Plant-based diets have become increasingly popular in recent years, with many people choosing to adopt them for health, environmental, or ethical reasons. In this article, I will explore the origins of plant-based diets, their current state, health benefits, potential side effects, and their suitability for athletes. I will also discuss how plant-based diets can help with weight loss and their impact on the environment.

Origins of Plant-Based Diets

Plant-based diets have been around for thousands of years. Much of their history arose in 1500 – 500 BCE on the Indian subcontinent. Also, the ancient Greeks, including athletes, were known to consume plant-based diets, with records dating as far back as 6th century BCE. Aside from that, the early hominids from roughly 2 million years ago were primarily vegan, with opportunistic omnivorous behavior. Today, while plant-based diets are becoming more popular, relatively modest proportion of 5-10% of people worldwide are eating them. There is a spectrum of plant-based diets, ranging from pescatarian to lacto(-ovo-)vegetarian to vegan. No diet is perfect for everyone, and it’s critical that you consider what foods are available to you, what foods are your staples, and what you can do without, when determining which diet to follow (i.e. the structure of your diet).

Health Benefits of Plant-Based Diets

One of the main motivations to opt for a plant-based diet is that they have been linked to a variety of health benefits. For example, plant-based were reported to reduce the risk of ischemic disease by 25% and even lower the overall risk of cancer by approximately 10% for some types (Dinu, Abbate, Gensini, Casini, & Sofi, 2017). There is also strong evidence that they reduce the risk of diabetes by 28% (Lee & Park, 2017). Let’s note in passing that 10% of the worldwide population has diabetes(, which is a tremendous socioeconomic cost, so anything that can help alleviate that should be seriously considered. While the above benefits are very concrete, the studies could not control for the confounding fact that people who decide to adopt-plant based diet tend to lead healthier lifestyles (fewer smokers, less overweight, more frequent exercise, less alcohol, …). It remains disputable whether there is any inherent benefit to eating plant-based per-se, and if there is one, it will most probably be small. It’s more likely that the true benefits of plant-based diet come from increasing our awareness about what we eat, supporting adoption of healthy lifestyle patterns and facilitating adherence. This includes removing processed meat, which is known to increase the risk of cardiovascular disease, stroke, colon, and rectal cancers (Micha, Wallace, & Mozaffarian, 2010; Kaluza, Akesson, & Wolk, 2014). Furthermore, there is strong evidence that high temperature cooking (such as pan frying, charring, barbecuing) leads to formation of carcinogenic compounds and that amounts of these are particularly elevated in red meats (Zheng & Lee, 2009; Pan et al., 2012). Plant-based diets avoid consuming meats prepared in this way as they avoid meat in the first place (duh :)). While the health benefits of plant-based diets may be indirect, this in my opinion does not subtract from their attractiveness for reaching certain health goals. However, even a plant diet can be an unhealthy one. It’s critical to eat whole and healthy foods, irrespective of diet’s structure. That means avoiding processed and high-added sugar foods and consuming equilibrated profile of macro and micronutrients. Such a diet would also lead to higher fiber intake which is implicated in the reduction of risk for colon and rectal cancers. There is nothing wrong with fat either, it’s unprocessed sources such as nuts and seeds tend to be high in fat-soluble vitamins (A, D, E, K) and the healthy mono/poly-unsaturated fatty acids. Consuming an unhealthy plant-based diet is associated with poor health outcomes, even worse than control (so people who keep eating whatever they ate, including processed meat, and not adjusting their lifestyle) (Satija et al., 2016). Finally, the above highlights the importance of lifestyle when it comes to health outcomes. To optimize health outcomes, it’s vital to look beyond diet and consider your sleep, exercise, alcohol intake, smoking, and mental fitness.

Plant-Based Diets for Weight Loss

Plant-based diets are generally effective for weight loss. However, research shows that other diets can be equally effective, irrespective of their structure (i.e. if they are plant-based or not) (Gardner et al., 2007). In the end, it turns out, the rule of weight loss is quite simple (that is, for most healthy individuals): On day one, consume fewer calories than you burn, on all consequent days, repeat. The advantage of plant-based diets is that they facilitate this, as plant-based, unprocessed (!), foods tend to be less calorie dense. Vegan diets are in this sense even more effective than other plant-based diets. Finally, being a (lacto/ovo-) vegetarian or vegan, is for many a part of their identity, and stops being a decision they would have to face every time when deciding what to eat, which greatly helps with adherence (an idea popularize by James Clear in his book Atomic Habits).

Potential Side Effects of Plant-Based Diets

Many will be held back from adopting or trying plant-based diets due to concerns about their side effects. Let’s look at how much these are substantiated. It’s true of any diet, that by omission of certain foods, it may be harder to reach macro and micronutrient goals. This is not an exception for any plant-based diet. On large sample level, these tend to lead to nutritional deficiencies. For example, up to 86.5% of vegetarians do not have adequate levels of vitamin B12 (largest of the B-complex vitamins containing cobalt in its structure essential in multitude of processes in our bodies) in their blood (Pawlak, Lester, & Babatunde, 2014), and iron deficiency can be seen in up to 79% of females and up to 29% of males who adopt plant-based diets (Pawlak, Berger, & Hines, 2016). This is not because plant-based diets contain less iron, but because it comes in forms and combinations that make it less bioavailable. Plant-based diets are also deficient in choline (an essential nutrient and a source of methyl groups needed for many steps in our metabolism and required for synthesis of neurotransmitter acetylcholine), but there is insufficient research to show if this has any negative health implications. Next, plant-based diets are generally deficient in omega-3 fatty acids. While some plants are good sources of the short-chain form, the long-form is found mainly in fish. Our body can to some degree convert the short-chain into long-chain fatty acids but does so only with 2-5% efficiency. Plant-based diets are also generally higher in carbohydrates, lower in fat, and lower in protein. A person following a plant-based diet eats on average 20-30% less protein than an omnivore. This is generally not a problem but may become a concern for someone with a very active lifestyle (see below). There is evidence to suggest that individuals who follow a plant-based diet, especially those who follow a vegan-diet, are exposed to more phytoestrogens (Tordjman et al. 2016), which are plant derived hormone-like molecules that activate the estrogen receptor. While this has been associated with lower testosterone levels in males, more recent research shows lack of correlation and additionally suggests that estrogens have positive effects in treatment and prevention in rage of indications including skin aging, osteoporosis, cancer, cardiovascular, neurodegenerative, immune, and metabolic diseases. Additionally, estrogens have been reported to help alleviate menopausal symptoms in women (Sirotkin & Harrath, 2014). Overall, there seems to be little to no negative effect associated with elevated phytoestrogen exposure.

Plant-Based Diets for Athletes

Plant-based diets are compatible with active lifestyle and can be even preferable for endurance athletes such as runners and cyclists. The elevated carbohydrate consumption provided by plant-based diets translates to an increase in the amount of stored muscle glycogen. Glycogen fuels muscle contractions during intense or prolonged exercise and its increased storage helps with endurance. The general lower calorie intake of plant-based diets can also help maintain weight in certain categories and overall optimize lean muscle mass. However, a chronic insufficient calorie intake is one of major risk factors for injury and illness among athletes. Besides general calories insufficiency, plant-based diets tend to lead to micronutrient deficiencies, as highlighted earlier, and these can negatively impact athlete’s health and performance. Furthermore, athletes who follow a plant-based diet consume about 70% of the protein that their omnivorous counterparts consume (Clarys et al., 2014), which may not be sufficient depending on one’s exercise regime and fitness goals.

Importance of Tracking, Supplementation and Fortification

Whatever diet you adopt, or even if you are an omnivore, there is a chance that your micro and macronutrient intake may result in some insufficiencies in the long run. If you opt for a plant-based diet, you have good chances of having to deal with B12, choline, iron and omega-3 deficiencies. It’s equally important that your calorie and macronutrient intake matches your exercise regimen and fitness goals. To keep the micronutrient levels in check, I would highly recommend getting your blood work done on a regular basis. It’s the best way to see how the diet patterns that you adopt translate to micronutrient levels, and it can help identify problems in their infancy or prevent them becoming problems in the first place. It is probably clear by now that for anyone following a plant-based diet consistently, it’s extremely likely that they will have to rely on supplementation and/or fortification for some, or all, of the micronutrients listed above. There is absolutely nothing wrong with that. If you are plant-based, please don’t insist on eating 100% naturally! Get some high-quality supplements, even if it were just for prevention, and your body will thank you for that. Do some research on which supplements to choose – lately there are plenty of them on the market and many come wide widely varying micronutrient levels or levels that are well beyond what you would need. Similarly, and in particular if you live an active lifestyle, you should get a good sense of the amount of calories and macronutrients you are digesting, and whether this matches your expenditure and goals. There are tools that can be used to calculate how many calories do you burn at your maintenance, given your exercise patterns. Look online for TDEE, total daily energy expenditure, calculator and use a few of them and take an average for more robust estimate. If you have somewhat smart bodyweight scale, it can give you pretty good estimate as well. Next, it’s mandatory to track the calories and specific foods that you are eating consistently, at least for some limited period. It’s not that long ago that I tried it for the first time, and I was very surprised with the result. I was on average eating about 30% less calories than I thought! Doing this will also help you understand whether you are meeting your macronutrient needs. Besides these ‘smart’ calculators, it is important to check in with your energy levels. If you feel low, make sure you are getting adequate sleep. If that is in check, look at decreasing intensity or frequency of your exercise (more rest) or increasing calorie input. Finally, if you are very active and plant-based, there is a chance you may be running too low on protein intake and then you would either want to adjust your diet or look for some high-quality vegetarian or vegan protein powder (again, nothing wrong with that!)

Plant-Based Diets for the Environment

Many people opt for plant-based diet to limit their environmental impact. All evidence suggests that this is a step in the right direction, yet the situation is certainly not black and white. How much of a positive impact on the environment will you have, if any, will depend on the individual products you consume on regular basis. Did you, for example, know that some types of cheese will have double to triple the emission footprint of chicken meat? Or that coffee and chocolate have similar emission footprints as some types of beef? ( Furthermore, choices other than dietary ones can have a larger impact on the environment. Opting to live without a car, skipping one long-haul flight per year or moving over to renewable sources of energy can have double to triple the positive impact of going plant-based. Better home insulation, using more public transport or opting to live without a pet all have comparable effects to becoming plant-based (Ivanova et al., 2020). And of course, not all plant-based diets are made equal, vegan diet is about twice as effective as general plant-based diet in this regard. Somewhat unpopular, having one less child seems by far the most effective climate impact mitigation strategy (Wines & Nicholas, 2017). However, I personally choose not to weigh the environmental concerns in this aspect too heavily, as there are tons of problems associated with the aging of society as well (hope to write on that in the future!).



  • Whatever diet you adopt, make sure it works for you: Does it make you feel good? Can you stick to it? Can you afford it? Doesn’t it feel overly restrictive?
  • Diet is a step in the right direction when aiming to improve health outcomes, but it won’t be (nearly as) effective if not accompanied by other lifestyle choices such as exercise, cigarette, and alcohol use, as well as mental health.
  • Even a plant-based diet can be an unhealthy one. Make sure to prioritize whole, unprocessed foods.
  • Maybe the largest benefit of plant-based diets is that they avoid some foods that are known to be causing disease, and that they facilitate adherence by becoming part of one’s identity.
  • Get your blood work done with some periodicity and track what you eat (at least for an initial period). Supplement accordingly.
  • Plant based diets can be safely followed by athletes and are even advantageous for some forms of exercise. Supplementation is very likely to be helpful.
  • Plant-based diets are only one the ways how to mitigate once environmental impact, and they are not the most effective ones. If the environment and health of our planet matters to you, please don’t stop here!

Thanks for reading everyone! Do you have any questions or thoughts spurred by the article? Did I forget to mention something obvious? I will be happy if you let me know in the comments section below!

The post is based on an online course by the National Academy of Sports Medicine that is on sale as part of their promo for the vegetarian awarness month (Oct’23). I can only suggest taking it if you are interested in the topic!