Friday, July 24, 2015

This is what I think of carbs

My Big Fat Carbohydrate Post

(I wrote this first two years ago, then I scrapped it all and started over a year ago and now I think I can finally publish. This morphed into a big block in blogging so maybe I'll actually start blogging again)

To understand whether to eat no / few / "moderate" / high / all the carbs we should first try to understand the physiological and metabolic role of carbohydrates in humans.

Blood sugar - the bad

You already know that your body has tight control over your blood sugar unless you have diabetes, pre-diabetes, or lost your pancreas some way. And if your body doesn't do it for you, then you have to do it with drugs, e.g. insulin. Now, without any control at all there's the risk of coma and death but even with enough control to avoid that there is still damage happening to the body. Glucose, the molecule commonly know as blood sugar, is reactive and forms covalent, reversible adducts to proteins and other biomolecules in your body. This means that they become one molecule but they can spontaneously break apart again. So while the glucose adducts impairs proteins this is only temporary and function is restored. But the adducts can react with oxygen which cleaves the glucose and now the protein is permanently impaired. 
Carbohydrate reactions with proteins is completely reversible until the point where O2 (molecular oxygen) comes into the picture. After that the protein is doomed and the glycation even progresses to another reactive, damaging product. Credit R&D Systems.
Furthermore, the cleavage product on the surface of the protein is also reactive and can react more with the same protein or, even worse, react with another protein, chemically linking them together and eventually forming harmful aggregates. 
This is one of the reasons why diabetics are at much higher risk of blindness and amputation. The peripheral nerves become compromised over time by swings in blood sugar.

tl;dr Blood sugar must be tightly controlled to minimize damage from glycation.

Why do we even want carbohydrates then?

If glucose is so bad then why is it such an intricate part of life? Well, it is quite benign until oxygen cleaves it. All sorts of micro-organisms live in environments without any oxygen and they have no worries about sugars. 
As you may or may not remember from biology class your genes are encoded on DNA and that's the same for all life on Earth (except some viruses that store their genetic information in RNA but that's almost the same). And you might also know that DNA is a polymer with sugar-phosphate backbone. If you don't remember, that's okay, you just need to know that DNA is alternating sugar (ribose) and phosphate. The bases are bound to the sugar - there are four different bases and their order encodes information the same way the 26 letters of the alphabet encodes information when strung after each other in a certain way. Genetic information could have been (and probably was) encoded in a variety of molecules at the dawn of life but the sugar-phosphate with four bases won out in the end. In addition, bacteria found it useful to decorate the outside of their cells with carbohydrates, a glycocalyx, for a multitude of complicated reasons. We, eukaryotes, also decorate our cells with a glycocalyx.
Carbohydrates are very versatile molecules and they are easy to synthesize from just carbon dioxide, water, and energy. And in an environment without oxygen they are stable and compatible with the other molecules of life. But after 1.4 billion years of life on Earth something changed. Oxygen from photosynthesis had finally oxidised everything readily oxidised by oxygen (such as iron turning to rust when it reacts with air) and started to build up in the atmosphere. If there were any bacteria living on land they were probably wiped out before they could adapt - the oceans had oxygen-free areas just as today. And bacteria adapted and some of them (well, archaea) were able to evolve into eukaryotes because of the availability of oxygen (and all animals, plants, fungi, etc are descendants of those eukaryotes). Multicellular life, as we know it, did not emerge until after about 3 billion years of life on Earth when the oxygen content finally rose above 5% (about 800 million years ago).
It doesn't make evolutionary sense to give up on carbohydrates - they are as mentioned a great product to make via photosynthesis from CO2 + H2O and for those of us that aren't photosynthetic it is a readily available source of energy and metabolic building blocks. It would be too far an evolutionary leap to give up on carbohydrates. So instead of evolving away from the use of them life has evolved to control how much free carbohydrate and free oxygen is around. A bit further down I'll get into how integral a part of human biology carbohydrates are.

tl;dr Life evolved in an oxygen-free atmosphere and carbohydrates are easy to make from CO2 and H2O as long as you have some energy.

But sugar is toxic! Fructose is the devil!

What we normally call sugar is sucrose, a single molecule consisting of one glucose and one fructose covalently linked. Now, sucrose is exceptionally easily cleaved to glucose and fructose by our bodies and no studies have yet found a metabolic difference between sucrose and fructose corn sirup (HFCS is 45% fructose and 55% glucose). But HFCS is sweeter and tastier and has very different crystallization properties so you can use it in some foods where sucrose doesn't work well. And because of corn subsidies it is absurdly cheap in the US. Fructose is more reactive than glucose - so is galactose (lactose is similar to sucrose but is made from one glucose and one galactose). If they weren't then we would probably have evolved with one of those molecules as our blood sugar instead. As it is, fructose and galactose are taken up in the small intestine and both removed from the blood stream as soon as they reach the liver. Galactose is converted to glucose through a multi-step pathway but fructose is cleaved in a pathway analogous to glycolysis. Glycolysis produces DHAP and glyceraldehyde-3-phosphate whereas the catabolism of fructose produces DHAP and glyceraldehyde. Glyceraldehyde can be phosphorylated to glyceraldehyde-3-phosphate or made into glycerol. These metabolite fed into a later step in glycolysis so functionally fructose, glucose, and galactose pretty much have the same thing going on in the liver. The big, massive difference is that fructose and galactose must be metabolised in the liver. And if your blood sugar is high then the liver isn't going to turn them into glucose and export them. And if your glycogen stores in the liver are full then these glucose can't be saved for when blood sugar goes down again. So the only option for the liver is to use the raw material and energy from the fructose and galactose and produce fat and attempt to export that fat and move it via the circulation to your fat cells. This is analogous to when the liver degrades excessive amounts of alcohol and has nowhere to dump the energy produced in the process (except that your liver can't produce glucose from alcohol). Which is why I think that excessive fructose/galactose consumption combined with large glucose consumption is the cause of non-alcoholic fatty liver disease (whether glucose from starch, sugar, HFCS, or other sources).
So basically, I think there's a threshold value underneath which fructose and galactose are completely harmless.

tl;dr A high-carbohydrate diet with lots of fructose and lactose is problematic, but in a diet with moderate carbohydrate content you will probably not have a problem with moderate fructose / sucrose / lactose (unless you have fructose malabsorption or you are lactose-intolerant or allergic to dairy of course).

Energy storage (and the low-carb flu blues).

Storage of energy is pretty important; it is basically what our civilization is built upon. First by the storage of food calories in dried and smoked meats and later in grain seeds stored for 1+ years and even later the combustion energy stored in fossil fuels. One of the big challenges in moving forward into a renewable energy society is how we should store energy for when the sun doesn't shine and the wind doesn't blow. And energy for airplanes and rockets etc.
In animals, plants, and fungi energy is stored as glucose polymers and fat. In animals the carbohydrate polymers are called glycogen and in plants we call them starch. The glycogen is more branched than starch so it can be faster broken down or have more glucose added. There are multiple kinds of starch and some are quite branched and digested almost as fast as the glucose monomer and others are quite linear and more slowly digested.
Glycogen binds a lot of water so while the calorie per mass ratio between carbohydrate and fat is ~1:2, the calorie per mass ratio between hydrated glycogen and stored fat is between 1:8 and 1:10. So a quick thought experiment: a mid-thirties man of 78 kg with a body fat of approximately 10% has all the calories stored in his fat magically transformed into glycogen. 0.1 * 78 is 7.8 so he has 7.8 kg fat and glycogen representing the same calories would weigh between 62.4 and 78 kg. So his bodyweight would be in the 132.6 to 210.6 kg range. This is not practical. He would get eaten by a sabre-tooth tiger almost immediately. Therefore glycogen storage is limited and there aren't any specialised cells to store glycogen like there is for fat. Glycogen is mainly stored in the liver and muscle cells. Example guy from before would maximally be able to store 450-650 g of glycogen in his body (about 60 g fat energy equivalent).
That was a bit of a long introduction. But now you know that there's a good reason for storage of carbohydrates to be limited and, from before, you know that there's a good reason for tight control of the concentration of carbohydrates in the bloodstream. So when you habitually eat massive amounts of carbohydrates your body needs to prioritise glucose metabolism over fat metabolism. Every fatty acid metabolised for energy is a bunch of glucose molecules either sitting around in your bloodstream or having to be turned into fatty acids (possibly in the liver or other sensitive tissue). So the rational thing to do is to shut down all fat metabolising enzymes and pathways so there's no resource waste on maintaining them and no energy produced from them.
If you go from a very high carbohydrate consumption to a quite low one, you will feel like you have no energy. And obviously, if you rub your belly a bit, it is clear that you are carrying around plenty of energy. People call this "the low-carb flu" and it takes about 3 to 7 days to clear. It doesn't happen for everyone and it doesn't have the same impact for everyone either. Personally, I think the reason it takes so long must be that transcriptional on-off switches have to be changed (bromo-domain proteins have to change the modification patterns of histones) but I've never seen any research that compares mRNA patterns in humans to macro-nutrient intake. If it were as simple as activating a transcription factor that works directly on DNA then it shouldn't take more than a couple of hours to upregulate the energy-from-fat pathways.

tl;dr High carbohydrate diets prevent you from burning body fat and also make you dependent on constant supplies of carbohydrates through the day to keep energy up.

Glucose as a precursor for important metabolites

Glucose can be metabolised without oxygen to produce a little bit of energy and pyruvate. Anaerobic exercise is an example of when this happens, but your red blood cells also produce energy in this manner (because they lack mitochondria) and some cells in your bone marrow (because that's a low-oxygen environment). Obviously the vast majority of your energy during anaerobic exercise comes from oxygen while none of the energy in red blood cells does. Pyruvate is converted into lactic acid and exported from those cells to be used by other cells or excreted through your skin.
Before the pyruvate step is reached there's 3-phosphoglycerate which can be used to create serine. Serine is reversibly converted to glycine and together these two amino acids are the precursors for the production of a ton of important biomolecules. Think non-essential amino acids, cell membranes, and DNA bases. There is currently research on inhibiting these pathways to limit the reproductive capabilities of cancer cells. Please don't think that this means that a low carb diet means that you'll never get cancer or that someone with a high daily intake of carbohydrates will get cancer.
So, brilliantly, the cells in our bone marrow only have little oxygen available and they also proliferate rapidly, producing lymphocytes and red blood cells. So the increased amounts of glycolysis for energy fits perfectly with higher requirements of raw materials to build new cells.
Basically, carbs are important. But most people don't actually need that much.

tl;dr Glucose is a precursor to molecules important for creating new cells.

Well how much carbohydrate is moderate then?

It depends.
How many new cells are you making? This is dependent on your age (children heal faster than adults and grow in general), your gender (pre-menopausal women produce more new cells than men), and whether you are pregnant.
Apart from that your carbohydrate needs also depends on your activity levels (exercise in the high intensity region consumes some glucose molecules for energy), lean mass (size of muscles and organs) and just plain genetics.
Remember how the storage of carbohydrates is also limited? Carbohydrate requirements are in absolute amounts and not "this fraction of your calorie intake should come from carbohydrates". So if you are really fat you would have a high calorie intake (the slow metabolism idea is a myth, by the way) compared to a skinny person but if age, gender, lean mass etc are comparable then carbohydrate intake should be approximately the same number of grams. So the fat person should have a much lower fraction of their calories from carbohydrates than the skinny bitch.

tl;dr Appropriate carbohydrate intake levels are a function of age, gender, lean mass, activity levels, genetics. Unless you are pregnant.

Please feel free to comment. I am worried that I screwed up the glycogen calculations, so if I am wrong please tell me (and give me some references so I can see how). Please don't get upset if I call your comment stupid. It doesn't mean that I necessarily think that you are stupid. 

Sunday, November 16, 2014

Great article from an Alaskan local paper of all places

The gluten made her do it: How going gluten free saved my daughter's mental health

This is a wonderful read. I love sceptics and this woman is very sceptic. But I have to mention that this was how medicine was practised in the old days. Someone would have heard that something had an effect and then they would try it out. Or they would have an idea like the guy who invented the small-pox vaccine by inoculating a poor kid with cow pox (please do not do anything potentially dangerous to children because you think it will work - talk it over with someone smart like your doctor). Actually, don't do anything potentially dangerous to children or anyone else, full stop.

There's a good point in there that doesn't get much attention: that auto-immune disease tends to run in families. I may have mentioned him on the blog but I have a mate with diabetes 1 and each of his three brothers and both parents have their own auto-immune disease. Different diseases for each one, mind.

I think I got this link from The Paleo Drummer on Facebook. Yep, just checked and I did. Like him if you want - he posts good stuff.

Tuesday, July 1, 2014

Probiotics, prebiotics, counterbiotics...

So you are sucking down the probiotic yoghurt, the carefully fermented Kombucha tea, and your prebiotic supplements? Why?

Okay, fair enough, you want your digestion to work better and you hope that improving your gut flora composition will improve this. But if you also eat a bunch of counterbiotic crap then you are basically just wasting your energy.

Today's rant sparked by Mark's Daily Apple: 16 Things That Affect Your Gut Bacteria and a bunch of other articles on the same subject. And a key note I saw in a gut microbe conference a couple of months ago (I only caught that one talk - it's a bit outside my field).

The thing that boils my piss is that everyone is missing the one factor that probably has the greatest influence on the composition of the gut microbiome (the bacteria that live in your gut and do all sorts of fabulous things for you). Food preservatives.

Food preservatives are specifically designed to kill bacteria or inhibit their growth. Not only that, they are selected to be most effective against the stuff that lives in humans naturally. So we shift the flora of the gut to these other bacteria that tolerate (and metabolise) sulphur compounds and probably some drug resistant bugs as well. It is not a good thing.

Food should be preserved by refrigerating, freezing, drying, pasteurising, or low pH. Or - call me crazy - eaten fresh.
Refrigeration is usually most helpful with things that have innate defences against spoiling. Apples can keep for a year or longer if very carefully stored (traditionally though you only keep them from fall till the end of winter). But it is brilliant.
Freezing is obvious. Not many bacteria are reproducing at minus 18. They can survive it though.
Drying is the same. When the water concentration goes below 20-25% bacteria and fungi are no longer able to grow. Honey is a great example of using low water content to prevent microbial growth in something that should be a feast for any bacteria or fungi. Things that look dry can still contain a lot of water though and condensation is usually enough to spur growth. Drying is the oldest method of food preservation known to man.
Pasteurisation is the process of heating and cooling food very rapidly so it doesn't cook but all micro-organisms are killed. The food is canned or sealed in some kind of pack (like a milk carton) to prevent micro-organisms from re-colonising the food. Although, if you cook things during pasteurisation it is more effective. It doesn't make for tasty milk or juice though.
Making something acidic is classic way of warding off bacterial contamination. This is usually achieved by fermentation, like in yoghurt. So there are actually micro-organisms in the food but they create a hostile environment for pathogenic and foul tasting bacteria. And the bacteria in a fermented food product produces many of the compounds that we otherwise depend on the bacteria in our gut to produce. Good stuff.

Now apart from possible competition from fermentation bacteria all of these preservation methods have no influence on the health of your gut microbiota. And the fermented foods actually (should) help your gut flora. Though the equilibrium of the species diversity in the fermentation wouldn't be identical to the equilibrium of the species in your intestines, it would still be in the same ballpark.

But artificial preservatives are still active when they hit your intestines. You've got benzoate, propionate, sulfur dioxide, sulfites, and EDTA as some of the major compounds. If you go to the Wikipedia page for preservatives EDTA is listed as an antioxidant but the fact of the matter is that it is an effective bacteriostatic and unlike other common metal ion chelators, like citrate, it is also not biodegradable. If you are worried about the ability of phytate to remove essential trace elements from your diet then you extension you should be terrified of EDTA. And just to freak you out even more - parabens in skin care products are absorbed by your skin and enters your blood stream which means they can enter your gut. So in addition to being endocrine disruptors they could also be gut flora disruptors. Just throwing that in there.

I like to think of these compounds as counterbiotics. They aren't antibiotics because they aren't effective enough to kill everything. They just shift the balance from a healthy, normal gut microbiome to something awful. Stay away from them.

"Ah, but surely that's pretty easy," I hear my over-used literary device, which I still don't know the proper word for, say. Well, it could be but in a lot of countries you don't have to advertise preservatives in things like fruit and vegetables. So dried fruit often has a butt-load of preservatives in them unless the packaging specifically says "No artificial preservatives". I have a soft spot for Crazy Jack's soft figs despite the pain in my cheap bastard heart for forking over that much for dried, rehydrated figs.
And if you treat food stuffs with chemicals to resist micro-organisms then you don't have to put it on any ingredient list. Since "a treatment" is analogous to milling or cooking or whatever. This includes things like ground meat (since you can mix that with Finely Textured Beef and pink slime is treated with antibacterial solutions) and flour. But flour is awful anyway. The world is just awful.

tl;dr Don't eat anything processed that you didn't process. Even if the ingredients ought to be paleo you basically can't trust anything processed that comes out of a supermarket. Because lawmakers hate you, that's why.

Thursday, January 2, 2014

New Year's Eve menu

I was tasked with cooking dinner for New Year's Eve this year. Suited me well because I really enjoy cooking but it was a bit tricky since I was still back home so I was cooking half in my mum's kitchen, half in my mate's. It turned out well though - in my opinion anyway.

Just a simple plating of yum. I managed to forget that I had a bunch of avocados in the fridge so we didn't have them :(

  • Baby Romaine lettuce
  • Smoked salmon
  • Crayfish
  • Zingy Ginger Dressing from Well Fed 2
  • Bread. Oh no! The humanity. It was delicious.
  • Probably something more that I've forgotten
I was browsing through the supermarket catalogs to try and get some inspiration from some kind of offer and noticed that a place had Black Iberian Pig shoulder roast. It was pretty expensive but not bad considering that it is the finest pork you can get. And it was really hard to find anything free range otherwise (unless you went organic). So I based a menu on that and of course they didn't have any when I got to the shop. So I ended up with some pretty standard pork. At least it made for a very inexpensive meal and I do like that.

  • Slow-Cooker Italian Pork Roast - no slow cooker so just popped it in a big pot and put in the oven at 110 Celsius, removed the meat juices and drippings and put them in the fridge in the morning and let it roast on.
  • Umami Gravy - this one got some subs. Fish sauce replaced with oyster sauce (not paleo), no dried mushrooms, dried thyme instead of fresh (and possibly a bit too much, I think a teaspoon would have been more than enough), and the broth was definitely not paleo or organic or homemade or anything. To make up for the lack of dried mushrooms I added all of the meat juices (after removing most of the fat) from the roast. Any slow-cooked roast needs some juice returned to it before serving. You can just use the juices directly if you don't want to make gravy but it was awesome.
  • Casablanca Carrots from Well Fed 2. They were bloody amazing. Silly name though.
  • Belly Dance Beet Salad from Well Fed 2 or Also a silly name. Since these are served cold or room temperature I think they could have gained from using an oil with a lower melting point than coconut oil when baking them. And I made them the day before and they suck liquid so I think it would have been good to have given them a splash more orange juice before serving them. They were still rather delicious though. I also waited until serving with adding the pistachios and I think that worked well.
  • Oven roasted sweet potatoes. Oiled and sprinkled with salt and rosemary. Baked with the grill on. You never get a good texture with just convection heating.
  • A green salad. I think it was rocket, radicchio, and something else and then with cucumber and cherry plum tomatoes. 
  • Leftover bread and dressing from the starter. Yes, I am that lazy.
I did the carrots and the beets the day before and the dressing and most of the gravy in the morning (along with dessert). Then I just packed it all up and finished the sauce and made the sweet potatoes and salad at my friends place where we had the party. Pretty easy.

I firmly believe that one of the defining characteristics of dessert is the neural reward elicited from high concentrations of fat and carbohydrate. Therefore I don't think any of the "paleo" desserts you see on Pinterest or wherever are actually paleo. Unless they aren't any good and if they aren't then that's just money out the window. I did however make a cake without flours, preservatives, emulsifiers, thickeners, stabilisers, etc.
  • Chocolate pie with walnut-date crust. I have no clue what a graham cracker tastes like so I'm just going with this name instead. The only good chocolate I could find which seemed to give a damn about slavery was björnsted from Germany. I usually always mock German chocolate so that was a nice surprise. And it's made from only 3 ingredients which I was really pleased with. Nomnompaleo says to use several cans of coconut milk but I found that one can separated gave me almost exactly one cup of coconut cream. I used Jefi brand Tropical Delite coconut milk and it only had two ingredients (coconut and water) and really separated well. Definitely try to find one without any emulsifiers or such. I found this in a Middle Eastern green grocers and I usually have to go to an Asian supermarket in the UK. Oh, and I sprinkled orange zest on top because it's much prettier that way.
  • A single slice of 5-6 different kinds of fruit. I didn't know most of them so I can't actually remember their names. Basically, it lightened a cake that is quite rich.
And of course I drank beer, white wine, red wine, champagne, crémant, prosecco, more beer, and got laid. It's two days later (really late in the evening) and the hangover is just about gone. I don't regret anything but it is remarkable how stupid I still am two days after drinking. Thinking was so hard today.

Sunday, December 1, 2013

A Doctor's View on Obesity

I just read this very honest article by an Australian physician about her experiences with obesity, both as an attending doctor in a hospital and specifically as the doctor that does the pre-surgical evaluation of potential bariatric surgery patients (link shared by Crossfit HQ's Facebook).
Fat City - What can stop obesity?
It's a brilliant read. She covers the dilemma of having to point out that a patient's weight is negatively impacting their health while knowing the kind of shame she is inflicting on them (on average fat shaming is counter-productive and just plain wrong).
To me the most interesting parts is about the bariactric surgery. If I remember correctly gastric banding has a success rate ~50% and a gastric by-pass has a success rate ~75%. Death from complications is about 0.5%. From my friend, who's an anaesthesiologist and has worked on a number of these surgeries, this is pretty bad but the challenge is that any time you put the morbidly obese through any surgery you run a number of risks that are absent from "normal" surgery. So in addition to the high risk of bursting stitches there's also a risk associated with general anaesthesia. But if you decide not to do the surgery then you still get morbidly obese patients under the scalpel at some point.
I usually hate the whole IIFYM mentality (If It Fits Your Macros - a concept that you eat anything as long as the three macro-nutrients hit your target) but for someone like the 200 kg young man she describes, who literally doesn't have anything enjoyable in his life apart from junk food, I think it is actually a better option than Paleo. Phew, too long sentence. But when someone can't even leave their bed some days then asking them to cook all their meals and ignore all junk is probably a bridge too far. Someone like that needs to manage how many calories are going in and he needs to do it in the simplest way possible. If he gets that working then he might learn that he can eat more food if he goes for a healthier option. Let's do some math! I love numbers. He could probably stand to lose 120 kg. There's ~7.2 kcal/g in adipose tissue (that's probably not the most precise number btw). So he has 864,000 kcal to lose. If we guess that his metabolism turns over 3000 kcal per day (yes, the bigger people are, the higher their base metabolism is). That might be low. Let's say 4000 because that's definitely too much. Then he has stored enough energy for more than 216 days. Without any calories from outside of his body. So basically, this dude needs a diet that is sustainable for about 3 years. Not a "Lose 5 pounds in 7 days with this skinny bitch we hate"-Cosmo-cover-diet. I don't like to admit it but Brad Pilon's Eat Stop Eat or Martin Berkhan's methods would probably be the best for him (both are intermittent fasting approaches with calorie restriction). Of course any successful weight-loss diet is simply a set of ways of acting that allows a person to eat fewer calories than their body needs without experiencing hunger (and preferably without a down-regulation of thyroid function).

My only issue with that article is that she thinks you can't be hungry when your stomach is full. It's a terrible feeling but perfectly possible. It's true that the stomach being full sends one signal to decrease the sensation of hunger but if you are in calorie deficit then that's another signal to increase hunger. Protein deficiency increases hunger. High concentration of fats and monosaccharides override satiety. I'm sure there's a lot more. Now I'm hungry.

Saturday, November 9, 2013

BMI categories

Less than 18.5 : Underweight
18.5 to 25     : Scrawny
25 to 30       : Overweight
More than 30   : Obese

Because your weight is wrong and your height is wrong and you'll get sick and be a burden to society.
And no one will ever love you. Least of all you.

Even Wikipedia has a nice section on the problems with BMI.

Wednesday, October 16, 2013

But it's so tasty!

Great! Let's eat everything tasty.
Tasty, tasty ethylene glycol, diethylene glycol and lead sugar (it tastes like sugar but it's lead! Amazing!).

By now you have hopefully figured out that I am being sarcastic. There are plenty of things that aren't good for us that still taste nice. And you already knew that. But instead of spending so much energy on "Oh, it's so naughty but so good. I know I shouldn't." spend some energy on "Oh, this is yummy and good for me. Score! *nom*nom*nom*.". Guilt is the best spice but leave it for your freaky sex games with your consenting partner.