Nutrition Science Articles
Optimising a vegetarian/vegan diet
This blog was first written almost three years ago, so it’s time to give it a 2020 update!
First of all, let us just clarify why we didn’t relate the title of this blog to ‘plant based’ diets, and instead opted to talk specifically about vegetarian or vegan diets. In recent years these terms have been used interchangeably, but this is a mistake.
The standard definition of a plant based diet is any diet that places an emphasis on vegetables, fruits and wholegrains. Any diet that follows this pattern, whether it contains animal products or not, is plant based, but today we’re talking about diets that expressly do not contain animal based foods.
So with, that said, what kinds of diet ARE we talking about? In the scientific literature the catch-all term vegetarian is used to describe a wide range of diets, including:
- Lacto-ovo-vegetarian, the most common form where both dairy and eggs are still consumed
- Lacto-vegetarian, where dairy but not eggs are consumed
- Ovo-vegetarian, where eggs are consumed but not dairy
- Vegan, no animal products are consumed at all. This usually is a part of a broader lifestyle that avoids animal sourced goods
- Pescatarian, this diet includes fish and technically isn’t vegetarian, but many consider it a form of vegetarianism
Of course, worthy of mention here is the junk food vegetarian. You know the type; they barely eat vegetables or fruit and seem to live off of pizza and vegan pastries. They’re also really likely to have a sedentary lifestyle, preferring a Netflix binge to a lifting session at the gym. Why mention this?
According to the HRC, 1 in 5 vegetarians fail to adhere to a fully plant-based way of eating while 84% go back to eating meat, with family relationships being a major factor in this (1). As noted by Norman and Klaus in 2019, the reason that someone cites for engaging in a vegan or vegetarian diet probably mediates much of this (2), with early work suggesting that those adopting a vegan diet for ethical reasons have greater convictions (3), but also by definition less of an interest in the nutrition/health aspect of the lifestyle choice.
Let’s assume, however, that whatever your initial reason was for adopting a vegan or vegetarian diet, you now find yourself interested in doing so while improving or at least safeguarding your health. What is critical for you to know?
The first thing we need to say is that any diet which restricts food choices significantly is more likely to lead to micronutrient deficiencies if proper planning is not in place, be that diet vegan, carnivore, or anything in between. Vegan diets tend to be insufficient for the very young, pregnant women, or the very old without supplementation (2), and in general vegans are more likely to fall short on Vitamin B12 and Iron intakes (4), as well as showing low serum levels of Omega 3 fatty acids (5). Why is this the case?
B12 is a vitamin synthesised primarily in the gut of ruminants like cows and sheep, so the best source for it is animal products. Many vegans take a B-12 supplement, however, which is cheap and effective, and a lot of products are fortified to help out, too. Omega 3 is a tricky one if you are a vegan because the main source of the two useful fatty acids, EPA and DHA, is fish. These aren’t available in plant based sources of omega 3, where instead you find ALA (when you see nuts or seeds that are labelled as being high in Omega-3, this is the fatty acid present). ALA must be converted to EPA and DHA before it’s useful, and the conversion rate is extremely low, so supplementation with algae based supplements is recommended.
Finally, iron sufficiency can also be achieved on a vegan diet without supplementation but care needs to be taken to include rich sources like lentils and chickpeas regularly. If in doubt, supplementation is effective.
Once you have looked at your micronutrient needs, you’ll need to improve the balance of your diet. If you are currently transitioning from a healthy omnivorous diet to a vegetarian diet and have a basic understanding of nutrition there’s not all that much for you to do here as things are basically the same. There is no metabolic advantage to eating a vegan diet, calories still count and you still need protein, carbohydrate and fat.
If you are conscious about body composition or sporting performance, this becomes even more important. Protein, fats and carbohydrate requirements don’t change for an athlete.
- Protein: Aim for around 1.6 - 2.2g per kg
- Fats: Aim for around 0.5 – 1.5 g per kg
- Carbs: Eat according to personal preference and exercise mode
When you first make the switch from a diet that contains a lot of animal products to one that contains few or none, this can be a stumbling block. Many plant based sources of protein have a comparatively low protein density or an incomplete amino acid profile.
Amino acids are the building blocks of protein with leucine being the most important for muscle growth. Most plant-based proteins are low in leucine and one or more of the other essential amino acids – they contain all of them, but not in a ratio ideal for human use, especially muscular hypertrophy. For this reason, it’s necessary to combine protein sources throughout the day. No, you don’t have to combine them in every meal, so long as you get a good mix of pulses, wholegrains, nuts and seeds you should be covered.
A note for vegans who are aiming to get really jacked; there is an argument that plant based proteins are simply less effective and that aiming for a slight increase above recommended levels of around 10-20% might be favourable, as might combining protein sources meal to meal in order to get a good (3-4grams) dose of leucine. The Leucine content of various foods will not be on the label, but you can find that information quickly enough using nutritiondata.self.com.
Vegetarian protein sources
If you are a lacto-ovo vegetarian you can have eggs and dairy which makes it easier to get your leucine in. Here’s the amount of protein per typical serving of lacto-ovo foods.
- Eggs (about 5-8 g per egg depending on the size)
- Cheese (about 20-30g per 100g but also high in fat and calories)
- Yoghurt (about 5-10g per 100g with true Greek or Nordic yoghurts having the highest protein content)
- Milk (about 5g per 100ml)
There are many meat substitutes available, and while these aren’t to the liking of every vegetarian, these will definitely add variety and essential complete protein to your diet. The range of these is now broadening with the popularity of the vegan movement, and the quality has skyrocketed in the last 18 months. Some examples include:
- Quorn (about 15g per 100g) - Quorn may not be suitable for vegans so read the label
- Tempeh (about 19g per 100g)
- Soy meat (around 26g per 50g serving) this makes a great alternative to mincemeat in dishes like spaghetti bolognaise or chilli con ‘carne’
- Seitan (about 75g protein per 100g)
If these aren’t to your liking and you don’t eat eggs or dairy, all is not lost because you have plenty of natural plant foods available. Nuts and seeds usually have a decent protein content but are also high fats, so be mindful of the calories:
- Hemp seeds* (about 30g protein and 45g fats per 100g)
- Chia seeds* (about 17g protein and 31g fats per 100g)
- Flax seeds (about 18g protein and 42g fats per 100g)
- Sunflower seeds (about 21g protein and 52g fat per 100g)
- Peanuts (about 26g protein 42g fats per 100g)
- Almonds (about 21g protein and 49g fats per 100g)
- Cashews (about 18g protein and 44g fats per 100g)
- Walnuts (about 18g protein and 65g fats per 100g)
Pulses and legumes are usually about 60% carbohydrate:
- Lentils (about 9g protein and 20g carbohydrate per 100g)
- Chickpeas (about 9g protein and 26g carbohydrate per 100g)
- Black beans (about 8g protein and 24g carbohydrate per 100g)
- Adzuki beans (about 8g protein and 26g carbohydrate per 100g)
- Edamame beans* (about 11g protein and 10g carbohydrate per 100g)
- Baked beans (about 6g protein and 22g carbohydrate per 100g)
- Tofu (about 8g per 100g)
While wholegrains are mostly sources of carbohydrates and fibre (as well as some important micronutrients) they do contain small amounts of protein to help you top up. Some have a complete amino acid profile but many grains also contain gluten so if you are unfortunate enough to have a clinical intolerance to gluten be aware of which grains contain gluten.
- Wheat* flour (about 10g protein and 76g carbohydrates per 100g)
- Buckwheat flour** (about 11g protein and 75g carbohydrate per serving)
- Cooked quinoa** (about 4g protein and 21g carbs per 100g)
- Whole wheat bread* (about 10g protein and 49g carbohydrate per 100g)
- Rye bread* (about 9g protein and 48g carbohydrate per 100g)
- Oats (about 17g protein and 66g carbohydrate per 100g)
* Denotes complete amino acid profile.
** Denotes gluten content.
A word on fibre
Fibre is obviously important for your digestive health and a number of other functions in the body. Following a plant based way of eating means that, with all those veggies, fruits, pulses, wholegrains and seeds in your gut you will be getting a lot of fibre. 25-35g of fibre per day is optimal for most people, many vegans will struggle to stay below 50g but that’s not a problem and, if you can handle it without too much discomfort there is no defined upper limit for fibre intake. Just be aware, if you are newly transitioning to a plant based diet you might want to keep an eye on this and bring it up over a few weeks rather than jumping up from 25 to 50g per day.
Not everyone likes using protein powder but they are a must have addition to your pantry if you are serious about performance nutrition. Ove-lacto and lacto vegetarians can use whey assuming that you have no issues with digesting dairy. Lactose intolerance varies depending on historical diets, for example only 5% of northern Europeans are lactose intolerant, while some African communities have seen incidences as high as 90% (6). If you have an inability to digest dairy, you’ll likely know by now.
There are good vegan alternatives to whey protein which contain very similar amino acid profiles but are often grainy and don’t mix well. They often taste bad as well. Plain pea or rice protein (or a combination of both) are decent but taste awful on their own so mix them with other flavours, like chocolate almond milk, or save them for baking.
Flavoured vegan protein powders are usually sweetened with stevia which adds a mild aniseed flavour that isn’t to everyone’s liking. We think that we have found a smooth blend that tastes great. The reason it took us so long to launch our Awesome Supplements Vegan Protein blend was that we wanted the texture a flavour to be the best it possibly could and we think we’ve cracked it.
Like we say, protein powders aren’t a must but they allow larger athletes with a high protein need to hit their targets and, yes you can get ripped as a vegan but you might have to include a couple of shakes or add protein powders to your soups, sauces, granola, cakes, etc. to be able to hit those levels.
You absolutely can eat a balanced and healthy plant based diet and still hit your performance nutrition goals. It might be that you find that you need to go a little higher on either fats or carbs and a little lower on protein but, with a little practice, you shouldn’t have too much difficulty getting the balance right.
All the same rules regarding thermodynamics and energy balance apply. Set your macronutrients (if you are following a macro diet) using the same grams per kg recommendations.
Protein can be a bit tricky and powders may become an essential ingredient in your kitchen but we have you covered there.
One thing is for sure, you will have no issues getting more than adequate amounts of fibre in your diet and this can only be a good thing for the integrity of your gut microbiome and overall wellbeing.
- HRC (2014). Study of Current and Former Vegetarians and Vegans. 1st ed.
- Norman, K. and Klaus, S. (2019). Veganism, aging and longevity. Current Opinion in Clinical Nutrition and Metabolic Care, p.1.
- Hoffman, S., Stallings, S., Bessinger, R. and Brooks, G. (2013). Differences between health and ethical vegetarians. Strength of conviction, nutrition knowledge, dietary restriction, and duration of adherence. Appetite, 65, pp.139-144.
- Medawar, E., Huhn, S., Villringer, A. and Veronica Witte, A. (2019). The effects of plant-based diets on the body and the brain: a systematic review. Translational Psychiatry, 9(1).
- Burdge, G., Tan, S. and Henry, C. (2017). Long-chain n-3 PUFA in vegetarian women: a metabolic perspective. Journal of Nutritional Science, 6.
- Lactose intolerance. [online] Genetics Home Reference.