Real Food VII: Lentils

Lentils are a healthy food that comes with a few caveats. They have more protein and less carbohydrate than any other legume besides soybeans and peanuts, and they contain a remarkable array of vitamins and minerals, particularly B vitamins. One cup delivers 90% of your RDA of folate, so between lentils and liver there's no need for those sketchy prenatal vitamins.

Lentils must be properly prepared to be digestible and nutritious! I can't emphasize this enough. We did not evolve eating legumes, so we have to take certain steps to be able to digest them adequately. As with all beans and grains, proper soaking is essential to neutralize their naturally occurring toxins and anti-nutrients. Anti-nutrients are substances that interfere with the absorption of nutrients. Soaking activates enzymes in the seeds themselves that degrade these substances. It also cuts down substantially on cooking time and reduces flatulence.

Phytic acid is an anti-nutrient that's abundant in beans, grains and nuts. It can dramatically reduce the absorption of important minerals such as iron, calcium, magnesium and zinc, leading to deficiencies over time. It may be one of the main reasons human stature decreased after the adoption of agriculture, and it probably continues to contribute to short stature and health problems around the world.

Lentils and other seeds also contain trypsin inhibitors. Trypsin is one of the digestive system's main protein-digesting enzymes, and seeds probably inhibit it as a defense against predators. Another class of toxins are the lectins. Certain lectins are able to bind to and damage the digestive tract, and even pass into the circulation and possibly wreak havoc. This is a short list of a few of the toxins found in beans and grains. Fortunately, all of these toxins can be reduced or eliminated by proper soaking. I like to soak all legumes for a full 24 hours, adding warm water halfway through. This increases the activity of the toxin-degrading enzymes.

Here's a method for preparing lentils that I've found to be effective. You will actually save time by doing it this way rather than cooking them without soaking, because they cook so much more quickly:

1. 24 hours before cooking, place dry lentils in a large bowl and cover with 2" of water or more.
2. After 12 hours or so, drain and cover the lentils with very warm water (not hot tap water).
3. Drain and rinse before cooking.
4. To cook, simply cover the soaked lentils with fresh water and boil until tender. I like to add a 2-inch piece of the seaweed kombu to increase mineral content and digestibility.

many thanks to *clarity* for the CC photo

Beans, Lentils, and the Paleo Diet

As we continue to explore the foods our ancestors relied on during our evolutionary history, and what foods work best for us today, we come to legumes such as beans and lentils.  These are controversial foods within the Paleolithic diet community, while the broader nutrition community tends to view legumes as healthy.

Beans and lentils have a lot going for them.  They're one of the few foods that are simultaneously rich in protein and fiber, making them highly satiating and potentially good for the critters in our colon.  They're also relatively nutritious, delivering a hefty dose of vitamins and minerals.  The minerals are partially bound by the anti-nutrient phytic acid, but simply soaking and cooking beans and lentils typically degrades 30-70 percent of it, making the minerals more available for absorption (Food Phytates. Reddy and Sathe. 2002).  Omitting the soaking step greatly reduces the degradation of phytic acid (Food Phytates. Reddy and Sathe. 2002).

The only tangible downside to beans I can think of, from a nutritional standpoint, is that some people have a hard time with the large quantity of fermentable fiber they provide, particularly people who are sensitive to FODMAPs.  Thorough soaking prior to cooking can increase the digestibility of the "musical fruit" by activating the sprouting program and leaching out tannins and indigestible saccharides.  I soak all beans and lentils for 12-24 hours.

The canonical Paleolithic diet approach excludes legumes because they were supposedly not part of our ancestral dietary pattern.  I'm going to argue here that there is good evidence of widespread legume consumption by hunter-gatherers and archaic humans, and that beans and lentils are therefore an "ancestral" food that falls within the Paleo diet rubric.  Many species of edible legumes are common around the globe, including in Africa, and the high calorie and protein content of legume seeds would have made them prime targets for exploitation by ancestral humans after the development of cooking.  Below, I've compiled a few examples of legume consumption by hunter-gatherers and extinct archaic humans.  I didn't have to look very hard to find these, and there are probably many other examples available.  If you know of any, please share them in the comments.

To be clear, I would eat beans and lentils even if they weren't part of ancestral hunter-gatherer diets, because they're inexpensive, nutritious, I like the taste, and they were safely consumed by many traditional agricultural populations probably including my own ancestors.

Extensive "bean" consumption by the !Kung San of the Kalahari desert

Instant Pot Electronic Pressure Cooker: Two Years Later

I've had several people tell me that the Whole Health Source post that changed their lives the most was one I published in 2012-- about a pressure cooker.

In 2012, I first reviewed the Instant Pot-- a "pressure cooker for the 21st century" that also doubles as a slow cooker and rice cooker (1).  Since then, we've used it more than 400 times, and it has saved us countless hours of kitchen drudgery.  It's indispensable for my current cooking style, and a major time saver for anyone who leads a busy life but still wants to cook wholesome food at home.  It's extremely satisfying to be able to put your ingredients into the Instant Pot, push a couple of buttons, do something else until it beeps, and then eat a healthy, inexpensive, and delicious meal.

Pressure cookers are one of the most time- and energy-efficient cooking tools, but electronic versions are even more efficient than traditional stovetop pressure cookers.  They're more time-efficient because you don't have to fiddle with them-- for example, adjusting the heat.  They're more energy-efficient because 1) they stop heating when the interior has reached the appropriate pressure, meaning that they're only using energy for part of the cooking process and they hardly vent any energy-wasting steam, and 2) they're insulated well enough that the sides never get hot.

I've used my Instant Pot for a wide variety of cooking tasks, and this is what it does best:

What I Eat

People often ask me what I eat.  I've been reluctant to share, because it feels egocentric and I'm a private person by nature.  I also don't want people to view my diet as a universal prescription for others.  But in the end, as someone who shares my opinions about nutrition, it's only fair that I answer the question.  So here we go.

In my food choices, I try to strike a balance between nutrition, cost, time efficiency, animal welfare, pleasure, and environmental impact.  I'm the chef of my household of two, and I cook two meals a day, almost every day, typically from single ingredients.  I prefer organic, but I don't insist on it.

Eggs from my hens

My diet changes seasonally because I grow much of my own food.  This started out with vegetables, but recently has expanded to staple foods such as potatoes, flour corn, and winter squash.  I also have a small flock of laying hens that turn table scraps, bugs, grass, and chicken feed into delicious eggs.

The primary guiding principle of my diet is to eat somewhere between a "Paleolithic"-style diet and a traditional agricultural/horticultural diet.  I think of it as a broad ancestral diet.  Because it's partially inspired by agricultural/horticultural diets, starch is the main calorie source.

My meals are organized around three food groups: a protein, a starch, and vegetables/fruit.  If any of those three are missing, the meal doesn't feel complete.  I'll start with those categories and move on from there.

Fat and Carbohydrate: Clarifications and Details

The last two posts on fat and carbohydrate were written to answer a few important, but relatively narrow, questions that I feel are particularly pertinent at the moment:

• Was the US obesity epidemic caused by an increase in calorie intake?
• Could it have been caused by an increase in carbohydrate intake, independent of the increase in calorie intake?
• Does an unrestricted high-carbohydrate diet lead to a higher calorie intake and body fatness than an unrestricted high-fat diet, or vice versa?
• Could the US government's advice to eat a low-fat diet have caused the obesity epidemic by causing a dietary shift toward carbohydrate?

However, those posts left a few loose ends that I'd like to tie up in this post.  Here, I'll lay out my opinions on the relationship between macronutrient intake and obesity in more detail.  I'll give my opinions on the following questions:

• What dietary macronutrient composition is the least likely to cause obesity over a lifetime?
• What dietary macronutrient composition is best for a person who is already overweight or obese?
• Is fat inherently fattening and/or unhealthy?

From the beginning

Losing Fat With Simple Food-- Two Reader Anecdotes

Each week, I'm receiving more e-mails and comments from people who are successfully losing fat by eating simple (low reward) food, similar to what I described here.  In some cases, people are breaking through fat loss plateaus that they had reached on conventional low-carbohydrate, low-fat or paleo diets.  This concept can be applied to any type of diet, and I believe it is an important characteristic of ancestral food patterns.

At the Ancestral Health Symposium, I met two Whole Health Source readers, Aravind Balasubramanian and Kamal Patel, who were interested in trying a simple diet to lose fat and improve their health.  In addition, they wanted to break free of certain other high-reward activities in their lives that they felt were not constructive.  They recently embarked on an 8-week low-reward diet and lifestyle to test the effectiveness of the concepts.  Both of them had previously achieved a stable (in Aravind's case, reduced) weight on a paleo-ish diet prior to this experiment, but they still carried more fat than they wanted to.  They offered to write about their experience for WHS, and I thought other readers might find it informative.  Their story is below, followed by a few of my comments.

This is your brain on pumpkin pie

Image credit: Evan Amos

Thanksgiving is a special time in the United States when we gather our loved ones and celebrate the abundance of fall with a rich palette of traditional foods.  Yet a new study suggests that the 6-week holiday period that spans Thanksgiving, Christmas, and New Year’s Eve accounts for most of our country’s weight problem (1).  Understanding this fact, and why it happens, gives us powerful insights into why we gain weight, and what to do about it.

Elina Helander, a postdoctoral researcher at Tampere University of Technology in Finland, and her colleagues set out to answer a simple question: how does a person’s body weight change over the course of the year?  To find out, they used internet-connected scales to collect daily body weight data from nearly 3,000 volunteers in the United States, Germany, and Japan.  After crunching the data, a striking pattern emerged: no matter what you celebrate, at any time of year, the holidays are likely to be your period of greatest weight gain.

Palatability, Satiety and Calorie Intake

WHS reader Paul Hagerty recently sent me a very interesting paper titled "A Satiety Index of Common Foods", by Dr. SHA Holt and colleagues (1).  This paper quantified how full we feel after eating specific foods.  I've been aware of it for a while, but hadn't read it until recently.  They fed volunteers a variety of commonly eaten foods, each in a 240 calorie portion, and measured how full each food made them feel, and how much they ate at a subsequent meal.  Using the results, they calculated a "satiety index", which represents the fullness per calorie of each food, normalized to white bread (white bread arbitrarily set to SI = 100).  So for example, popcorn has a satiety index of 154, meaning it's more filling than white bread per calorie. 

One of the most interesting aspects of the paper is that the investigators measured a variety of food properties (energy density, fat, starch, sugar, fiber, water content, palatability), and then determined which of them explained the SI values most completely.

What Properties Make a Food "Addictive"?

Although the concept of food addiction remains controversial, there's no doubt that specific foods can provoke addiction-like behaviors in susceptible people.  Yet not all foods have this effect, suggesting that it's related to specific food properties.  A new study aims to identify the properties that make a food "addictive".

Introduction

Is Meat Unhealthy? Part I

Introduction

At Dr. McDougall's Advanced Study Weekend, I had the opportunity to hear a number of researchers and advocates make the case for a "plant-based diet", which is a diet containing little or no animal foods.  Many of them voiced the opinion that animal foods contribute substantially to the primary killers in the US, such as heart disease and cancer.  Some of the evidence they presented was provocative and compelling, so it stimulated me to take a deeper look and come to my own conclusions.

No matter what the health implications of meat eating turn out to be, I respect vegetarians and vegans.  Most of them are conscientious, responsible people who make daily personal sacrifices to try to make the world a better place for all of us.

My Experience with Vegetarian and Vegan Diets

Is Meat Unhealthy? Part IX

Welcome to the last post in the series.  Time to summarize and wrap it up!

Respect

I respect each person's right to choose the diet they prefer.  This includes vegetarians and vegans, particularly because most of them make daily sacrifices to try to make the world a better place for all of us.  I'm an omnivore, but I sympathize with some of the philosophy and I often eat beans or lentils instead of meat*.

Our history with meat

Our ancestors have probably been eating some form of meat continuously for at least two hundred million years.  However, the quantity has waxed and waned.  The first mammals were probably largely carnivorous (insectivores).  Yet our primate ancestors went through a 60-million-year arboreal phase, during which we probably ate fruit, leaves, seeds, insects, and perhaps a little bit of vertebrate meat.  We only outgrew this phase in the last few million years, when we developed the tools and the brains to pursue prey more effectively.

During our 2.6 million-year stint as hominin hunter-gatherers, we ate an omnivorous diet, although we really have very little idea how much meat it contained (it probably varied by time and place).  Historical and contemporary hunter-gatherer cultures are all omnivorous, and typically eat significant to substantial quantities of meat, suggesting that our ancestors may have done the same.  Non-industrial agricultural populations eat as much meat as they can get, although they usually can't get as much as hunter-gatherers.

If there is such thing as a natural human diet, it is clearly omnivorous.

Meat, obesity, and chronic disease

Traditional Preparation Methods Improve Grains' Nutritive Value

Soaking or Germinating Grains

The most basic method of preparing grains is prolonged soaking in water, followed by cooking. This combination reduces the level of water-soluble and heat-sensitive toxins and anti-nutrients such as tannins, saponins, digestive enzyme inhibitors and lectins, as well as flatulence factors. It also partially degrades phytic acid, which is a potent inhibitor of mineral absorption, an inhibitor of the digestive enzyme trypsin and an enemy of dental health (1). This improves the digestibility and nutritional value of grains as well as legumes.

I prefer to soak all grains and legumes for at least 12 hours in a warm location, preferably 24. This includes foods that most people don't soak, such as lentils. Soaking does not reduce phytic acid at all in grains that have been heat-treated, such as oats and kasha (technically not a grain), because they no longer contain the phytic acid-degrading enzyme phytase. Cooking without soaking first also does not have much effect on phytic acid.

The next level of grain preparation is germination. After soaking, rinse the grains twice per day for an additional day or two. This activates the grains' sprouting program and further increases their digestibility and vitamin content. When combined with cooking, it reduces phytic acid, although modestly. Therefore, most of the minerals in sprouted whole grains will continue to be inaccessible. Many raw sprouted grains and legumes are edible, but I wouldn't use them as a staple food because they retain most of their phytic acid as well as some heat-sensitive anti-nutrients (2).

Grinding and Fermenting Grains

Many cultures around the world have independently discovered fermentation as a way to greatly improve the digestibility and nutritive value of grains (3). Typically, grains are soaked, ground, and allowed to sour ferment for times ranging from 12 hours to several days. In some cases, a portion of the bran is removed before or after grinding.

In addition to the reduction in toxins and anti-nutrients afforded by soaking and cooking, grinding and fermentation goes much further. Grinding greatly increases the surface area of the grains and breaks up their cellular structure, releasing enzymes which are important for the transformation to come. Under the right conditions, which are easy to achieve, lactic acid bacteria rapidly acidify the batter. These bacteria are naturally present on grains, but adding a starter makes the process more efficient and reliable.

Due to some quirk of nature, grain phytase is maximally active at a pH of between 4.5 and 5.5, which is mildly acidic. This is why the Weston Price foundation recommends soaking grains in an acidic medium before cooking. The combination of grinding and sour fermentation causes grains to efficiently degrade their own phytic acid (as long as they haven't been heat treated first), making minerals much more available for absorption (4, 5, 6, 7). This transforms whole grains from a poor source of minerals into a good source.

The degree of phytic acid degradation depends on the starting amount of phytase in the grain. Corn, rice, oats and millet don't contain much phytase activity, so they require either a longer fermentation time, or the addition of high-phytase grains to the batter (8). Whole raw buckwheat, wheat, and particularly rye contain a large amount of phytase (9), although I feel wheat is problematic for other reasons.

As fermentation proceeds, bacteria secrete enzymes that begin digesting the protein, starch and other substances in the batter. Fermentation reduces lectin levels substantially, which are reduced further by cooking (10). Lectins are toxins that can interfere with digestion and may be involved in autoimmune disease, an idea championed by Dr. Loren Cordain. Grain lectins are generally heat-sensitive, but one notable exception is the nasty lectin wheat germ agglutinin (WGA). As its name suggests, WGA is found in wheat germ, and thus is mostly absent in white flour. WGA may have been another reason why DART participants who increased their wheat fiber intake had significantly more heart attacks than those who didn't. I don't know if fermentation degrades WGA.

One of the problems with grains is their poor protein quality. Besides containing a fairly low concentration of protein to begin with, they also don't contain a good balance of essential amino acids. This prevents their efficient use by the body, unless a separate source of certain amino acids is eaten along with them. The main limiting amino acid in grains is lysine. Legumes are rich in lysine, which is why cultures around the world pair them with grains. Bacterial fermentation produces lysine, often increasing its concentration by many fold and making grains nearly a "complete protein", i.e. one that contains the ideal balance of essential amino acids as do animal proteins (11, scroll down to see graph). Not very many plant foods can make that claim. Fermentation also increases the concentration of the amino acid methionine and certain vitamins.

Another problem with grain protein is it's poorly digested relative to animal protein. This means that a portion of it escapes digestion, leading to a lower nutritive value and a higher risk of allergy due to undigested protein hanging around in the digestive tract. Fermentation followed by cooking increases the digestibility of grain protein, bringing it nearly to the same level as meat (12, 13, 14, 15). This may relate to the destruction of protease inhibitors (trypsin inhibitors, phytic acid) and the partial pre-digestion of grain proteins by bacteria.

Once you delve into the research on traditional grain preparation methods, you begin to see why grain-eating cultures throughout the world have favored certain techniques. Proper grain processing transforms them from toxic to nutritious, from health-degrading to health-giving. Modern industrial grain processing has largely eschewed these time-honored techniques, replacing them with low-extraction milling, extrusion and quick-rise yeast strains.

Many people will not be willing to go through the trouble of grinding and fermentation to prepare grains. I can sympathize, although if you have the right tools, once you establish a routine it really isn't that much work. It just requires a bit of organization. In fact, it can even be downright convenient. I often keep a bowl of fermented dosa or buckwheat batter in the fridge, ready to make a tasty "pancake" at a moment's notice. In the next post, I'll describe a few recipes from different parts of the world.

Further reading:

How to Eat Grains
A Few Thoughts on Minerals, Milling, Grains and Tubers
Dietary Fiber and Mineral Availability
A New Way to Soak Brown Rice

New Study: Is a Calorie a Calorie?

A new study in JAMA led by Dr. Cara B. Ebbeling and colleagues purports to challenge the idea that all calories are equally fattening (1).  Let's have a look.  When thinking about the role of calorie intake in body fatness, there are basically three camps:

1.    Calories don’t matter at all, only diet composition matters.
2.    Calories are the only thing that matters, and diet composition is irrelevant.
3.    Calories matter, but diet composition may also play a role.

The first one is an odd position that is not very well populated.  The second one has a lot of adherents in the research world, and there’s enough evidence to make a good case for it.  It’s represented by the phrase ‘a calorie is a calorie’, i.e. all calories are equally fattening.  #1 and #2 are both extreme positions, and as such they get a lot of attention.  But the third group, although less vocal, may be closest to the truth. 

Beyond Ötzi: European Evolutionary History and its Relevance to Diet. Part III

In previous posts, I reviewed some of the evidence suggesting that human evolution has accelerated rapidly since the development of agriculture (and to some degree, before it).  Europeans (and other lineages with a long history of agriculture)  carry known genetic adaptations to the Neolithic diet, and there are probably many adaptations that have not yet been identified.  In my final post in this series, I'll argue that although we've adapted, the adaptation is probably not complete, and we're left in a sort of genetic limbo between the Paleolithic and Neolithic state. 

Recent Genetic Adaptations are Often Crude

It may at first seem strange, but many genes responsible for common genetic disorders show evidence of positive selection.  In other words, the genes that cause these disorders were favored by evolution at some point because they presumably provided a survival advantage.  For example, the sickle cell anemia gene protects against malaria, but if you inherit two copies of it, you end up with a serious and life-threatening disorder (1).  The cystic fibrosis gene may have been selected to protect against one or more infectious diseases, but again if you get two copies of it, quality of life and lifespan are greatly curtailed (2, 3).  Familial Mediterranean fever is a very common disorder in Mediterranean populations, involving painful inflammatory attacks of the digestive tract, and sometimes a deadly condition called amyloidosis.  It shows evidence of positive selection and probably protected against intestinal disease due to the heightened inflammatory state it confers to the digestive tract (4, 5).  Celiac disease, a severe autoimmune reaction to gluten found in some grains, may be a by-product of selection for protection against bacterial infection (6).  Phenylketonuria also shows evidence of positive selection (7), and the list goes on.  It's clear that a lot of our recent evolution was in response to new disease pressures, likely from increased population density, sendentism, and contact with domestic animals.

The Carbohydrate Hypothesis of Obesity: a Critical Examination

Introduction

I'd like to begin by emphasizing that carbohydrate restriction has helped many people lose body fat and improve their metabolic health.  Although it doesn't work for everyone, there is no doubt that carbohydrate restriction causes fat loss in many, perhaps even most obese people.  For a subset of people, the results can be very impressive.  I consider that to be a fact at this point, but that's not what I'll be discussing here. 

What I want to discuss is a hypothesis.  It's the idea, championed by Gary Taubes, that carbohydrate (particularly refined carbohydrate) is the primary cause of common obesity due to its ability to elevate insulin, thereby causing increased fat storage in fat cells.  To demonstrate that I'm representing this hypothesis accurately, here is a quote from his book Good Calories, Bad Calories: