Always tired on a plant based diet? Here’s why.

by | May 28, 2020

Full Disclosure: The following blog is a paid partnership with Florida Department of Citrus. Sponsored posts help me continue to bring you relevant, evidence-based content. All opinions are my own and are genuine!

Moving towards more plant-based or vegan eating is a nutrition megatrend here to stay. However, plant-based and vegan are two different ways of eating. I define plant-based as trying to incorporate more plant foods into your diet. This also means reaching for more plant proteins such as soy (tofu, tempeh, edamame), pea protein, beans and legumes, nuts and seeds – while still eating meat protein on occasion. A vegan diet is based on Veganism – the belief system and practice where one does not consume, wear or use any products that involves the welfare of animals. Vegetarian is another different diet, one that does not consume animal protein, but may consume foods from animals such as dairy, eggs or fish (pescatarian) 


The number one complaint I hear from vegans is they always feel hungry  – READ THIS POPULAR POST!


Are you always hungry on a vegan diet? Check out this popular recipe HERE to help you create a more satisfying meal!


The second most common complaint I hear from all plant-based, vegetarian and vegan eaters is they often feel tired and fatigued. The reason this is happening is because when you cut out significant food groups out of your diets, you become at risk for certain nutrient deficienciesDISCLAIMER: This is not personalized health advice. Please check with your medical doctor or registered dietitian for your health concerns.


Eating a Balanced Diet

One of the biggest reasons for feeling tired is if you are consuming significantly fewer animal products, you are missing out on key nutrients, such as B12 and iron. Whenever I’m approached by women of child-bearing age, eating primarily plant-based diet with issues of fatigue and tiredness – my first response is: Get your bloodwork tested. In particular, have your doctor check these biochemical markers: Iron (ferritin is the biomarker used to measure iron), B12, and complete blood count (includes red blood cells, white blood cells, hematocrit, hemoglobin and platelets). Your doctor might request you check other blood test measures to ensure you are healthy – but that’s a conversation you need to have with them.


Looking for a delicious and satisfying vegan recipe? Check out this one HERE.




Iron deficiency is one of largest nutrient deficiencies in the world with many contributing factors. It’s prevalent in both omnivore and vegan/vegetarian diets, with the latter having greater risk for it (12). One of the most common reasons for fatigue and low energy in vegan, vegetarian and more plant-based diets is because of either low or no consumption of heme iron. This depends on the source of where you get your iron from.



Animal Sources

Animal sources, such as lean meats and seafood contain both heme iron and non-heme iron. Heme iron is the more bioavailable source of iron, easier absorbed by the body and the richest source of iron. Heme iron is only found in animal sources. 14-18% of iron consumed from a mixed diet of plants, meat and seafood protein and vitamin C is absorbed and used by the body.




Plant Sources

Non heme iron comes from plant sources (dark leafy greens, nuts, legumes, tofu) and fortified cereals (oats, enriched breads, bran).  Without getting too much into the biochemistry of why (I try to limit my blogs less than 1200 words), non-heme iron is not as bioavailable or well absorbed as heme iron. 5-12% non heme iron in vegan/vegetarian and fortified sources is usable in the human body, with certain other nutrients in these diets inhibiting the absorption of non-heme iron (34).


In dietetics, we have a measurement called Recommended Dietary Allowance (RDA), the daily intake level suggested to help people reach the nutrient requirement. Because of the lack of heme iron in plant sources of iron, for vegetarians and vegans the Recommended Dietary Allowance (RDA) is 1.8x the amount for omnivores (5).




How Can I Increase my Energy Levels by Maximizing Iron Absorption?

Consuming foods with vitamin C (ascorbic acid) is how you increase absorption of non-heme iron. Here are a few plant-based meal ideas:



Brighten Up Your Morning with Citrus for Breakfast

Instead of coffee or tea in the morning (both have shown to decrease iron absorption 67) try ½ cup (120 mL) of 100% orange juice mixed with water to go with your oatmeal power bowl in the morning. The vitamin C from the orange juice will help to increase the absorption of iron from the oats. Add other sources of plant-based iron, including nuts and seeds. Cashews, chia seed, pumpkin seeds and ground flax seeds are excellent options.



Filling Vegan Lunch

A vegan salad with marinated tofu, red peppers, and avocados on top of spinach, like this one, can help you get both your protein and iron requirements. Did you know that red peppers are actually an excellent source of vitamin C? The vitamin C in the red peppers will help with the absorption of non-heme iron in the tofu.



Balanced Bowls for Dinner

This Orange Tarragon Ginger Shrimp With Rice Noodles recipe is an excellent evening meal for people who are trying to go more plant-based by lowering their meat consumption, but are still eating seafood. Shrimp adds vitamin B12 and the orange juice adds vitamins B6, C and folate.



Workout Recovery Smoothie

One of my favourite post-workout recovery smoothies is mixing protein powder with 100% orange juice and water. Truthfully, I hate the taste of protein powder and orange juice makes it tastier and more nutritious! A plant-based protein powder, one made with pea or soy protein (both complete protein sources), mixed together with orange juice will help increase the absorption of the non-heme iron. This is especially important for young, active female vegetarians and vegans, as studies have shown the impact of both menstruation and high physical activity can lead to iron deficiency.


If you ask for my recommendation of a good plant-based protein powder, I like Vega. Not sponsored!


Summary of Plant-based Diets, Iron and Vitamin C

Of course, there are other possible nutrient deficiencies to consider when following a more plant-based diet, including vitamin B12, D, protein, calcium, omega 3s and zinc. If you are vegan/vegetarian or thinking of largely decreasing your animal protein consumption, there are supplements designed especially for you. However, as a registered dietitian, I always recommend trying to get most of your daily nutrient requirements through food and drink – if possible.
In Canada, over 80% of women and men do not meet recommended intake of vegetables and fruits per day. Research shows that a ½ cup serving (120 mL) of 100% orange juice as a complement to whole fruit consumption is a convenient way to increase absorption of the important mineral iron and increase intake of nutrients such as vitamin C, potassium, and B vitamins (8).


If you are eating more plant-based meals or are vegetarian/vegan, consider the role of important nutrients such as vitamin C and non-heme iron for adequate intake. If you still need guidance from a professional, speak to your doctor or a registered dietitian for help.


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Hi, I’m Michelle!

I’m a media nutrition expert, registered dietitian and Asian food and culture content creator based in Hamilton, ON, Canada.


Health & Nutrition