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Saturday, October 30, 2010

Nutrition Rant: Simple vs Complex Carbs

Upddayt  
  Ok, it's crunch time for me.  Semester's end is in sight which means 1 thing: term papers.  Honestly, I'm kind of freaking out.  Guess I just need to divide everything into manageable tasks.  Wait, that would make too much sense.  I should do what most pop psychology/self-help books say.  I should just visualize getting an 'A'.  Or just have a really positive attitude, or something like be open to the universe conspiring to help me--whatever the crap that means.  Or I could do my favourite: just pray.  Prayer will get me through these tough times. Right. What happened to organize your time, and work hard? Why attach all this other useless crap? 
     True story (sort of, I'm changing the details so preserve anonymity). I had a friend (a believer) who was in a car accident.  He worked very hard during physical therapy to get better.  Followed all his doctors' advice, the whole nine yards.  He healed sooner than expected.  When asked about his recovery he attributed it to all the people who prayed for his recovery.  What the crap?  So, modern medicine and physical therapy, and all the effort you made are just frills and gimmicks?  So, I suppose when people who are prayed for don't get better it means their friends and family didn't pray hard enough? Or maybe they prayed to the wrong god?  Have you ever heard of a religious person blame their slow recovery or eventual death on people not praying enough for them?  Probably not, but they'll attribute all the credit to sweet baby jesus (sbj) if things go the way the want.  Makes me want to tackle people.
     Anyway, the whole point of this entry is to let all my millions of readers (thanks for reading Mom!) know that my entries may not be that frequent while I am entering term paper season.  I'll do my best but can't promise much except for the occasional tirade against flawed logic.  (Colbert: But you acknowledge it is logic!)
     So, for tonight I leave you with this, a rant I wrote about a week ago on my friend's blog (which chronicles his weight loss experience) while I was supposed to be working on one of my term papers....enjoy!  Bye the bye, thanks to my sister for the biochemistry overview and fact checking.  She's a real scientist with her own lab coat, test tubes, bunsen burner, and beaker...so listen up!


Context: there had been a couple of comments from the peanut gallery (readers of my friend's blog) with suggestions that I knew had no scientific support, mainly in regards to carbs.   (I'd be lying if I didn't mention that I was a little jealous about how many comments he got from his peanut gallery....c'mon guys! you're way to quiet for a peanut gallery!)



     Just thought I'd throw my two bits in regarding carbs.  First lets begin with weight loss basics. Far and away the most important thing is that calories out must be less than calories in, regardless of source.  If calories in exceeds calories out, you gain weight. If they are equal, you maintain.  This is not to say that there aren't optimal ratios of macro nutrients (simple carbs, complex carbs, proteins, fats) but the calories in/calories out formula is orders of magnitude more important if weight loss is the primary concern.  In regards to the complex vs simple carbs, ultimately it matters not which you eat (in the context of weight loss); what matters is the caloric content.  Since one gram of carbs, simple or complex, is equal to just over 4 calories of energy, ultimately eating one has the same effect as the other in regards to caloric intake.
     Next we come to complex vs simple carbs in the context of "which is better for you".  They are basically chemically the same thing except the complex carbs are chains of simple carbs (i.e. sugars or monosaccharides, in chemistry language).  The metabolic difference is that complex carbs take longer to enter the blood stream because the body has to break down the complex chains of molecules into individual simple sugar molecules before it can absorb them into the blood stream.  
     The rate at which carbs are broken down and absorbed into the blood stream is called the glycemic index.  When we eat foods high in simple sugars (simple carbs) the rate at which the sugars enter our blood stream is high because there is no need for our body to break the molecule down any more than it is.  When a large amount of sugar is "dumped" into the blood stream all at once, the body responds by increasing insulin production.  Insulin production is linked to energy storage.  The body stores energy in two ways: 1.  it converts the sugar into glycogen, where it is stored in the muscles, or 2. in the fat cells where it is stored as fat.  If your muscles are already saturated with glycogen, then your body will tend to store excess glycogen as fat.  
     So, as you can see, if you consume simple carbs in quantities below the bodies threshold for releasing insulin there is no negative effect. But not everything is so simple, many things depend on context.  For instance, for athletes it is important to eat simple carbs after a workout so glycogen stores are replenished quickly. Furthermore, insulin is a transporter of nutrients to cells, so after a workout, we want higher insulin levels so energy is more effectively transported back into our cells. 
     With all this hysteria about carbs it is important to keep a couple of things in mind.  First, they ultimately are broken down in to the same thing. Second, if we have an active life style, both simple and complex carbs are important parts of our diet to meet our energy requirements. The problem is usually that processed foods are calorie dense, not that that simple carbs themselves are bad.  Once again, the problem is calories in vs calories out.  Not macro-nutrient ratios.
     One more note concerning carb hysteria, and this concerns the naturalistic fallacy.  But first a quick return to elementary chemistry.  Both fructose and glucose are monosaccharides (simple sugars).  "Natural" sugar is called sucrose, and contains one fructose and one glucose molecule.  just because it is "natural" doesn't endow it with any magical properties. chemistry is chemistry is chemistry.  That said there is a lot of hysteria concerning high fructose corn syrup (HFCS)  HFCS is also composed of both fructose and sucrose.  the only difference is that because the fructose and sucrose molecules are not bound, the ratio of fructose to glucose can be controlled.  It comes in 55/45 blend or 42/58.  There is nothing inherently "bad" about it.  Any "natural" food is going to have both fructose and sucrose.  In the case of HFCS the fructose content is high or low depending on the level of sweetness required.  Many people (not chemists) claim there is a link between HFCS consumption and obesity.  While it is true that there is correlation, there is not causation.  What causes the obesity is over consumption of calories--not the chemical properties of the molecule. 
Anyway, i should stop ranting....

8 comments:

  1. I was listening to NPR Science Friday podcast 10/07/09 (I'm a little behind), in which David Kessler, former FDA commissioner, makes some interesting claims about the effects of sugar, fat and salt on our brain chemistry. Here's a link to an article, in case you don't have the podcast on file: http://www.washingtonpost.com/wp-dyn/content/article/2009/04/26/AR2009042602711.html. He's all over the web, regardless. It's another piece to add to the weight-control puzzle, and I find it quite intriguing.

    In addition, a study hit the media this week that claims that even one sugary drink a day results in a 15% increase in the chance an individual will develop type 2 diabetes.

    I put this stuff here to distract you from your work, of course. No other reason.

    Your explanation of the difference between simple and complex carbs is the simplest and best I have ever read, so thank you for that. (Or should I thank Chana?)

    Beyond all the stuff we know about human nutrition, I believe (I do!) there is a whole lot of stuff we don't know. Hey, when I was growing up, margarine was "prescribed" for people with high blood serum cholesterol; now we know that transfats are disastrous in their effects. There are many more examples of reversals of opinion on nutritional factors. Vitamin E is good...oops, not so good...etc. Low fat is good...oops, not so good. Low carbs is good...oops, not so good...oops, good again.

    It may be fallacious logic, but I still think that eating closely to the diet we were evolved to eat is probably the safest and healthiest way to go. Simple carbs were rare in our ancestor's diet.

    Anyhow, I think I'm off topic. I hope you are sufficiently distracted now, to go off on another rant.


    Your faithful peanut.

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  4. Oy. When I posted the above comment, I got the message that it was too long, so I split the thing in two and reposted, only to find the original had actually appeared. So the two comments shown as "removed by author" were redundant. In case anyone's wondering.

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  5. great article...and as for the chemistry i should also give credit to my usual cohort: wikipedia!

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  6. @anne. also your point about the experts flip-flopping on what's good or bad for us is well taken with a few caveats. First, as u well know, science is generally self-correcting and the fact that corrections occur is usually an indication of this. as new data comes in and better experiments are conducted, better information is available. also, the claims that are subject to flipflop are usually on the periphery of our knowledge. over time more is learned, consensus is achieved, and the matter is no longer on the periphery. blah blah blah. the bottom line is, if you want health for yourself our your loved ones, you need to pray to sbj, if someone gets sick, it's because you didn't pray enough. it's all your fault!

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  7. Ami baby,

    I want you to ponder some of my questions re: carbs. Then you should probably re-write this post. You know the saying, "A little bit of knowledge is a dangerous thing?" It applies here my friend.

    There are several important physiological factors to consider regarding carbohydrate consumption. Here, you're too quick to make conclusions based on simple mathematical or chemistry-based reasoning. Sometimes there's more to it than a simple 2+2 calculation.

    1. Where is fructose metabolized in the body and where is it stored?

    2. Which metabolic processes are fueled by fructose? Is fructose really just another carb? What daily amount is too much fructose?

    3. Where is glycogen stored in the body and how much can the body hold?

    4. You very lightly touch on the endocrinological effects of consuming high-glycemic index carbs ("simple carbs") versus low-glycemic index carbs ("complex carbs"). What are the effects on other hormones such as glucagon, growth hormone, and IGF-1 when high-GI carbs are consumed?

    5. Do high GI and low GI foods contain the same micronutrient profiles? Do micronutrients play a role in things like energy production, fat metabolization, etc.?

    5. What is the difference between glycemic index and glycemic load? How much carbohydrate volume is required to elicit a measurable insulin response?

    6. You write, "For athletes it is important to eat simple carbs after a workout so glycogen stores are replenished quickly." Does it matter what type of athletic activity or workout this individual is performing? Do all workouts cause the same level of glycogen depletion? What would happen if someone didn't consume simple carbs after a 45-minute weight-training session (using multiple sets of heavy loads in the 4-8 rep range with 3-min rest intervals)?

    7. Do you know anything about somatotypes or metabolic-types? It'd be good to touch on something about that here for your captivated audience.

    Love your blog!
    xoxo
    RD

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  8. @RD. Now THAT's how the peanut gallery makes a comment! Nice! I like the challenge. I don't have time this weekend to answer all the points but I will suggest that you reread my entry and look for how I've qualified what I have said. Several of your questions are already answered. Hint: the main qualification is that what I am saying should be viewed in the context of the average person seeking weight loss. The "athlete" example was to demonstrate that other contexts might require other eating habits. You do however ask some questions I did not answer and if you give me a bit of time to do some research, I'd be interested to know the answers myself. Once again, thank you for you input.
    ap

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