How well do you handle carbohydrates? Time to find out

As discussed in my last post, each of us is able to handle and metabolize carbohydrate sources differently.  In my early days of paleo, I was an anti-carb hardliner.  Even though I felt strongly about low carb because I had seen great results in my own life, I failed to realize that diet is not a “one size fits all” game.  I remember trying to explain to Dr. Kim, a 70-something-year-old Korean doctor that I worked with, why eating white rice is bad.  I’ll never forget his simple rhetorical question, “If white rice so bad, how come my mother live to 99?”

It took me some time to come around, but after reading Wired to Eat and performing my own tests, I’ve softened my stance a bit.  It is clear that different people just have different carb tolerances.  Some folks can eat a lot of carbs and still maintain healthy weight and carry few of the inflammatory side effects of a high-carb diet.  These individuals aren’t superhuman; it’s just that they are eating the right carbs and their metabolism hasn’t been hijacked and made insulin resistant by processed foods and a constant barrage of sugar.

So I set out to explore my own metabolism and see how I handle a variety of carbohydrates by doing Robb Wolf’s 7-day carb test.  Watch the video on his site or read his book to learn more, but in short, the test involves eating 50 grams of net carbohydrates from a single source under semi-controlled conditions and tracking both the subjective (how you feel) and objective (blood tests) results.  A “passing” results is any blood sugar reading less than 115 at 2 hours.  The test itself is quite simple, although it does require a little planning and discipline.  Oh, and a glucometer and a few drops of blood.  Don’t forget that part!  Now on to the test…

Set up:

You will need a basic glucometer.  These are the types of things you see sold behind the counter at Walgreens or CVS and thought you’d never need unless you became diabetic.  Precision Xtra is one option that does both blood sugar (glucose) and ketones, and although I recommend it, the strips are expensive and no better than you can get for a fraction of the price.  In fact, I have two units: the Precision Xtra that I use for ketones (more on this in a future post) and the cheapo Reli-On brand for glucose.  Of course you’ll also need the strips and lancets, which can be found on the cheap at you local discount drug store or Amazon.  Now you’re ready to get cooking!

Food prep:

Get the list from Rob Wolf (or pick any carb source you want to test and figure out how much 50g of net carbs will be).  Go shopping.  Cook food.  Done.

In all seriousness it’s pretty easy, but you do have to realize a few things.  First off, you need to eat the single source of carbohydrate.  So when it says “white rice” that means you just eat white rice.  Nothing else, except maybe a little salt or black pepper.  Likewise, you can’t have anything else to eat or drink in the ~8 hrs prior or during the 2 hr test phase.  Even a splash of cream in your coffee can alter insulin secretion and therefore your blood sugar results.  Presuming you do the test in the morning upon waking, I think it’s OK to drink a little black coffee or water, but nothing else.

Results:

1. White rice: Whenever we go out for Japanese, I always crave the rice. Whether it be fried rice or sushi rice, I can’t get enough of the umami goodness.  That is nothing like what I experienced here.  Plain white rice sucks!  It was a task just getting this stuff down without the tamari and sesame goodness to which I am accustomed (but it paled in comparison to some other carbs I tested).  Not surprisingly, my glucose spike was higher with rice, but I still “passed” at the 2 hour mark.
2. Blueberries: Although it was a Herculean feat to eat nearly 3 cups of blueberries I felt relatively fine afterwards and my glucose never made much above 100 settling in at 90 to 2 hours post prandial.  PS: I did not turn blue, although I felt like I was going to.
3. Black beans: I dreaded this one, not so much for the taste but more for the bloating and cramping I would inevitably experience afterwards. To my surprise, they actually tasted pretty good plain (with a dash of salt) and I had no such GI upset afterwards.  Glucose levels were almost normal afterwards.
4. White potatoes (baked): This is where the wheels came off.  Previously, I wrote about how I felt in the hours after ingesting lots of potatoes and the bloating, headaches, and generally crappy feeling I experienced.  My glucose levels were highest here, but I still “passed” the test at 2 hours.
5. Sweet potatoes (baked): This was one of the easiest all around. In fact, it was the only 50g test food I ate that I actually enjoyed.  Now, I could have sufficed with ½ cup instead of 1.5 cups, but they definitely taste good plain and downright delicious with a little salt.  Who needs butter?  At one hour glucose was only 114 and I felt fine, and by 2 hours I was down to my usual mid-90’s.
6. Bananas: probably the easiest to eat and, just like sweet potatoes, I felt absolutely fine afterwards. I was a bit surprised by the lack of glucose spike at 1 hr, especially given how sweet bananas are.
7. You might notice my 7 day test is actually a 6 day test.  I felt that I had accomplished what I set out to do so I stopped here.  You could do more or less.  I’ll probably go back later and test a few more options like corn or even experiment with something containing gluten, but since grains aren’t a part of my diet its not really necessary.

Conclusions:

Yes, in some ways this experiment is predictable.  You could argue it is essentially recapitulating the principle of the glycemic index.  But it’s important to do this type of test because individuals do different in the way they processed carbohydrates.  Although I had higher spikes in blood glucose with white rice and white potatoes, I felt completely different after each.  Although the “7 day carb test” was pretty easy, I learned a lot about myself and my metabolism.  I witnessed first-hand that not all carbs are created equal.  There are some that will make me feel like crap and others will hardly raise my blood sugar.  I also learned that after years of eating low carb, I have excellent insulin sensitivity—that is, my body responds quickly and appropriately to large volumes of carbohydrate by secreting insulin.  Since poor insulin sensitivity is the very cause of type II diabetes, I am happy to know that I’m not at risk.

Another important lesson learned is that we are so accustomed to processed foods.  I could easily eat 50g of carbs from potato chips or French fries, and still probably want more.  But it was almost impossible to stomach two plain dry potatoes or a gigantic bowel of berries.  Going through this exercise gave me a new appreciation for the importance of eating whole, unprocessed foods.  If you don’t want it in its natural state, perhaps you shouldn’t be frying it in oil and dousing it with seasonings just to make it hyper-palatable.

But the foremost lesson I learned was to stop fearing carbohydrates.  If my blood sugar barely rose after eating massive quantities of berries—and if you’re wondering 2.5 cups of berries is enough to make you want to gag—why should I worry about eating a few handfuls with my breakfast or after dinner?  For the past year it’s been one of my goals to consume a bit less protein.  I had been resistant to adding carbohydrates back into my diet since I’ve done so well with low carb; however, after doing this test myself I am a little bit more comfortable trying.  My goal is to keep protein in the range of 0.5 to 1 g per pound of lean body weight, and adding back some healthy carb sources will make that easier.  For Paleo enthusiasts like me, its refreshing to know which carb sources are agreeable—both subjectively and metabolically—and add those back in to moderate protein intake and interject a little variety.

~Brendan