. Any thoughts??

    1. I’m told that you can put kombu seaweed in the pot while cooking and it will cut down on gas. We use this in our pressure cooker when cooking beans.

      1. Yes, I have heard a small strip of kombu works, too! Nice work on the pressure cooker. I think we could start a Pressure Cooker Fan Page based on the amount of folks here I see that use one ;-)

        1. Joseph, how does Dr. Gr., as well as yourself, feel about the use of supplemental digestive enzymes? Is there science saying they are harmful and or helpful? How about for those with macro biomes that struggle on a plant based diet? And, if we don’t have the bacteria in our guts to handle certain foods (some people can’t digest meat well), could it be that digestive enzymes provide a fix? Thank you for any follow up.

      2. Dr. Greger tells us not to use konbu, too much iodine, you don’t want to be adding kombu to your beans 5 times a week. Also I hope people don’t follow this advice because, I am taking what I consider the correct mdosage of iodine, and beans are one thing that I can eat while out in the world grazing among the carnivores,. Now do I have to ask everyone if there is kombu in the beans?

        I never noticed any more gas with beans than anything else, and we eat quite a lot of beans, but I do make a point of buying fresh beans. And I know if my beans are fresh because I 1) buy beans at a store where a lot of vegetarians shop and they have a high turnover in beans. 2) have experience in cooking favorite beans and I know how tender they are supposed to get how fast. If they aren’t getting tender in reasonable time, I throw them out, I don’t add the other more expensive ingredients. But that rarely happens because 1) I shop at the same place that sell a lot of bulk beans. 2) I notice when the new crop of bulk beans come in. 3) I notify the store when I get a batch of old stale beans. They’re nice about it and I’m nice about it, but that gives the store an incentive to keep their bulk foods fresh. They need to know that their good loyal custumers notice. With experience you can do this too and we will all eat better

        I have one food combining rule: Don’t put bananas in the same stomach with beans! Other fruits don’t seem to present much of a proble, though I wouldn’t serve a fruit salad with beans. Citrus and beans go together well, in fact one of my favorite bean dishes is Columbian Black Bean Soup garnished with oranges (I put lots), lime juice, cilantro and onion. It’s from the Voluptuous Vegan, and I make a fat-free version, skipping the olive oil and sautéing.

      3. I boil the beans for two or three minutes, then let them soak overnight and then rinse before cooking. You will lose some B vitamin, but that will cut down on the gas.

      4. I put baking soda and sometimes ginger in beans but doesnt Dr. Gregor say to use Beano?…I think once your gut is accostume to eating beans on a regular basis the gas goes away….

    2. The remedy for getting rid of gas is to eat beans or lentils 5x/day for 2 weeks – about 2 Tbsp at a time. Eating this many builds up the correct intestinal bacteria in enough quantity to break down the bile bound to the excess hormones and metabolic wastes that the beans are drawing out (which causes the gas in the first place). The gas is from the fermenting ‘crap’ the beans are cleaning out – what the liver is trying to remove from the body. Eat more beans, clean out more rubbish and you’ll find gas is no more problem any more.

    3. Alan, I totally sympathize with you. When I made the switch to WFPB diet let me tell you I could have inflated a circus balloon all on my own. And let me just add that the odor issue went right along with it. It’s a good thing I live alone as it would have been really difficult for someone to put up with this production – and I’m not saying this to be funny. It was seriously serious. But I encourage you to stay the course. It took my body about 2 years to really make the complete adjustment but now I can eat anything that typically causes gas – which many vegetables do as well – and respond with a normal production of flatulence. And the severe odor is a thing of the past as well. So keep at it. Best of luck.

      1. GEBrand, I did this diet about 2 years ago using The Eat To Live Plan by Dr Fhurman and lost 20 lbs in 6 weeks and felt great. But your correct, I could have filled a Hot Air Ballon. I ate daily 1 lb cooked and 1 lb raw veggies a day, lots of soup and salads but beans just killed me. Same for onions, cauliflower and broccoli. I ate some tubers but very few. No fat. This is why I lost the weight. Not eating fat makes the body use the body fat for fuel, so you burn you own body fat and weight loss was a cinch! I started talking HCL Betaine along with digestive enzymes recently and foods that used to give me gas I can now tolerate better. I suspect I was not digesting properly. Thanks for the info.

        1. I’m not sure about your burning fat theory. I think it’s more a matter of caloric density and overall caloric intake. You were likely consuming less calories on WFPB/ETL without reducing volume of consumption due to the lesser caloric density of carb-heavy plant foods compared to fat-heavy animal and processed foods.

        2. I’m not sure about your burning fat theory. I think it’s more a matter of caloric density and overall caloric intake. You were likely consuming less calories on WFPB/ETL without reducing volume of consumption due to the lesser caloric density of carb-heavy plant foods compared to fat-heavy animal and processed foods.

          1. Well for one, it is not theory if it works, which it did for me. Not a starchy carb diet. Mostly berries, non starch veggies and the like. Cooked veggies and raw, 1/2 of each and 1 lb each a day. No fat eaten at all. The thing is if one goes back to old eating habits, the weight will come back. So if your old diet is highly fatty and starchy carbs, you would put all the list weight back on. But it is ideal to get to where your normal weight should be.

            1. I don’t think that not eating dietary fat forces your body to burn body fat, as you suggest. All that I am saying is that it is a matter of calories in — calories out, even with WFPB, but WFPB is very conducive to losing weight due to the lesser caloric density of foods that are naturally very low in fat.

              1. When I stopped eating fat, I also began to lose weight. It’s working for me, and I eat all I want–grains, legumes, fruits, vegetables. When I counted calories, that didn’t work. Not counting calories but eating right is working for me–and I even allow myself a few nuts on occasion….

    4. Using Kombu & then discarding it works but I also soak a batch of dried beans not only overnight but at least two nights, throwing away the soaking water as well as the cooking water then fill the pot up again to cook the beans until they are soft.
      This way you are ready for the week, you can divide them into single portion sizes then freeze or refrigerate what you don’t use . That is if you prefer not using canned beans.
      Another method I heard was putting a teaspoon of Baking soda in with the soaking beans(discard the soaking water later on), I wonder what Joseph thinks of this?

    5. Alan, have you tried soaking them over night? I always soak my beans overnight, I actually prefer to pick through them in the early morning and start them to soaking. I allow them to soak all day in to the night, then I pour the water off of them, rinse them a couple times, and start the soak again, putting a pinch of baking soda in the water, and let them continue to soak until the next morning. I pour the water off, rinse them again, then cook them. This usually takes care of the gas. And it works even better if They are cooked in a crock pot. This is how my mom and grandmothers did it, and I just followed suit. And if I don’t soak my beans overnight, I at least try to soak them for 8 hours.

    6. Dietitians Vesanto Melina and Brenda Davis, authors of the excellent resource guide “Becoming Vegan,” suggest using common spices–including garlic, ginger, cloves, cinnamon, cumin, turmeric and black pepper. Check out their tips for fending off flatulence at and start off this new year with some Hoppin John prepared with spices. Hopefully you’ll hear more ringing and less tooting.

  3. We also cook a large variety of beans and legumes throughout the week. If you soak dried beans overnight, it takes just 10 minutes to cook in the pressure cooker. We frequently cook black beans, kidney beans, cannellini beans, pinto beans, and black eyed peas that way. I make a lot of cold salads with them. Just add chopped celery, carrots, onion, and dressing.

  4. The abstract for this study has an interesting finding they do not delve into: “Insulin AUC decreased in both females and males on the energy-restricted diet by 24·2 and 4·8 %, respectively, but on the pulse diet it decreased by 13·9 % in females and increased by 27·3 % in males (P < 0·05)".
    Although insulin resistance may be improving, it is worth noting that males actually secrete more insulin, which isn't pathological necessarily. I am curious to if it is known why we would see these splits between genders, since combining groups we see female insulin levels drop while male insulin levels rise.

    1. Great question. You might need to delve into the paper and read if the researchers give any explanation. I think the main take away is the conclusion though: “frequent consumption of pulses in an ad libitum diet reduced risk factors of the MetSyn and these effects were equivalent, and in some instances stronger, than counseling for dietary energy reduction.”

      Similarly, a nutrient-dense approach for weight loss may be much better than the typical advice to “reduce calories.” And I’ve seen the same thing in this study: A multicenter randomized controlled trial of a plant-based nutrition program to reduce body weight and cardiovascular risk in the corporate setting: the GEICO study, which Dr. Greger highlights in Plant-Based Workplace Intervention. Other studies that use this approach can be found in Dr. Barnard’s research where study participants received either a low-fat strict plant-based diet or a typical diet for diabetes and found significant changes in weight loss and insulin levels. Note that many of these participants were men and many consumed a lot of beans. Dr. Greger presents the study in this video. So it appears this type of approach “not” counting calories works for weight loss and diabetes management.

      Lastly, a few more videos on calorie restriction vs plant-based diet and benefit of calorie restriction without actually restricting.

      1. In this article they do NOT specify if the cup of beans/lentils is cooked or if it is the measured amount is UNCOOKED. It is important to know. I’m assuming they meant cooked❓⁉️

    1. You know you’re supposed to soak them then COOK them, right? :)

      I don’t ever bother with the soaking part. I just throw them in a covered casserole dish and throw them in the oven, checking on the water level from time to time. It’s even easier if you use a Dutch oven because there’s less water evaporation. Bake at 325 for 1.25 – 1.5 hours and they should be good.

      As Seedy pointed out, the older the beans are the harder they will be to cook. If they’re still tough, just top up with hot water and keep on baking.

      1. I actually find dry beans easier. You can measure more precisely from dry, and have no need to crank open, spoon out, scrape, then prepare a soiled can for recycling. Moreover the typical size of a can is not enough for the more efficient forms of meal preparation, and the inconvenience of cans rises relative to dry the more and more cans you have to use. The main advantage of cans is less need to plan.

  5. I don’t eat a lot of beans because I don’t like them. The only kind of bean I like is chickpeas. But I eat a lot of lentils. I don’t know which is nutritionally superior. Any thoughts? (One advantage of lentils over beans is that lentils are much easier to cook. Soaking is unnecessary and they cook faster with less water.)

    1. george: I believe that people often say beans as a quick and easily identifiable term, but what they really mean is ‘legumes’, which definitely includes lentils. And actually, if you look closely at the article above, you will see that lentils were included in the ‘bean’ group: “The bean group was asked to eat five cups of lentils, chickpeas, split peas, or navy beans a week, and the caloric restriction group was asked to reduce energy intake.” So, by eating lots of lentils, you are good.

      Even more, you are using one of my favorite techniques for “picky” eaters (myself included). Say, someone *generally* does not like vegetables. But usually, people will have at least one, if not two or three, vegetables that they like. So, I suggest using the vegetables that they like as ‘gateway’ vegetables. Eat a lot of them and then keep testing small amounts of other vegetables, especially when mixed in with the ones you like. You can slowly expand your list of acceptable vegetables. This technique has worked well for me. You are starting with lentils and chickpeas. You could expand your list of ‘likes’ over time.

      I’m not saying you have to eat other forms of legumes to be healthy. My understanding is that lentils are plenty healthy. But *if* you would like to work toward some variety and/or are worried about lentil burn-out, you could start to experiment with other beans. For example, I’ve become a big fan of the puy/(French green) and black beluga lentils. They are technically lentils (as far as I know), but when cooked to al-dente, they have a mouth feel of tiny beans, which I personally like better than the mushy lentils. While beluga lentils may be my gateway food to say red lentils, they may be your gateway food to say black turtle beans. If that is something you are interested in moving toward.

      Those are just my thoughts. What do you think?

    2. This video compares different beans to some extent. Any bean you like is a good thing and will keep you eating more of them. If you are eating lentils and chick pea that’s great you’ll obtain so much protein, minerals, fiber, and antioxidants.

  6. The nice thing about cooking extra beans is that they can be added to the next meals and go well with many dishes. I have found that regular bean consumption has helped with the gas issue, or you could just watch the movie Blazing Saddles and have a good laugh.

  7. During the wintertime, I may very well be eating too many legumes. I eat about 8 ounces of dry split peas worth of crock pot split pea soup almost every day, and I can’t stop because it’s so tasty and cheap. Then on top of that, I frequently consume red lentil hummus, tempeh, and a protein powder containing pea protein after workouts. Is there an upper limit on the amount of legumes a person should eat?

    1. Not really. Of course, as always stated here, quality matters more than quantity. I don’t think that is too much and you’d surely know if you overdo it. I might say that pea protein powder may not be needed since you do eat so many, but that is up for you to decide.

    1. The difference lies in how they are processed. Both are the seeds of Pisum Sativum.
      Green peas are younger and served as a vegetable but technically are a legume as are the split peas.
      Split peas are a product of garden or English peas. The peas or seeds grow inside inedible pods. Some garden pea plants produce wrinkled seeds. These seeds are often harvested about 18 to 21 days after flowering, when the peas are large, sweet and tender. Usually garden pea plants with smooth seeds are allowed to grow until the plant is fully mature and the pods turn tan. The peas are removed from the pods, dried and used like beans. They are also called shell peas.

  8. Apparently if you grow beans you must be careful , as it contains a toxic compound called phytohamagglutinin (a lectin)
    and therefore they need to be pre-cooked (and water discarded) at boiling point for minimum of 10 -30 mins to deactivate the toxin. We do this anyway with dried beans , but I thought this information might be helpful for those home gardeners
    who are thinking of growing your own beans.

    1. Many folks argue lectins are harmful, but you got the right idea that cooking basically takes care of it. From the good doctor’s transcripts:

      “Consuming too many lectins can cause significant gastrointestinal distress. However, because legumes and grains are almost always consumed in a cooked form—and lectins are destroyed during cooking—eating beans and grains doesn’t result in lectin overload. Sprouting also reduces lectin levels in plants, although not as effectively as cooking. Generally, pea sprouts, lentil sprouts, and mung bean sprouts are safe to consume, as are sprouted grains, which are naturally low in lectins”

      1. I did not know that sprouting can deactivate the toxic compound as well, thank you !
        When we grow our own , it is easy to forget the rules & steps for preparation sometimes and end up with problems.

        Another tip I found was to pour a cup of cold water the moment the boiling temperature(pre-cooking) is reached (for the Legume) to minimize the difference of temperature between the core and the outer-shell/skin which could result in coagulating the surface of the legume/beans. When this occurs, legumes apparently become very hard & brittle no matter how long it is cooked. (Ref:

    2. “Because cooking temperatures under 176 °F do not destroy lectin, use of slow cooking and/or a crockpot is not advised for cooking beans.” Source: Boil for at least ten minutes or steam, according to that article.

      One legume, however, has lectins that survive even high heat, according to a scientist in England. The outlier? Peanuts See

      1. Steaming sounds quite handy, since I sometimes only use a small portion from the garden.
        Thank you for that link as well.
        I wonder too, if some people are having bowel discomfort after eating beans that are cooked but not quite long enough at the temperature it’s supposed to be, or if the precooking water was not thrown out when a crock pot or a pressure cooker is used? This is only a hypothesis though.

  9. Thank you for sharing the specifics of how much beans were consumed. This is what I need to work on – getting those 5 cups in per week. Thanks again!

    1. They have this fantasy about what paleolithic humans ate that says that grains and legumes were only introduced into the human diet 10,000 years ago with the advent of farming. As such their hypothesis is that since we didn’t evolve eating these foods and they don’t think that 10,000 years is enough time for substantial evolution to have happened to adapt us to eating them, we shouldn’t eat them. Of course this is pure non-sense. Even if we didn’t evolve eating them, that doesn’t mean that they are automatically bad for us. They could be novel *and* beneficial. Early farmers didn’t just suddenly start planting fields full of wheat, rice, oats, and beans of many types that none of their ancestors ever ate. Before large scale farming communities there is evidence of casual farming where nomadic peoples would plant back a percentage of their grain in small scattered plots and return to harvest when the time was right. There is evidence of people eating oatmeal over 30,000 years ago. There is even evidence of humans gathering and grinding grains and legumes up to 100,000 years ago. But even if it was only significant was only a significant source of food in the 10,000 years ago, there is no reason to believe that we couldn’t have adapted to it and some clear evidence that we have. The paleo advocates also argue against grains because they say that it made the early farmers weaker and sicker than their HUNTER-gather ancestors (based on body size). However, this actually an argument against their hypothesis since health impacts would be a strong evolutionary selector for people in the population that were healthier on this “new” diet. Maybe grains and legumes did negatively effect even a high percentage of early farmers’ health. If there was even a small percentage that had genetic variants that allowed them to thrive on the new food then in a very short period of time those variants would come to dominate the population. There are current examples of dramatic evolutionary shifts in diet on the order of decades or centuries given a strong enough evolutionary pressure. 10,000 years is more than enough time to shift the population to be able to eat grains and be healthy.

      And all of this is completely besides the point. We have the scientific method and the ability to experiment of the humans that matter, us. And the science clearly shows that grains and legumes promote the long term health of current day humans. Who cares about some elaborate Just-So story when it comes to a conclusion that doesn’t match up with observed facts.

      1. Like you I am rather skeptical of that theory. if you look at the aborigines of Australia and the extensive knowledge the elders have about where to find all the nutritious plants, how to cook them without poisoning oneself is truly amazing. Eating plant based requires a lot of knowledge than barbecuing a piece of meat. I think we tend to think of ancient humans and their intelligence in a patronizing way, I think they were very knowledgeable even-though they did not call it ” science “.

  10. Some commenters have suggested gradually eating more beans to cut down on gas. I believe if you just suffer the gas and keep eating them, your body adapts and the gas decreases. I seem to recall reading that putting baking soda in beans destroys important nutrients – not sure if true or not. My daughter gets migraines from beans – does anyone know why that might be or what could be done to prevent it?

  11. We add beans to boiling water, and no salt, and bring them back to a boil for two minutes. Then let them stand covered for an hour. (You may wish to pour out that water at the end of the hour. Though this is not essential when you pressure cook them afterwards.) Then we add sufficient salt to taste and pressure cook the beans for twenty minutes and have no gas troubles. This works with pinto beans, black beans, chick peas or any beans of roughly that size.

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