paleo

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Sunday, 21 January 2018

The variability diet

'Tis the time for dieting. Let me jump on the band wagon with a completely new diet that fits to this blog: the variability diet.

Antipodes can skip this post or stay for some interesting science ideas; countries in the Southern Hemisphere apparently do not have a seasonal cycle in dieting.

The National Weight Control Registry is proud they found ten thousand people who managed to keep the weight off for a longer time. Ten thousand people world wide sounds to me more as if most diets hopelessly fail on the long term.

It could naturally be that the obesity epidemic in the West is an epidemic of sloth, a failure to count calories as well as lions do.

Oh, wait.

I would venture: we need fresh ideas.

Most diets are defined by averages. The right amount of calories, the right macro-nutrients (carbs, fats and proteins), in the right number of portions per day. In observational studies, scientists compute the average number of calories eaten and calories burned, they compute the average fractions of every macro-nutrient, maybe even the average amount of vegetables and animal foods eaten, the average number of hours of sleep, the averages of this and the average of that. And even if they do not explicitly average, their analysis methods (for example, multiple regressions) will only notice differences in the average.

The main exception from prescribing the averages of a diet is the advice to eat a diverse diet or to eat many different colours of fruits and vegetables. For example in the USA one recommendation is: "A healthy eating pattern includes: A variety of vegetables from all of the subgroups—dark green, red and orange, legumes (beans and peas), starchy, and other."

To be honest, "a variety of" is a somewhat unsophisticated way to describe variability. First of all it is rather unspecific. Other formulations often ask for more variability, but just like for the average, you can have too much or too little variability and an optimal amount in the middle. But lets be generous and assume the typical variability is way below optimal.

The biggest problem is that for variability you always need to define an averaging (time) scale. The red and the blue symbols in the figure below have the same total variability (a standard deviation of one). However, as the thick line shows, the blue line has much more variability on longer averaging time scales, while the blue values vary less from day to day.

Daily eating a wide variety of vegetables of vegetables from all over the world is nowadays possible and produces a lot of variability on short time scales, like the red symbols. But on long time scales it lacks variability ($). My father complained that in his youth he had to eat beans for weeks on end when the beans in the garden were ready for harvest. That was a diet with not much variability on short time scales, but a lot on longer time scales, like the blue symbols.

There is a diet that mimics this, the seasonal diet. For out of touch city folks like me, there is even a seasonal food calendar; I have one on the inside of a kitchen cabinet. This diet is mostly promoted as a diet that saves you money and it good for the environment. Sometimes it is advised for ensuring the food is healthier and tastier because fresher, but maybe the variability is also helpful.

What is the right time scale? I do not know. One reason to write this post is the hope that a nutritional scientist is inspired to take variability into account. When it comes to carbohydrates (bread, pasta, rice) it may be good to once in a while empty the (glycogen; animal starch) stores and train your body to also use fat for fuel. The liver has about 10 to 12 hours of glycogen in store. I wonder whether this is related to the German advice not to eat after 6pm or the Italians who eat a lot in the evening, but hardly eat any breakfast. These two national recommendations seem to conflict, but have a fasting period of over 12 hours in common.

Intermittent fasting seems to be an effective way to lose weight, at least for people able to do so. There are many varieties. Some people only eat during a few hours a day, every day. Others once in a while do not eat for 24 hours (breakfast to breakfast; skip lunch and diner) or 36 hours (diner to breakfast). I like this method, at least in summer because I get cold after some time when my metabolism goes down. Women often do not like it.

"Ancient humans ate a large variety of foods, which is why we are adapted to so many. Human variation is high though, since our lineage has become so populous and geographically wide-ranging."
Melissa McEwen

Many diets have a honeymoon period of one or two months in which they work like a charm (raw food diet; low carb diet). A blog called 180 Degree Health claims to have success by breaking all the healthy eating rules. Apparently diametrically opposed diets work in the beginning. If you are lucky your diet works for about half a year, but typically the weight and the health problems come back.

From the variability point of view a new diet is initially a change, variability, in the long-term a diet often makes your food more monotonous.

This honeymoon period suggests that another interesting time scale is a month to half a year. This honeymoon period was what provoked my to start thinking about a variability diet. Why stick with a diet for a year, why not try 12 diets for a month and benefit from the honeymoon period 12 times?

The honeymoon period is also why diet studies without a control group are a problem.

Randomized Control Trials, difference in success after 6 months, similar and less success after 12 months.

Variability in sports

What is the right time scale? Maybe all of them!? Nature is characterized by variability on all time (and spatial) scales.

The importance of variability is broadly acknowledged in sports and sports training uses several time scales, from hours to years. Sports training is based on periodization. A simple [[periodization scheme]] for a beginning runner could be: one has microcycles of one week (one hard run a week), mesocycles of about one month (one more relaxed week a month) and macrocycles of a year (preparation, competition and transition (rest) phase). If you add to this a 4-year cycle for Olympic athletes and a career plan for a professional athlete you start to think in variability on all time scales.

In weight training a similar concept is to include a deloading period/week once in a while in which you take it easy, which helps to keep getting stronger in the long run. Weight training fans can talk for hours about how fast exercises should be performed, how many repetitions, how many sets and how often per week one should go to the gym. There we have four more time scales. Five if you make one exercise a week extra hard.

Intermittent fasting could be seem as weight training. A fruitarian diet may be the equivalent of lying in bed all day; if you can handle the sugar load, fruits normally eaten hardly contain any anti-nutrients you body needs to defend itself against. On the other side, a very low carb may for some be the equivalent of running a marathon every day. If you think in terms of exercise, you would set a stressor by eating very low carb for a short period and then recover and become stronger while eating a mixed diet including fruits. No idea whether this specific example works, but I wonder why people do not think in these terms when in comes to nutrition.

Reasons why variability may be healthy

A healthy gut microbiome, that is the ecosystem in your intestines, is important for health and weight loss. A human has more mass (and stores) than a microbe. Missing nutrients thus hurt microbes more than us and fasting gives our immune system the possibility to fight bad germs more easily. This is a reason why we often do not feel like eating when ill. This also suggests that the microbiome may be the most sensitive to variability and the main target of a variability diet.

The biodiversity of the microbiome is linked to being overweight. The causal relationship may go both ways. Transferring the microbiome of a fat mouse to a skinny mouse makes it fatter, but losing weight also changes the microbiome. The obesity epidemic and other metabolic deceases in the West may be related to a reduced intestinal biodiversity in the West. This biodiversity has a seasonal cycle and the diversity increases on a calorie restricted diet, which gives hope this may be reversible.

Microbes are an ecosystem and their composition will as such highly likely be determined by variability (pioneer populations, tidal plain versus salt marsh; cactuses need to be dry regularly to fight root decease; palm trees grow where the minimum temperature is above zero degrees, fire keeps the savanna open, ...).

Variability also makes it easier for the body to learn which food does what to your body, especially when the short-period diets are relatively simple to get more long-term variability. Without paleo blogs, I would never have noticed that I do not handle grains well because I never went without grains for a long enough time to notice the difference.

My experiment

How could such a variability diet look like? Except for mimicking the seasonal diet your grandma ate, I have no idea. But this is the experiment I tried myself. I picked a period of 4 days and relatively large changes in diet. The 4 days nicely fit to my 2 times a week grocery shopping rhythm. These are some of the short-term diets I tried. The diets probably look funny to most because I do not eat grains.

4 Days low protein: Fried potatoes, fruit meals and a large vegetable stew without meat, but with butter.
4 Days low fat: I was at a conference and thought that low fat would be the easiest diet variety. Luckily they had lots of fish. Otherwise, vegetable omelets, meat, greens, yogurt with fruits.
2 Days low carb: Brisket, fried eggs with cream, too much cashews, pork chops with red cabbage.

7 Days deloading: Whatever my body wanted.
I started this 4 day period planning to eat yogurt and fruit. But after four meals, I just could not eat it any more and put in a low carb day. Repeat not to waste the fruits.
6 Days a diet which was intended to be (almost) all animal products, but without dairy, so I used olive oil. That turned out to be too low carb, so I have added one fruit to most of my meals. This period was a bit longer than the others. It felt good and I made a delicious soup from whole 2-kg chicken, which takes some days to finish, if you would like to eat more than just soup.
2 Transition days.
Started with a potato diet, with some vegetables and nut butter for taste. I mainly baked the potatoes in a little butter or olive oil. Plus about 2 fruits a day.
5 Days low carb, mainly animal products, meat, eggs, heavy cream, butter, bacon, and one or two fruits a day. I had planned to do this one week, but my temperature started to drop (cold hands, feet and ears).
3 Days my normal diet.
A low protein week: backed potatoes with butter and cream and fruits.
2 Weeks of meetings and a conference in sugar and flour capital Vienna, These weeks I planned to eat whatever is available. To my surprise you can also get very good food in Vienna, lots of offal and grass-fed beef was available in the restaurants (Universitätsbräuhaus (University brewery, Unibräu) & Servitenwirt) I visited.
1 Week my normal paleo-ish diet to recover from the meeting.
3 Starch days, a lot of rice pudding (rice cooked in hay milk and butter, served with a little sugar and cinnamon or backed apples) and one normal meal.

There are many more things one could try. Also trying longer periods would make sense.

High Acid (vinegar)
Low Acid (My mum used to have chalk for cooking, no idea how she used it.)
No dairy
Salty or salt free
Pig out
Salad, raw vegetables
Drink a lot, or little
A lot of vegetables or just empty carbs.
Avoid nightshades, citrus fruits or [[FODMAPs]]

The good news is that I lost weight and felt good. The bad news is that I was not able to continue the diet. Inventing one or two new diets a week is exhausting. Thinking so much about what to eat is not my thing. So I went on with just occasional intermittent fasting (which requires no planning) and stopped doing that in winter.

It would be great if there were a traditional fasting celebration in spring to remind you to start with intermittent fasting again.

So you could say my n=1 experiment failed, because the main thing of a working diet is being able to stick to it. But maybe that is fixable (is there an app for that?) and people are different.

It is some time ago I tried this. I think I will try again. 'Tis the time of the year.

Tuesday, 22 July 2014

Six sleep and jetlag tips

Blogging has been light lately, I was at a workshop on statistics and homogenization in the USA. For me as old European this is another continent, 8 hours away. Thus I thought I'd share some jetlag tips, most of which are generally good sleeping tips as well. The timing is good: many people have trouble sleeping during the warm summer nights.

As far as I know, science does not really understand why we sleep. My guess would be: variability. Which is always my answer to stuff we do not understand. Most problems involving only the mean have been solved by now.

By doing the repairs and maintenance of your body at night, when there was not much else to do in the times before electrical light, you can allocate more energy to other stuff during the day and, for example, outrun someone who is repairing his cells all the time. Creating some variability in tasks between day and night thus seems to make evolutionary sense.

(The part I do not understand is why you have to lie down and close your eyes. Isn't is enough to simply rest? That seems to be so much less dangerous. But maybe the danger was not that large in bands where everyone has its own sleeping rhythm and someone is wake at most times.)

To differentiate between day and night, you need internal clocks to coordinate the action. Clocks that tell you to increase your cortisol in the hour before waking up, to get your body ready for action again. Clocks that tell you to reduce urine production during the night. Clocks that reduce the motility of your intestines while sleeping. Clocks that tell you to wind down and get ready for sleep in the evening. And so on.

These chemical clocks need to be synchronized, they do so mainly by light, but I have heard claims that also movement is signal for these clocks to keep track of the time. Without synchronization most people have an internal clock that runs one or more hours late and produces days that are longer than 24 hours. This natural period varies considerably. People who are night owls, most scientists for example, have longer internal days as early birds. I seem to be an extreme owl and can stay awake and concentrated all night. The rising sun is sometimes my last reminder that I really need to get to bed because otherwise my time becomes too much off with the rest of society.

1. Take your natural rhythm into account

Which brings me to tip 1. Or maybe experiment 1. For me as an owl, flying East is hard. It makes the day shorter and the days are already much too short for me anyway. In case of this last flight home, it made the day 8 hours shorter, not 24, but only 16 hours. Horror. Thus you have to go to bed well before you are tired and consequently cannot sleep.

My experiment was to stay awake during the flight. That made my day not 8 hours shorter, but 16 hours longer. Such a 40 hour day is probably too much for most, but given my natural long day, this seems to have worked perfectly for me. I hardly had any jetlag this time, almost like flying West, which also comes easy for me. I am curious what the experiences of others are. And can this trick be used by early birds flying West as well?

2. Light exposure

Light is vital for setting your internal clocks. Try and get as much sun as possible after your jetlag. Walk to work, take breaks outside, eat your meals outside, whatever is feasible. Often conferences are in darkened rooms, which mess up you clocks even without jetlag. Consider arriving early and spend your days before the conference outside.

Also on normal days, night owls should make sure that they get as much light exposure as possible and get outdoors early in the day to quickly tell your internal clock that it is day. It may help early birds to stay awake to seek the sun later in the day.

3. Artificial light

Artificial light, especially blue light, fools your internal clocks into thinking it is still day. If you do not become sleepy and have trouble getting to sleep, try to limit your exposure to artificial light in the evening. There are large differences in the color of the light between light bulb, select one that gives a nice warm glow and do not make the room too bright. The availability of artificial light is thought to have increased variability in sleeping times by making it easier for night owls to stay awake.

4. Blue glowing screens

Also monitors and smartphones give of a lot of blue light. I have f.lux installed on all my computers, it removes the blue light component from your monitor. I am not sure it helped me, but it cannot hurt in any way as long as the work you do is not color-sensitive. (If it sometimes it, you can easily turn it off.)

5. Pitch dark

Make sure that your sleeping room is completely dark. This signals your clocks that it is night. Doing so improved the quality of my sleep a lot. They say this becomes more important as you age. Before putting blinders on your windows or hang up light blocking curtains, you can experiment and see if this is important for you by putting on a sleeping mask or simply lay a dark t-shirt over your eyes. (As an aside, also sleeping on a firm surface rather than a mattress improved the quality of my sleep I am curious whether other people have similar experiences.)

6. Sleep rhythm

The ideal nowadays is to sleep in one long period. This may be a quite recent invention to be able to use the evening productively using artificial light. Before people are thought to have slept a period after sunset, woke up for a few hours doing some stuff humans do and sleep another period. Even if this turns out not to be true, there is nothing wrong with sleeping in a few periods or with taking a nap. If you are awake, just get up, do something and try again later. I am writing this post in such a phase. Uncommon for me, probably due to the jetlag, I was tired at 8pm and slept two hours. When this post is finished, I will sleep the other 6 hours.

Related to this: try not to use an alarm clock. I realize this is difficult for most people due to social pressures. In this case you can set your alarm clock at a late time, so that you will often wake up before your alarm clock. Many people report waking up with gradually increasing light intensities is more pleasant, but also these devices are still an alarm clocks.

What do you think? Do you have any experience with this? Any more tips that may be useful?

Monday, 3 June 2013

Reviews Paleofantasy? Maybe eating meat, nuts, fruit and vegetables is okay

Jason Collins has just written a review of Marlene Zuk’s book "Paleofantasy: What Evolution Really Tells Us about Sex, Diet, and How We Live". Having read several reviews of this book, this review sounds like the one I would have written, had I read the book. (I am not the only one; many reviews were written based upon previous articles by Zuk and not based on her book. Jason Collins did read the book.)

... Zuk parades a series of straw men rather than searching for the more sophisticated arguments of Paleo advocates. Many chapters begin with misspelled comments that Zuk found under blog posts. While Zuk shoots the fish in the barrel, the more interesting targets are not addressed.

I had almost chosen as title: debunking a book that promotes a diet full of processed "foods", grains and sugar and warns for a diet of meat, nuts, fruit and vegetables. Fortunately, that super straw man title was too long. This one, Maybe eating meat, nuts, fruit and vegetables is okay, is straw manly enough; it can be hard find a good concise title.

My paleofantasy

To me, paleo is not much more than a productive generator of hypothesis and a good story that helps to bundle several suggests for life-style changes.

Although you can say, that it would be very surprising that a diet humans were eating for a such long time, a time largely without chronic decease, would be unhealthy in this modern age. Not impossible, but you would expect very strong proof, much stronger as, for example, the epidemiological study promoted by T. Colin Campbell in his vegan bible: The China Study.

And the narrative is good enough to encourage people to try a range of different diets and life-style options to see on which one they feel best and not stick to the officially healthy one, if it is not working for them. Just play and experiment, that is what defines us as humans.

Review by Hunt Gather Love

You can go to Hunt Gather Love, for a more technical and intelligent review on Paleofantasy from someone who "wanted to like this book". Another good related post from the same blog: paleo fantasies: Debunking The Carnivore Ape Narrative, makes clear that paleo hypothesis does not prescribe a diet of only meat, nor a low-carb diet.

Friday, 1 February 2013

The social dimension of health

Maybe I could even have title this post: the social dimension of life.

Many people seem to interpret "survival of the fittest" as relating to the fitness studio. While the fittest are simply those who survived. Whether you survive depends on lot on your tribe and only partially on your self, if you do not behave too stupidly.

Frank Forencich speaking at the Ancestral Health Symposium, 2012, explains this social part of health and a full life.

Frank Forencich is blogging at The Exuberant Animal and is a refreshing sound in the paleo world. His posts are thought provoking and well worth reading.

Traditional milk in Germany: raw and hay milk

Photo used with permission from heumlich.at.

In the ancestral health community raw milk and milk from grass-fed cows is highly praised. See Chris Kresser for an excellent overview of the benefits and the small risks of raw milk. Mark Sisson gives a nice overview of the more healthy fat composition of pastured butter. It took me some time to understand the situation in Germany, until I knew the two magic words: Vorzugsmilch and Heumilch.

Vorzugsmilch

Raw milk is not pasteurised and not homogenized. Pasteurisation is quickly heating and cooling to reduce the bacteria concentration. Milk is white because of all the small fat droplets in the water. In homogenization, milk is pressed through a valve at very high pressures to make the droplets smaller, which prolongs the time until the droplets combine to form cream at the top of the milk.

In Germany, retail of normal raw milk is forbidden, but a farmer is allowed to sell his raw milk directly to consumers. Raw milk sold in shops is called Vorzugsmilch, let's call it merit milk in English, I like alliteration. Cows and farms producing merit milk are inspected regularly and the milk has to get to the consumer within 96 hours. According to Andrea Fink-Keßler (agricultural scientist) the diet of the cows producing Vorzugsmilch is similar as for hay milk; see below.

The paleo culture

A volunteer of the Ancestral Health Symposium 2012 has criticized the culture of the paleo movement. Richard Nikoley apparently felt attacked and as a prolific blogger immediately wrote a hot tempered post in defence. (In the meantime, the blog with the criticism has been deleted due to the personal attacks and threats.) Richards defensive post focused on the few lines that went over the top.

The demographic at this event was almost all white, child bearing age, healthy, wealthy, highly educated, libertarian, racist, sexist and bigoted.

I presume these lines were more provoked by a life of discrimination as by a single symposium.

It is normal to be defensive while receiving criticism. The day after, one often notices that honest feedback is actually very valuable, that it gives rare and precious insight into how one is seen from the outside. The valuable points of the criticism were (i) that she did not feel welcome, as a not wealthy person and also as an older woman. Furthermore, there were (ii) many crackpots at the symposium.

Demographics

I must admit that I also sometimes find the paleo culture to be rather off putting. The reason I stay is because many good ideas from the paleo community have helped improve my health enormously. The main bloggers are friendly and many focus just on science, which is neutral, but you are often just one click away from the National Rife Association. The community has a strong focus on the health effects of nature, but I never saw a link to a nature conservation group. Paleo is inspired by the life style of hunter-gatherers, but I had to hear about Survival International, an organisation that helps indigenous peoples protect themselves, on the German radio. There is lots of talk about expensive food, supplements and gear, but not about anti-hierarchical strategies used by hunter-gather groups to keep their band egalitarian and strong. Much of the advice is focused on males and it may, for example, well be that the standard routines for intermittent fasting are too heavy for woman.

Paleo and fruitarian lifestyles have a lot in common

My new fitness trainer eats a lot of fruit. And she looks darn healthy. Now I know, you should not take weight-training advice from a professional body builder or risk serious overtraining, but still I was intrigued and did some research. The vegan and paleo communities are often not on friendly terms. Thus what struck me most researching fruitarian blogs, was how similar many of the ideas were.

A very strict fruitarian only eats fruits in the common meaning, sweet and juicy fruits from trees or bushes. Others also include vegetable fruits such as avocados, tomatoes and cucumbers, still others also include nuts, many regularly eat salad. To get sufficient calories from fruits, a fruitarian has to eat several kilograms of fruit. Some people calling themselves fruitarians actually get most calories from nuts and avocados. In this post fruitarians are people getting most calories from simple carbohydrates, that is from sweet fruits.

The paleolithic lifestyle is inspired by the way people lived before agriculture. As the information from the Paleolithic Age is scarce, in praxis this often means, that existing hunter gatherers and their diets and lifestyles are studied. Such bands often trade with nearby agriculturalists and thus no longer live a true stone-age life. Still as long as they are free from the deceases of civilisation, they provide good role models in my view. Similarly, many paleos also look at other existing cultures that are in good health. In this respect the paleo community is close to the Weston A Price Foundation, who seek guidance with how people lived a few generations ago. The paleo diet is best defined by what it not eaten: processed foods, grains, sugar and refined seed oils.

Natural cures for Asthma?

About two years ago, I was diagnosed with asthma. After some changes to my lifestyle, the last whole body plethysmography measurement showed that my lungs are fine again although I do not use any medication anymore. The asthma is gone!

I would like to share these changes with you, hoping they may also benefit you and also to hear back what benefited others and what not. My personal experiment is a little small (n=1), thus it may well be that some improvement were just by accident and not because of lifestyle change. I have to say that I only had very light asthma. I never had an asthmatic attack, but regularly did wheeze lightly when exhaling at night, my voice was not so strong anymore and my lungs produced too much mucus (leading to some coughing and a coated tongue). Another sign was that the reliever medication (Bronchodilators) made jogging a lot easier.

Asthma is on the rise the last 50 years in the West. Already this points to lifestyle factors being important. Not much seems to be known about which factors these are. It has been noted that children growing up at farms as less affected by asthma as urban children. Based on this, it has been theorized that childhood contact with microbes is beneficial, but I guess there are quite a few other differences between the life on the country side and in cities.

The main changes I made are that I started with intermittent fasting, and nowadays sleep on a firm surface, and do much more walking/hiking. Also important may have been that I do not any grains any more, do less jogging and more sprinting and that I regularly tanning for more vitamin D.

Freedom to learn

On Psychology Today Peter Gray writes an intriguing blog on education called Freedom to learn.. In it he argues that forcing children to learn stifles their innate motivation to teach themselves and is thus counter productive.

The post titled Seven Sins of forced education gives as the fourth sin: "Interference with the development of personal responsibility and self-direction."

Children are biologically predisposed to take responsibility for their own education... The implicit and sometimes explicit message of our forced schooling system is: "If you do what you are told to do in school, everything will work out well for you." Children who buy into that may stop taking responsibility for their own education.

When I look back on my time as a student, what wonders me most, is that I never had the idea to explore a certain topic myself. I just read the books the school or university told me to read and that was it. Only as a researcher I started to take responsibility for my own eduction.

Another sin that fits well to the theme of the blog, variability, is the "Reduction in diversity of skills, knowledge, and ways of thinking." In a highly diversified economy, it is detrimental to teach everyone the same topics.

A highly recommended blog, Freedom to learn.

Sunday, 12 June 2011

Sleep and diversity

In an interesting article on sleep in traditional societies on Science News (which is not the news section of Science), Bruce Bower states that people used to sleep in groups and that differences in sleeping time where an advantage as it provided better protection for the sleeping group.

... sleep typically unfolds in shared spaces that feature constant background noise emanating from other sleepers, various domestic animals, fires maintained for warmth and protection from predators, and other people's nearby nighttime activities.

In traditional settings, however, highly variable sleep schedules among individuals and age groups prove invaluable, since they allow for someone to be awake or easily roused at all times should danger arise, Worthman holds.

Thus a diversity of sleep schedules may be well adaptive, may have been selected for by evolution as it provides better protection. It would be great if modern society would allow people to follow these natural needs, instead of forcing a fixed schedule on early birds and night owls.

By the way, the circadian sleep-wake cycle itself is an example of variability in the activity level. Science still wonders why we sleep. It may well be related to this variability, which allows one to be more active during the day; while at night the reserves are filled again and repairs are performed. A remaining question would still be why you need to close your eyes for this, which is dangerous.

Sleeping without mattress

I found the article linked on the page The Ergonomics of Sleep: Why a Hard Surface can Provide Sweet Dreams. This page argues that sleeping on a mattress is a recent invention and may not be ideal for everyone. To me it makes sense to use traditional behavior as Null-hypothesis; modern ideas are often useful (for instance, hygiene and vaccinations), but should be tested. Thus one week ago, I removed my mattress to see it this works for me and slept on the wooden panel below, but I did add an exercise mat and a comforter (German: Bettdecke) as cushioning. It is definitely not comfortable, but I sleep well, wake up much more alert and it is easy to get out of bed.

What makes it uncomfortable is that your weight is mainly born by your bones. If you sleep on your back your weight is on your heels, pelvis, shoulder blades and skull, on your side it is on your ankle, pelvis and shoulder, on your front the tops of the feet, the knees, pelvis, ribs (man) and collar bones. May there be a reason why exactly these places have no padding, no fat nor muscle? The reduced pressure on the weak body parts could maybe be beneficial for the circulation. Lying in a dimple on a mattress could change your posture (round back) and consequently your breathing.

I am curious what other people experienced and know about this topic; please leave a comment.

Saturday, 28 May 2011

Is obesity bias evolutionary?

On the Huffington Post and on his own blog, David Katz, MD, asks the important question why so many people are obese nowadays. His answer does not sound convincing, he argues that there a bias toward obesity is an evolutionary advantage.

This might have been possible, but a simple calculation shows that this is unlikely. A man who is 100 kg too heavy and 50 years old, to a first approximation ate 2 kg per year too much. Two kilograms of fat is 1400 Cal and thus comparable to what one eats in 4 days to one week, depending on your, height, weight and level of activity. In other words, this man ate only about one or two percent more than he should have. You may increase this number somewhat to account for the fact that a larger body also needs more energy. Still the additional amount eaten by an overweight person is small and will be hardly noticeable in day life.

In the times that humans were hunters and gatherers, it should have been easily possible to eat a few percent more than usual. The year to year variability in the availability of resources is large; on the negative side think for instance of floods, droughts and grasshopper plagues. A human that is able to survive in a bad year, should easily be able to hunt or gather double his need in good years. One would expect the maximum amount of food a person can find is much more than a few percent more than the average needed. Otherwise, a human with a bit of bad luck would soon starve to death and be removed from the gene pool.

Pages

Sunday, 21 January 2018

Variability in sports

Reasons why variability may be healthy

My experiment

Related reading

Tuesday, 22 July 2014

1. Take your natural rhythm into account

2. Light exposure

3. Artificial light

4. Blue glowing screens

5. Pitch dark

6. Sleep rhythm

Monday, 3 June 2013

My paleofantasy

Review by Hunt Gather Love

Friday, 1 February 2013

Friday, 23 November 2012

Vorzugsmilch

Friday, 17 August 2012

Demographics

Saturday, 19 May 2012

Friday, 16 December 2011

Monday, 14 November 2011

Further reading

Sunday, 12 June 2011

Sleeping without mattress

Further reading

Saturday, 28 May 2011

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