0021 – From vegan to carnivore, and everything in between (part I)
One of the top 10 health-related internet searches in 2019 was “what is keto”. In the past couple of months, the spotlights have shifted to vegans and carnivores, who have been intensely debating about which diet is the best for our health and the environment. Somewhere in the middle, the vegetarians, paleo, keto and other omnivores count the points and shake their head. Should it really be one size fits all?
Enough controversy! Let’s examine the question from a different angle. What do they agree on? What are the foundations of a nutritious healthy diet? What foods should be avoided and which ones can be fine, depending on individual circumstances?
We are all different, with different physical activity levels, different health issues, personal objectives, genetic predispositions... Even our culture, religion, values and socio-economic status can influence what we eat.
In this article, I review these diets and a few issues to consider to optimise their nutritional value: vegans and vegetarians in part I, paleo, keto and carnivores in part II.
First of all, who eats what?
Let’s start by a few general definitions, recognising that each diet can have many variations and that this list is by no means exhaustive and only represents a few of the most popular diets.
Vegans do not eat animal-derived products. They have a plant-based diet and do not eat meat, fish, eggs, dairy products, honey, nor any other foods or drinks containing animal products.
Vegetarians have a plant-based diet, but also include animal-derived products (such as eggs and dairy products) as long as no animal was killed or harmed in the process.
Vegans and vegetarians do not exclude processed foods from their diet, although many are health conscious and prefer to eat fresh unprocessed produces, sometimes organic.
The paleo diet includes the foods that our ancestors used to eat: animals and plants that were available before the advent of agriculture. The paleo menu consists in meat, fish, eggs, vegetables, roots and tubers, fruits, nuts, seeds, herbs, spices and unprocessed oils. The quality of the food is very important, with a strong preference for organic produces and pasture-raised animals that are fed their natural diet (i.e. not fed with grains, hormones, antibiotics...). The paleo diet excludes grains (except wild varieties), cereals, legumes, processed foods, added sugar, soft drinks, and usually dairy products.
The ketogenic or "keto" diet is very low in carbohydrates ("carbs") and high in healthy fats. Very low carbs mean no sugar, no starchy vegetables, no grains / cereals / legumes, very little fruits (mostly berries). Carbs are limited to green or non-starchy vegetables, salads, herbs and spices and to about 50g per day. 70% of the calories come from healthy fats such as avocados, olives, nuts, coconut and their oils, seeds, butter, full fat dairy products and fatty meat. Proteins are kept to a moderate level (about 75 to 160g), from meat, fish and eggs. A well-formulated keto diet includes a variety of fresh produces, but unprocessed and low carbs. It is not meant to be limited to eggs, bacon, cheese and desserts made of almond meal and sweetener.
Carnivores only eat animal products: beef, chicken, pork, lamb, turkey, game meats, organ meats, fish, butter and a small amount of heavy cream and hard cheese. They do not eat any vegetables, fruits, grains, legumes, nuts, seeds, nor any herbs or spices. In theory, beverages should only include water and bone broth, but many find it difficult to give up on their coffee, tea or diet sodas.
What are the reasons for adopting a specific diet?
The main reasons revolve around human health, animal welfare and environmental concerns. The "dieters" disagree on what harms the environment and what type of food is the best for our health, but they agree – to various degrees – that modern processed foods and conventional farming are bad for us and for the planet.
Conventional farming include Concentrated Animal Feeding Operations (“CAFO”) and extensive mono-cultures. CAFO are very crowded factories that feed animals with GMO corn and soy beans, same species meat, animal waste, plastic, hormones and antibiotics. Extensive mono-cultures rely heavily on pesticides, herbicides and fungicides and deplete the soils. Those who are health conscious would like to see less subventions to GMO crops and to the sugar industry and more support to small organic farmers.
Whatever the diet is, there is also a general agreement that processed foods and beverages should be avoided for many reasons: they typically contain added sugar, processed vegetable oils, preservatives, colouring, emulsifiers, thickeners and other food additives that are all harmful for our waistline and our health. See my blogs on sugar and processed oils for more information.
In addition to health and environmental concerns, other religious, cultural and ethical beliefs or values can determine the adoption of a certain diet. However, from a pure health perspective, whether grain, cereals, legumes, fruits, vegetables, dairy products, meat, fish and eggs should be consumed and in what proportion shall depend on individual tolerance for these products.
Vegans and vegetarians generally count on the plants vitamins, minerals, antioxidants and fibres, as well as on their low levels of saturated fats and cholesterol to optimise their health.
On the other hand, plant-based food can be problematic for certain people, due to anti-nutrients and other compounds that can trigger various digestive issues and health conditions. Some people cannot tolerate gluten or lectins for instance. Other have sensitivities to nightshades or fermentable foods. This is typically why carnivores choose to eliminate all plants from their meals, to alleviate symptoms like diarrhea, bloating, gas, abdominal pain or worse.
Keto enthusiasts usually adopt a ketogenic nutrition to get rid of their cravings and addiction to sugar, to lose fat, reduce digestive or skin issues, improve brain clarity, reduce inflammation and the risk of many modern diseases (such as cancer, Alzheimer's and Parkinson's for instance).
Those who choose a paleo nutrition want to maximise their health by eating the food that we have genetically evolved to eat and that is optimised for our body. They also want to stay away from "man-made" processed foods that contain so many harmful ingredients. Some variations of a paleo diet are adopted by people suffering from auto-immune conditions (such as Celiac, Hashimoto's, rheumatoid arthritis, lupus, multiple sclerosis...) or other disorders (ADHD, autism, anxiety, depression...).
Last but not least, the majority of omnivores don’t really think about all this and are more interested in taste and convenience.
How vegans and vegetarians can optimise their diet
Some key nutrients can only be obtained in sufficient bio-available amounts from animal products. This is why vegans and vegetarians should eat a large variety of foods and take a few supplements to optimise their nutrition and long term health. This section explains how to address the most common deficiencies and issues with plant-based diets.
Vitamin B12 is one of the most common deficiencies found in vegans and vegetarians, as it is mostly found in animal products. This vitamin is necessary for proper nervous system and brain function, as well as for the synthesis of energy in our mitochondria. Vegans can get some B12 in chlorella, algae, mushrooms, fermented soy products and fortified foods (breakfast cereals, plant milk and nutritional yeast). Vegetarians can get a bit more from eggs, yoghurt, cheese and milk. However, supplementation is still likely to be needed in many cases.
Vitamin D is the other most common deficiency among vegans and vegetarians, especially for those who don't spend a lot of time outside or have a darker skin. Plant sources of vitamin D include wild mushrooms (exposed to UV light, not mushrooms grown in the dark), beans, broccoli and leafy greens, but in low amounts. Vegetarians can also get some vitamin D in pasture-raised egg yolks (the hens must spend time roaming outdoors) and fatty fish (for the pescatarians). Regular sun exposure is by far the best way to generate optimal vitamin D levels. The National Institute of Health recommends exposing face, arms, legs or back to sunlight for about 30 minutes twice a week, without sunscreen. However, the optimal level of sun exposure depends on the location, season, time of day, pollution, age and skin tone, and supplementation might still be required in some cases.
Iron can be found in heme and non-heme forms. The non-heme iron found in plants is much less absorbable by the body than the heme iron from meat, and its absorption is inhibited by whole grains, legumes and nuts that contain phytic acid and by tea, coffee and cocoa that contain tannins. This is why vegans are advised to aim for 1.8 times the normal recommended daily intake. Vegans and vegetarians should eat plenty of iron-rich foods such as soy, beans, peas, nuts, seeds, green leafy vegetables, cruciferous vegetables, dried fruits, in combination with vitamin-C rich foods (citrus, capsicums, broccoli, kiwis, tomatoes...) to increase absorption. Soaking, sprouting or fermenting these foods also improves the absorbability of iron. You can still drink your tea, coffee or eat dark chocolate, but just away from iron-rich meals. Note that iron supplementation is only recommended if a deficiency has been identified by a blood test, as too much iron can be toxic.
Calcium intake is usually low in vegans and its bio-availability can be affected by oxalates and phytic acid. It can be found in low-oxalate foods such as bok choy, broccoli, Chinese cabbage, collards, kale, okra, turnip greens, mustard greens, watercress, chickpeas, mushrooms and soy products. Fortified soy milk, sesame seeds, almonds and beans can contribute as well but with a lower bio-availability. Calcium is generally not an issue for vegetarians who consume dairy products and eggs.
Zinc deficiency is also common due to the inhibition of its absorption by phytic acids (again!) and fibres. Vegans and vegetarians should increase the standard recommended daily intake by 50%. Legumes, soy, nuts, seeds, wheat germ and whole grains are all rich in zinc and zinc absorption can be improved by soaking or fermenting these foods to reduce their phytic acid levels. For many, zinc supplementation may still be required.
Iodine is mostly found in fish, seafood and dairy products, but can also be obtained in vegan-friendly iodised salt, seaweed and sea vegetables to avoid deficiency.
Certain plant-based foods can cause digestive issues (gut inflammation, constipation, bloating, diarrhea...) in sensitive people, as well as skin and mood issues, brain fog or even more serious health conditions. This can be due to various anti-nutrients (such as lectins, gluten, phytates and saponins) and other compounds found for instance in grains, nightshades, FODMAP foods, soy, nuts or seeds. Anti-nutrients are natural toxins that the plants manufacture to defend themselves against predators and disease-producing micro-organisms. They can inhibit the absorption of vitamins and minerals, compromise the digestive and immune functions and promote inflammation. If you are vegan or vegetarian, keep in mind these common symptoms and check whether they might be relevant to you.
Certain forms of lectins can damage the lining of the small intestine, allowing foreign proteins to infiltrate the bloodstream. The body creates antibodies to get rid of them (clever!), but as lectins are similar to other healthy proteins found in the body, the antibodies can end up attacking the bad and the good proteins. Lectins can also trick the body into integrating them into routine functions, a process called molecular mimicry. This can result in diarrhea, gas, bloating, heartburn, irritable bowel syndrome ("IBS"), celiac disease, fibromyalgia, allergies, insulin resistance and more. The good news is that lectins can be reduced or eliminated by cooking at high heat or high pressure. They are found in the highest amounts in legumes, nightshades, dairy products and grains (such as barley, quinoa, and rice).
Gluten is a form of lectin but deserves a specific mention, as somewhere between 8% and 33% of the population (experts' estimates vary!) is sensitive to gluten, usually without knowing it. Typical symptoms include digestive issues (bloating, IBS-like symptoms, diarrhea, constipation and gas), behavioural issues, fatigue, headache, joint or muscle pain, leg or arm numbness, brain fog, skin inflammation or rash, depression, anxiety, anaemia, reproductive problems, acid reflux and autoimmune diseases. The list is sadly very long. Gluten is found in grains such as wheat, barley, rye and in many processed foods, such as bread, pasta, cereals, baked goods, snacks, sauces, beverages... As so many of us experience bloating and cravings after eating gluten, you may want to try going gluten-free for a few weeks to see whether you feel better.
Phytates or phytic acid are antioxidants found in whole grains, legumes, nuts (Brazil nuts, almonds, walnuts), cocoa powder, coconut and seeds. They bind to minerals (iron, zinc, magnesium, calcium...) in the digestive tract and interfere with their absorption. They have healthy anti-oxidant and anti-inflammatory benefits but excessive intake can lead to nutrient depletion. You can significantly reduce phytic acid contents of foods by cooking, soaking, sprouting or fermenting them.
Saponins are found in all legumes (beans, peas, lentils, soy, alfalfa), in certain grains (amaranth, buckwheat and quinoa) and seeds (chia and flax). They can enter the bloodstream in people with leaky gut and compromise the ability of red blood cells to process oxygen, increase the risk of bacterial infection, allergies, and autoimmune disease. Cooking does not destroy saponins but soaking and fermenting does.
Oxalates either bind to calcium during digestion and are eliminated in the stools or travel to the kidneys and are eliminated in the urine. If there are too many oxalates and too little liquid in the urine, they can form kidney stones (ouch!). Oxalates can also weaken bones, trigger joint and eye pain, as well as skin rashes. If you suffer from any of these symptoms, consider reducing oxalate-rich foods: spinach, beet greens, rhubarb, sweet potatoes, kale, chocolate/cocoa, certain nuts and seeds (almonds, peanuts, sesame, chia), turmeric, cinnamon, black pepper, parsley, soy products, dry fruits, beans, tea and coffee. Do not eat these foods every day nor in large amounts, stay well hydrated, add lemon juice to your water, reduce your salt intake, eat calcium rich-food or supplement with calcium citrate.
Nightshades contain alkaloids, toxic chemical compounds that protect the plants from moulds and pests. They include white potatoes, tomatoes, eggplants, capsicums, chili's, cayenne, red pepper, goji berries... People who are sensitive to nightshades may experience digestive issues (bloating, gas, diarrhea), skin rashes, nasal congestion, achy muscles and joints and inflammation.
Salicylates are found in foods such as berries, oranges, pineapples, apricots, broccoli, cucumbers and zucchini and in medication like aspirin. They are harmless for most of us but can trigger asthma, nasal discharge and digestive issues in sensitive people.
Histamine is present in eggplants, spinach, tomatoes, avocados and fermented foods or drinks and is also produced by our body as part of an immune response. Excess levels of histamine or an inability to break it down can cause symptoms like hives, abdominal pain, asthma and headaches, among others.
FODMAP (Fermentable Oligosaccarides, Disaccarides, Monosaccarides and Polyols) are fermentable sugar molecules found in fruits, vegetables, grains and dairy products, that can cause digestive upset in people with Irritable Bowel Syndrome. Most of us don't have any issue with FODMAP but in certain people suffering from IBS, they can cause the intestinal wall to stretch, resulting in pain, bloating, excessive gas, diarrhoea or constipation.
Last, for vegetarians, other common foods that can create sensitivities include dairy products and eggs (especially the whites).
As with any diet, an appropriate balance of macronutrients (proteins, carbohydrates and fats) should be maintained for optimal health. As plant-based foods are generally higher in carbs and lower in proteins and fats than animal-source foods, vegans and vegetarians should ensure they get an adequate amount of proteins and healthy fats, whilst avoiding excess carbs.
Protein intake is often low in vegan diets, which can result in the breakdown of muscle tissues. The general recommendation for healthy adults is between 1.5 and 2g of protein per kg of ideal body weight (0.7 to 0.9g per pound), depending on age and physical activity level. Many plant-based protein sources do not contain all the essential amino acids and plants anti-nutrients and fibres can interfere with their absorption. Vegans should consume a variety of grains, legumes, soy products, nuts and seeds to ensure that all the amino acids are present in adequate quantity. In particular, soy, lupines, spinach, buckwheat, quinoa, amaranth and hemp seeds are complete proteins containing all the essential amino acids. Vegetarians can get additional proteins from eggs and dairy products. Alternatively, consuming a high-quality protein powder can ensure protein needs are met. Just make sure the protein powder doesn't contain nasty additives, GMO products or heavy metals such as arsenic.
Healthy fats and essential fatty acids also tend to be lower in vegan and vegetarian diets. Good cholesterol is needed for brain and mood health, hormones, neurotransmitters and also to allow the absorption of fat-soluble vitamins (A, D, E and K). Eating plenty of healthy fats such as avocados, olives, olive oil, coconut, nuts and seeds is an easy and delicious way to address any deficiency.
Balanced omega-3 and omega-6 fatty acids levels are paramount for brain health and to reduce the risk of many chronic diseases that are so prevalent in our modern societies. Vegans and vegetarians are typically low in EPA and DHA (the 2 most important omega-3 found mostly in fatty fish and fish oil) and high in omega-6 (from processed foods, vegetable oils and margarine/fake butters). To balance your "omegas", limit your intake of processed foods and oils, and supplement with algae oil. Some plant foods (ground flax, hemp and chia seeds, as well as walnuts) contain another type of omega-3 called ALA, but less than 5 and 10% of ALA is converted to DHA and EPA, respectively. If you want to check whether your omegas are balanced, a simple blood test could give you the answer.
Excess consumption of carbohydrates can result in blood sugar imbalances, hunger and cravings, weight gain as well as other troublesome health issues. This is because dietary carbs trigger the release of insulin and excess insulin promotes fat storage, oxidation and inflammation, which increases the risk of obesity, diabetes, cancer and heart disease. Excess carbs can also lead to excess fibre intake, which can deplete nutrients and cause digestive issues (bloating, gas, cramping, diarrhea or even constipation). One option to check whether you carb intake might be harmful for your health is to do a blood test for HbA1c and fasting glucose levels.
In summary, if you are vegan or vegetarian, you can optimise your diet by eating a variety of fresh plant-based foods (as well as eggs and full fat dairy products for vegetarians), if possible locally sourced and organic, and by avoiding processed foods, soft drinks, processed vegetable oils, "fake" butter and "fake" meat. Test your blood for deficiencies and supplement with vitamins and minerals if needed.
Pay attention to how you feel. If you feel fatigued, experience gastrointestinal, skin or mood issues, brain fog or other conditions, talk to a qualified nutritionist to see how to adjust your nutrition for optimal health and well-being. If you think you might be sensitive to one type of food, consider eliminating it for a few weeks to see whether it makes any difference. A certain diet can work for you for a while and then stop working for no obvious reason: optimal nutrition is a constant balancing act.
Next week, I will cover diet optimisation for paleo, keto and carnivores. So, stay tuned for more!
This article is for educational purposes only. It is not a substitute for professional medical advice and is not intended to diagnose, treat, cure, heal or prevent any disease or medical condition. See full Disclaimer here. I encourage you to do your own research and to discuss with a qualified healthcare practitioner the options that could work the best for your specific circumstances.
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