Legumes are one of the ingredient groups that has been getting a bad rap over the last few years thanks to popular diets including the Whole30, Paleo, and Banting (Low Carb, High Fat) diets. Depending on your source of nutrition advice, legumes can be viewed as either very healthy, incredibly harmful. It can be a bit confusing when some sources boast about the benefits of legumes, whilst others label them as toxic. So what should you believe? This post will take a look at some of the solid evidence that we have relating to legumes, and will hopefully help you to make your own decision regarding legumes.
What exactly are legumes?
The term ‘legume’ refers to the seeds of a family of plants that produces a pod with seeds inside . Commonly consumed legumes include lentils, chickpeas, beans, soybeans, and peanuts (peanuts are legumes, not nuts) .
What do some popular diet approaches say about eating legumes?
- Sarah Wilson’s I Quit Sugar movement. One reference to legumes that I could find in the IQS books was included in the FAQ section of I Quit Sugar for Life in answer to the question: “Should I quit carbs when I quit sugar?”. The answer to the question was: “It’s also good to limit gluten-containing foods, as well as legumes, due to the toxic load they place on our bodies” . There was no reason or explaination given for what this toxic load entails, and how it places strain on our bodies, but I am going to assume that it’s due to the fact that legumes contain anti-nutrients, which you will read more about further down this post.
- The Paleo diet discourages the consumption of legumes due to the fact that they are “…not optimal foods for human beings – just because you can’t find them at McDonald’s doesn’t make them healthy” . The argument behind this is the fact that legumes contain phytic acid, a substance that prevents the absorption of a number of minerals in the body . More on this later. The other reason put forward by advocates of the paleo diet is the fact that legumes contain FODMAPS (fermentable oligosaccharides, disaccharides, monosaccharides, and polysaccharides), which can cause digestive problems for those who have conditions such as IBS . Soy products are discouraged due to their phytoestrogen content, and peanuts are discouraged due to their possible aflatoxin and lectin content .
- Whole30. This diet excludes all legumes due to the fact that they have high levels of phytic acid (just like the Paleo supporters).
- The Banting (low carb, high fat) diet aims to reduce carbohydrate drastically. Although legumes are a great source of plant-based protein , they do contain a large amount of carbohydrates per serving. If you are trying to go low-carb, the aim is to restrict your carbohydrate intake to the point where your body relies on ketogenesis to obtain glucose (the fuel for your cells) by burning up and using body fat. When banting, “…eating carbs that are perceived to be proteins, like legumes…will undermine your attempts to burn fat” . Basically, if you want to burn fat through ketogenesis you need to reduce carbohydrate intake. Consuming legumes will increase carbohydrate intake, so they are not allowed when you are on this diet.
- Legumes are incredibly nutritious . They are unique because they are a plant food that contains a whole lot of dietary protein. This is largely thanks to the fact that they are able to fix nitrogen from the atmosphere and change it into an organic form that can be used to make amino acids, the building blocks of proteins . Farming legumes reduces the need for farmers to use large amounts of fertilizer, as they put nitrogen back into the soil for future crops . Legumes provide many other important macro- and micronutrients. One cup (177 g) of cooked red beans, for example, contains:
- 40 g carbohydrates
- 2 g protein
- 5 g dietary fibre
- 131 mcg folate (33% DV)
- 3 mg iron (29% DV)
- 6 mg manganese (28% DV)
- 5 mg copper (26% DV)
- 243 mg phosphorous (24% DV) 
- Legumes are very affordable and are widely available for most individuals around the world . Food security for an ever-increasing population is a huge challenge facing governments, farmers, and food producers worldwide . Dietitians and nutritionists aim to provide individuals from all walks of life with practical advice on how to achieve a nutritious diet at affordable prices, and this is where legumes come into play . Legumes and pulses have an important role in improving nutrition worldwide, but particularly in third world countries, thanks to their relative affordability, wide availability, and ability to be adapted to suit local taste preferences .
- Legumes contain high amounts of healthy fibres . Legumes are rich in different healthy fibres that include resistant starch and soluble fibre . Both of these fibres pass through the GIT undigested until they reach the colon, where they act as prebiotics, feeding microorganisms that live there . Although the fermentation of these fibres by bacteria is the reason behind possible bloating and gassiness when legumes are consumed, the same metabolic reactions are responsible for producing SCFAs in the colon, possibly reducing the risk of colon cancer [10,11]. Both of these fibres have been shown to also play a role in satiety after consumption  and moderating blood sugar levels after meals , which can improve weight loss and insulin response in the long run [14,15].
- Legumes have been linked to a wide variety of other health benefits . A number of meta-analyses have found an association between legume consumption and reduced blood cholesterol levels  and lower heart disease risk . Other studies have shown that the consumption of at lease 4 servings of legumes per week has the potential to reduce pro-inflammatory markers, such as CRP (C-reactive protein), as well as improve blood pressure and lipid profiles in overweight and obese individuals . There is currently a large scientific interest in determining the possible useful beneficial applications of bioactive compounds found in legumes as gut, metabolic and hormonal regulators, and as probiotic and prebiotic agents . Basically, the consumption of legumes may improve a number of different factors that contribute to the development of chronic illnesses such as heart disease.
- Legumes contain anti-nutrients that can reduce the digestion and absorption of important nutrients . These anti-nutrients include phytate, lectins, and saponins .
- Phytate, otherwise known as phytic acid, is found in all edible plant seeds . It plays a role in impairing the absorption of important minerals such as iron, zinc, and calcium from the GIT, and may increase the risk of mineral deficiencies over time if consumed in large quantities [19,20]. Deficiencies are more often seen in cases where people consume large quantities of legumes without eating sufficient animal products . The reason that phytic acid is able to prevent mineral absorption is the high number of negatively-charged phosphate groups that it contains . These groups allow phytic acid to form stable complexes with mineral ions, preventing them from being absorbed from the GIT into the body . Thankfully there are a number of methods of preparation, such as soaking, sprouting, and fermentation, that can reduce the phytic acid content and increase the nutritional value of legumes [21,22,23]. For more information about phytic acid, check out this link.
- Lectins are a group of proteins that may make up to 10% of the total protein content of some legumes . They resist digestion and can cause irritation and inflammation of cells that line the digestive tract if not cooked and prepared properly . Legume lectins are toxic in high amounts, however they can be degraded sufficiently through proper soaking and cooking of legumes before consumption . Basically the take-home message here is to never eat legumes unless they are fully soaked and cooked . For more information about lectins check out this link.
- Saponins are a large group of phytochemicals found in plants such as legumes . They are not digested in the GIT but may affect the cells lining the gut, possibly contributing to the development of leaky gut . The science behind this speculation is in its early phases, and there is currently no sound evidence to suggest that saponins in legumes do indeed cause harm in humans .
- Legumes can make you feel gassy and bloated. This is all thanks to those beneficial fibres that we talked about earlier, which pass through the GIT undigested until they reach the colon, where bacteria ferment them and produce gas in the process . There are a number of techniques that have the potential to reduce intestinal gas and bloating from legumes . These include:
- Soaking and cooking legumes properly
- Discarding the soaking liquid of tinned legumes and rinsing them properly before consumption
- Making sure to eat foods containing sugar, such as fruit, a few hours before or after a meal that includes legumes. This is because legumes are slow to digest. If a piece of fruit is consumed after a meal containing legumes it may end up fermenting whilst waiting to be digested in the GIT.
- Eating a piece of seaweed after a dish containing legumes, like many Japanese people do. This is said to make beans a bit more digestible and nutritious.
- Using digestion-friendly spices such as ginger, turmeric, and fennel. These spices are frequently used in India, a country where legumes are consumed in large amounts, to make legumes more digestible.
- Legumes are incomplete protein sources. This basically means that they lack one or more essential amino acids in the amounts that we require for growth and maintenance. Legumes specifically lack the amino acid methionine, but the good news is that consuming legumes along with other foods, either in the same meal or on the same day, helps prevent inadequate intake of methionine . Legumes can be paired with grains, nuts, seeds, or dairy products to provide the body with all of the essential amino acids that it needs . Some easy dishes that you can make using legumes that will provide all essential amino acids are:
- Beans and rice
- Hummus with pita bread
- Lentil soup with toasted bread
- Quinoa salad with black beans and feta
Legumes have been linked with a number of different health benefits when included in the diets of both healthy weight and overweight/obese individuals. They are very nutritious, boasting high fibre and protein contents. Not only this, but they are a very affordable source of nutrition for many individuals and can be used easily to prepare a large variety of different dishes. The exclusion of legumes from many popular diets today is largely due to the fact that they contain anti-nutrients such as phytate, lectins, and saponins. The good news is that these anti-nutrients can be easily neutralised through the use of techniques such as soaking, sprouting, and boiling. When prepared properly, legumes can be a healthy inclusion in a balanced, whole foods-based diet. The fact that legumes are incomplete protein sources should not put you off consuming them either, as they can be easily paired up with other ingredients to provide your body all of the essential amino acids that it needs to build and maintain body proteins.
At the end of the day, you will have to make your own decision regarding legumes. If your body feels uncomfortable when you eat them, despite proper soaking and cooking, then don’t eat them. If, however, you enjoy eating legumes, don’t feel uncomfortable and gassy when eating them, and appreciate the fact that they are an affordable source of nutrients, then enjoy them!
Enough about legumes, it’s time for you to make your own decision regarding their nutritional benefits 🙂 Whilst you’re doing that why not prepare these delicious baked coriander falafel (it turns out that the plural of falafel is falafel)? Falafel in a Middle-Eastern dish that is traditionally deep-fried and served in a pita, wrapped in a flatbread, or served along with dips as part of a mezze platter. In traditional recipes, when chickpeas are used to make falafel they are not cooked prior to frying as they tend to fall apart. I often find that this makes them difficult for me to digest, so this baked version is prepared with cooked chickpeas. We all know that deep-fried foods aren’t the greatest for our health, so baking these falafel makes them a bit healthier than the traditional kind. Although the outer crust won’t get quite as crispy as the deep-fried version, they come pretty close when fresh out the oven. Make a batch of these to store in the fridge to add to your weekday salads for some plant-based protein. Enjoy with a delicious coriander yoghurt dressing like this one, or drizzled with some olive oil.
- 2 cups cooked chickpeas
- 2 large handfuls of fresh coriander, stems and leaves
- 1/4 tsp chilli powder
- 1/2 tsp cumin
- 1 1/2 Tbsp extra virgin olive oil
- 2 cloves of garlic, peeled
- 1/2 lemon, juice
- 1 tsp salt
- 1-2 Tbsp chickpea flour, or other GF flour
- Preheat the oven to 200 degrees C.
- Place all of the ingredients (except the flour) in a food processor and pulse until well combined. Don't process it so that it becomes a paste. It should be a crumbly mixture that sticks together when pressed.
- Stir in 1 Tbsp of the chickpea flour and roll a bit of mixture into a ball. If it is a bit sticky mix in the second Tbsp of flour.
- Form the mixture into 9-18 patties (depending on the size you want), and place onto a lined baking sheet. Squish the top of the balls down just a bit to flatten the falafel slightly.
- Bake in the oven for 10 minutes before flipping over the falafel. Place back in the oven for a further 8-10 minutes, until the falafel are golden with a crispy outer crust.
- Remove from the oven and allow to cool a bit before serving.
- These can be refrigerated in an airtight container for a few days.
- They can also be frozen and eaten at a later stage.
- Enjoy these falafel with a coriander yoghurt dressing 🙂
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