The primary rules of Paleo:
- Thou shalt eat no Grains, closely followed by
- Thou Shalt eat no Legumes
Grains, and their also starchy relative, legumes, are the cause for all the world’s health woes, according to Paleo pseudo-science. Just try not to think about all those thin Asians with thriving civilisations built on the back of the rice grain, or of the Romans, fuelled by wheat and barley, or the Arabic Empires of the Middle Ages fuelled by barley and lentils, and the northern European civilisations fuelled by rye and wheat. No – Paleo lore says that grains and starchy lentils are the foods to avoid completely if you want to be healthy and slender.
What is the basis for these claims?
Beans and lentils are full of ‘anti-nutrients’ and starch
Every research study ever done in the world associates the consumption of legumes (beans, lentils and split peas) with longevity. And the more legumes eaten, the more healthy years people live.
In fact, legumes are the most important dietary predictor of survival in older people of all ethnicities than any other food.
Research shows that for every 20g of beans added to a diet daily, 7 – 8 years are added to life. 20g of beans is about 1 level dessertspoon. Most bean and lentil eaters eat way more than 20g in a day – a ½ cup serve weighs about 85g (in effect, adding 28 years to one’s life in a day!).
A diet that vilifies beans and lentils and puts them on the ‘NO’ list in order to justify a story about how early man apparently ate <see this Post> is utterly foolish, to say the least.
What is the reasoning for avoiding beans and lentils?
Beans and lentils contain
- phytates that block the absorption of zinc and some other essential minerals, and they contain
- starches which are purported to make us fat.
But what does the science say – or are these concerns just more of the story-telling?
Grains, beans, seeds and nuts are the foods highest in phytate. Phytates are the storage-department for minerals in plants and seeds. When phytates were first discovered they were originally viewed as ‘anti-nutrients’. Further study has shown that view to be largely incorrect. Phytates actually have many beneficial health effects.
- The phytates themselves have antioxidant and anti-cancer effects.
- Phytates reduce the glycemic effects of the foods they are present in.
- They also appear to bind toxic metals, reducing our absorption of these harmful substances.
- Some research indicates phytates may help to prevent kidney stones and the calcification of arteries.
If the blockage of zinc was such a big issue, why do the societies who eat the most legumes in their diets live the longest? Surely, if this ‘anti-nutrient’ effect of phytates was such an issue, such people who ate a lot of legumes would be the least healthy societies and would die youngest. Clearly, the health benefits of phytate-rich foods easily outweigh any apparently negative effects.
Viewing phytates as solely negative, and reason to abandon a food, is an outdated idea, no longer based on good science.
Is starch fattening?
No, and particularly not in legumes.
Most of the starch in a bean is ‘resistant starch’. This means it can’t be absorbed into the body. A very small amount of resistant starch (about 10%) gets broken down in the large intestine into medium chain fats which become fuel for the cells of the large intestine, but the rest passes through, doing magical things on the way.
Much of the rest of beans is soluble fibre – again, unable to be absorbed. Only about 1/3 of the listed calorie value of beans and lentils actually gets absorbed as calories for energy use inside the body.
In other words, of one serve of ½ cup cooked black beans, at 113.5 calories, only about 38 of those calories are actually absorbed as starchy calories to be used to produce energy in the Citric Acid cycle or stored in the muscles as glycogen. That’s small amount of calories for all the benefits and satiation beans give.
Avoid all grains. They are the worst foods!
Here we come to fad diet books.
The books, Grain Brain and Wheat Belly have a lot to answer for in terms of misleading the public with poor science. Both books put whole grains in the same boat as refined grains, mixing studies and making leaps of logic that the studies don’t show. Whole grains and starches are highly nutritious foods upon which all large civilisations were founded. They are inexpensive and contain many useful nutrients and plant proteins which do not promote cancer, unlike animal proteins. Furthermore, long term studies of large numbers of people do not find them to be the basis of weight gain. Have you ever seen a fat Asian person eating a traditional (non-Western) rice-based diet?
What about gluten?
The fear that these books have promoted about ‘gluten-intolerance’ is over-rated.
Less than 1% of any population has coeliac disease (an autoimmune disease whereby consuming gluten, the main protein in wheat, rye and barley leads to the destruction of the villi of the small intestine, fatally compromising food absorption.)
Fewer than 10% have what we call “non-coeliac gluten sensitivity”. Human bodies don’t have the enzymes necessary to fully break down gluten, and as a result, some peptides (molecules) pass into the bloodstream and can cause adverse health consequences in sensitive people. Such sensitivity is on a continuum, however, and while some need to avoid most gluten, most need to only avoid a certain amount at a time, which they must work out for themselves.
In controlled trials, where many people went gluten-free then were retested with capsules containing either gluten flour or a sugar pill (and no-one knew which they were getting, which is the only reliable way to discover true gluten intolerance), those receiving the gluten pill reported fewer cases of ‘bloating’ than those receiving the sugar-containing pill.
Many people go ‘gluten-free’ and experience weight loss, more energy and better health over all. Much of this may be attributed to the fact that stopping gluten also means stopping cakes, doughnuts, pies, biscuits, battered fish, white bread and most processed foods. This is a benefit, but the problem may have been all the sugar, fat and refined flour in these products, not the fact that they also contained gluten. Many studies implicate sugar, fat and refined flour with ill health and weight gain. Few studies implicate gluten with ill health and weight gain, and most studies actually show the opposite.
Clearly, a small percentage of people will benefit when reducing gluten in their diets, but gluten intolerance is not the overwhelming epidemic some popular Paleo-oriented books lead us to believe.
And I guess Einstein, Plato, Pythagorus and Leonardo da Vinci never knew that eating grain would damage their intelligence while living their lives as vegetarians.
What about phytates in grains?
As with legumes, grains contain phytate, but this does not appear to cause a problem in balanced diets. Phytates are effectively reduced through
- leavening (as with yeast bread – most bread we know) and
- soaking (as in soaking porridge oats or sourdough bread) and
- sprouting grains (as with sprouted breads or wheat grass).
These are the forms most of these products are eaten in the West. The main way that grain phytates have ever caused a zinc deficiency problem was in Syrian children from poor areas eating flat breads (unleavened) in large quantities and without sufficient minerals from other sources.
Cutting out legumes is nonsensical for anyone, and removing whole-grains from the diet without good reason is unnecessary for most of us.