The Dangers of Plant-Based Diets: What You Need to Know Before Going Completely Green

Plant-based is a huge buzzword right now. The trouble with buzzwords is they get used so often and so loosely that they lose some of their satient clarity—when it comes to educating ourselves about our health, clarity is key. 

What does being 'plant-based' even mean? 

Popular chains are coming out with plant-based burgers and breakfast sandwiches, leading many people to (understandably) believe they're choosing a healthier option. But when we break down the ingredients in these franken-veggie concoctions, we find they're chock full of sodium, fillers and some not so great additives. All in all, they're not much better (and arguably worse) for you, than their meat alternatives. 

But that doesn't mean you shouldn't try a plant-based diet. It just means you need to understand the TWO fundamentals of eating a healthy plant-based diet before you get started.

1) Being plant-based does not necessarily mean you have to be a vegan or vegetarian.

It may simply mean that most of your diet comes from plants. You can predominantly eat a plant-based diet, and still eat some meat. Take a look at our Nutrition Guide & Meal Plan and Fast & Furiously Fit ebook: half of the recipes are vegan or vegetarian, while the remainder are heavily plant-based. These nutrition plans are plant-based, but not plant-exclusive, even though plants are the foundation for almost all of the recipes. You can grab our Fast & Furiously ebook now for 30% off with promo code FASTED30

2) Being plant-based does not automatically mean you are eating a healthy, balanced diet.

Processed foods, in any form, are seldom as good for you as clean whole foods. The same goes for plant-based mystery meatless patties.

Even if you eat mostly whole plant-based foods, you may not be getting all the nutrients you need to support your healthiest body. Some nutrients are simply more readily available in the right quantities from meats and animal by-products. Failure to ingest adequate amounts of these vitamins and minerals can lead to malnutrition, and with it, all the physical and mentally devastating effects of a deprived body.

Here are the main micronutrients missing from purely plant-based diets:

  1. Omega-3s

Omega-3s are essential for heart, skin, eye and brain health, that need to be supplemented as our bodies cannot produce them on their own. Omega-3s are composed of alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). ALA is abundant in plant-based sources, like soybeans, walnuts and flaxseeds. While your body can convert some ALA into DHA and EPA, this conversion only yields a small amount. Adults require a minimum of 250-500 mg of EPA and DHA combined, to support proper health. EPA and DHA are found in fatty fish, like sardines and salmon. Vegan EPA and DHA can be found in seaweed and algae, but you'd have to consume a lot to provide your body with an adequate amount. Thankfully, there are seaweed and algae supplements for people who don't care to start eating sea vegetation.

  1. Iron 

Iron is essential for maintaining good blood health. Iron helps red blood cells transport oxygen throughout our bodies and plays a critical role in cellular energy function. This is why fatigue is one of the first signs of iron deficiency. Chronic iron deficiency can lead to immune weakness, hair loss, breathing problems and even heart failure. So obviously, getting enough of this essential mineral is important. However, it may be problematic if you only chow down on plant-based foods. 

Here's why:

There are two types of iron: heme and non-heme. Heme is found in animal products and in this form, is more readily absorbed by the body. Non-heme is found in plant-based foods, like beans, dark leafy greens (e.g. kale and spinach), potatoes, dried fruits, nuts and seeds or palm hearts. Your body can only absorb between 2% and 10% of iron from non-heme food sources.

The recommended daily intake (RDA) for men and post-menopaual women is 8 mg. The RDA for pre-menopausal women is 18 mg per day and 27 mg per day for pregnant women. 

So, a diet rich in iron is especially important for vegans and vegetarians. You can boost your intake of non-heme iron by consuming iron-rich foods with vitamin C. But, too much iron can be just as dangerous as not enough. A surplus can block the absorption of other minerals from your gut, damage cells, cause convulsions, organ failure, coma or even death. Before you consider iron supplementation, talk to your doctor and request to have your iron levels checked to determine if supplements are necessary. 

  1. Vitamin B12

Vitamin B12 is found abundantly in meat. Not so much in plants. B12 is necessary for protein metabolism. It also aids the formation of red blood cells, and is essential for supporting a healthy nervous system. Vitamin B12 deficiency can cause anemia, damage to the nervous system, as well as bone disease, heart disease and infertility. 

The daily recommended intake is 2.4 mcg per day for adults, 2.6 mcg per day during pregnancy and 2.8 mcg per day while breastfeeding. 

Vegans can consume B12 by eating fortified foods like fortified nutritional yeast, soy products, breakfast cereals and plant-milks. Yes, some plant foods contain a form of B12, but there is debate as to whether or not this form of the vitamin is active (biologically available) in humans. Again, consult your doctor as to whether you require supplementation.

  1. Iodine

Iodine is essential to supporting and regulating thyroid function, and, concomitantly, metabolic health. Unless you are eating plenty of seaweed, your iodine levels could be in short supply.  This can cause symptoms such as low energy levels, tingling in the hands and feet, forgetfulness, depression, dry skin and weight gain. 

Vegans, in particular, are at considerable risk of becoming deficient. Studies show that vegans have up to 50% lower blood iodine levels than vegetarians. 

Iodine is found in seafood, eggs, dairy, and conveniently, iodized salt, making this an easily remedied deficiency. 

The RDA for adults is 150 mcg of iodine per day. Pregnant women should aim for 220 mcg per day, and breastfeeding women are advised to increase their daily intake to 290 mcg.

  1. Zinc

Zinc is another mineral critical for optimal metabolic function. It also supports cellular health and a robust immune system. Zinc deficiency can lead to hair loss, diarrhea, as well as slow healing and an increased risk of heart disease and cancer. It’s also been linked to depression.

The RDA for zinc is  8–9 mg per day for adults. This recommendation increases to 11–12 mg for pregnant women and 12–13 mg for breastfeeding women. While plants are not devoid of zinc (seeds, nuts, potatoes, green beans, kale or quinoa), meat or shellfish contain much higher levels of zinc. 

What's more, plant-based sources of zinc can have their absorption rate stymied by their phytate content. Phytate is a naturally occuring acid (despite its many health benefits, like being a powerful antioxidant) that can impair mineral absorption. However, sprouting, soaking and lactic acid fermentation have been shown to reduce the amount of phytic acid in some plant-based sources of zinc.

  1. Calcium

You don’t need to drink milk or eat dairy to get enough calcium. But, you do need to be mindful to consume the right kinds of calcium-rich plants to support optimal bone health.

Oxalates are compounds found in certain calcium-rich plants that can inhibit calcium absorption. So, while almonds, spinach, beets, nuts, oranges, Swiss chard and rhubarb are good sources of calcium, they're also higher in oxalates. The best greens for calcium are kale, collards and mustard greens. You can even eat calcium-fortified plant-milks or fruit juices.

The RDA for calcium for men 19-50 years old is 1,000 mg to 2,500 mg. For men 51-70 years old, 1000 mg to 2,000 mg. For men 71+, it's 1,200 mg to 2,000 mg. For women 19-50 years old, the RDA is 1,000 mg to 2,500 mg. For when 51+, it's 1,200 mg to 2,000 mg. 

  1. Vitamin D 

Vitamin D is more bioavailable (able to have an active effect in the body) in animal products. This micronutritient is found in fish, dairy and eggs. Vitamin D is best known for improving calcium and phosphorus absorption. But it can also help with depression, weight loss, fighting off disease, supporting good heart health and maintaining normal immune function. You can get most of your vitamin D intake from the sun, but if you spend most of your time indoors, it’s good to get it from foods, too. 

If you’re 100% plant-based, mushrooms (especially ones that have just been in the sun) or fortified foods like tofu and plant-milks are your best bet. Of course, supplements are solid options too. 

The RDA for vitamin D for adults is 600 IU for  adults up to 70 years old, and 800 IU for adults over 70. The safe upper limit is 4,000 IU per day.

Finally, the BIG question: am I getting enough PROTEIN on a completely plant-based diet?

Protein and Plant-Based Diets

We’ve written an entire article on this topic, and we suggest you read it here. Here’s the gist of it though: Yes, you can get enough protein on a plant-based diet from food alone, but it’s a hell of a lot harder. Ask any successful vegan bodybuilder, and they'll tell you protein supplements are their BBFs. On average, you need at least 1.2 g of protein/kg of bodyweight if you’re sedentary, all the way up to at least 1.8 g/kg if you’ve active.

For example, an active female weighing 61kg (135lbs) who’s trying to lose fat is going to have to eat a whopping 110 grams of protein a day. You'd have to eat a ton of beans and rice to do that. Since a lot of plant-based forms of protein are also higher in carbs, eating that many carbohydrates per day would counteract your fat loss goals. 

Here’s an awesome protein requirement calculator by an extremely reputable site. Use it to get your number. If you’re looking at your recommended intake, and you believe you can't achieve that number through diet alone, consider supplements. Simply Protein and Iron Vegan are both solid, clean and tasty protein brands. 

We know: all this is a lot to consider. But we don’t believe in giving pat, reductive, fast-fix answers when it comes to giving advice. Especially when it concerns something as important and intricate as your health. You don’t have to wake up one morning and swear off meat. Take your time and consider what's best for you, and if you want to make the switch to a plant-based diet. Undeniably, it has many benefits for your body and the planet, but it has to be done mindfully and armed with the right information. 

Want to jumpstart your plant-based diet? Grab our Nutrition Guide or the Fast & Furiously Fit ebook now. Remember, you can use promo code FASTED30 for 30% off the Fast & Furious guide. 


Hi Barbara! I’m Hollay, BodyRock’s Content Manager & author of this particular article. Thanks SO much for your feedback. Well thought out and realistic is the name of the game! 😊

Hollay September 04, 2019

Finally, a well thought out and realistic piece on the craze around plant based diets.

Barbara J Walker-Walsh September 03, 2019

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