Last time, I looked at ‘vegetable’ oils; in this post I’ll take a look at ‘vegetable’ protein. (Again, the term ‘vegetable’ is being used as a modifier rather than as an indicator of the source of the protein). ‘Vegetable’ proteins come from grains and legumes
As a student, I was, for a while – gasp – a vegetarian. A crap one, with a raft of vague reasons why, but a vegetarian nevertheless. We often feasted on meals made with TVP, textured vegetable protein, available in our local ‘health food’ shop. I can laugh about it now, but in those days, I think we thought that we were ‘making a difference’ as well as getting our protein. (We were making a difference to our health, but not in the way we expected). TVP is made from soy that has not been fermented, and that key aspect of its production is responsible for a lot of bother. I think I’ll devote a whole post to soy, so I’ll skate over it here. But suffice to say that it is still widely believed that protein derived from legumes is appropriate, nay good for you.
The human body can make fat from sugars – don’t we just know it – and sugars from fat, and both those nutrients are used as fuel. We can’t create protein, though, nor is it a fuel source under normal circumstances, so we have to eat it in order for it to do its job of rebuilding muscle cells, bone cells, skin cells, hormones, enzymes and so on.
Adult humans can live for ever (well, you know what I mean) without so much as touching carbohydrates; we can live for a long time without eating fat, depending on how much we have stored – months, possibly; but our time without eating protein is limited to around 10 weeks because we don’t store it. So to say that it is a very important nutrient is an understatement. We need to get it right.
There are two main issues with plant-based protein for humans: getting all the essential amino acids, ‘bioavailability’ and the volume to be eaten to hit your daily requirement. Three, three main issues.
Bioavailability. If a food item contains a given nutrient, it doesn’t automatically follow that we can absorb it. Legume protein is 70% digestible, while meat protein is 94% digestible.
Amino acids. There are nine essential amino acids, and they are all present in meat, but almost no plant proteins have all nine.
Example: according to NutritionData, kidney beans have an ‘amino acid score’ of 89, where 100 is the benchmark, a complete or high-quality protein. One 177g serving provides 31% of one’s daily requirement. By comparison, rib-eye beef steak is given an amino acid score of 144, and providing 183% of the daily protein requirement in one serving. The serving sizes quoted differ massively, 177g of beans to 454g of steak, but we can do a little bit of maths to get a picture. So – volume issue – you’d need to eat three 177g servings of kidney beans – 531g, or about two and a half typical cans – to get close to the daily requirement of a protein that we can’t be certain will be absorbed in its entirety and which lacks essential amino acids. Yet 248g of steak – a fairly normal-to-large size – gives you all you need. Eating one big steak every day is a pleasure, a blessing, a privilege. Eating two and a half cans of kidney beans every day seems more like torture, plus you’d have to find the other amino acids somewhere too! And stock up on toilet paper.
Trying to get your protein from plant sources is dodgy on many levels: absorption is compromised by the presence of fibre, and can also be compromised, as in the case of soy, by elements of the legume itself preventing absorption; not all nine essential amino acids are present in all vegetable proteins, so there is a risk of missing out on some vital nutritional elements. You need to eat quite a lot of, say, as above, kidney beans, and that means a higher carb intake, and that means higher insulin levels, and that means higher fat storage…
Protein powders made from vegetable products are, according to a recent test, much more likely to have toxins absorbed from the soil, since plants are very good at, er, absorbing stuff from the soil. The Clean Label Project completed a study of 134 protein powder products from 52 brands. Products were screened for over 130 toxins including heavy metals, BPA, pesticides, and other contaminants with links to cancer and other health conditions. They were tested and reviewed by a third party analytical chemistry laboratory.
Conclusion: plant-based proteins have poor bioavailability; it is hard to get all nine essential amino acids from them; large amounts must be eaten to get daily protein requirements. Here’s an extra thought – vegetable protein usually comes neatly packaged with PUFAs, now thought to be carcinogenic, a cause of global inflammation and more. Here’s an extra, extra thought – the most commonly allergenic food substance for humans is gluten, a protein found in grains. There’s really no reason to try to rely on plant-based proteins, whether from food or from the powdered variety (no matter how well it’s marketed).
The protein we have evolved to work with is meat. It comes packaged with fat for fuel, has all the amino acids, doesn’t cause high insulin levels and is nutrient-dense. It has been tried and tested for many tens of thousands of years.
Lift weights (kettlebells, really) and eat meat. Simples.