Answer Key

A few days ago I posted this problem on my Facebook page for this blog

Let’s do diabetes math together. Based on nutritional information presented, solve the following problems. Show your work.
1. How many grams of carbs are in each popped cup?
2. How many grams of carbs are in one bag of popped popcorn?
3. If you estimate 17g of carbs for entire popped bag, and your insulin to car ration is 1 unit per each 4.2 carbs, what’s the total amount of insulin needed to cover all 17g?
4. Based on your answer to #2, how many units of insulin should you have actually given?
5. In a short paragraph, describe why blood sugar was nearly 400. Bonus: what prevented it from being even worse?
6. Explain WHY the heck Costco had to make this so complicated? Bonus points will be awarded for creative responses and GIFs.

Quick backstory: V went to hang out to a friend’s house and ended up with BG of nearly 400. She swore to me she counted carbs accurately. One of the thing she had was some popcorn. A couple of days later she made same popcorn. Out of pure curiosity I looked at the nutrition label. My brain broke.

Intuitively I knew that V miscalculated carbs big time. But by how much? The accurate carb count was eluding me. How many carbs per cup? How many cups in each bag? Normally we are pros at counting carbs. This labeling had me thoroughly stumped. After thinking it through some more and asking around, it’s only fair that I give you my answer key to the problem.

  1. The column on the right clearly states that each popped cup contains 3 g. of carbs. This, I think, is a lie. Rule of thumb has always been count 5 g. of carbs per each popped cup of popcorn. There’s nothing in this popcorn that would make it lower in carbs. I don’t know who is the ultimate authority on popcorn nutrition facts, but even this pro-popcorn website, which clearly paints it as God-sent food, gives each popped cup a 6 g. count.
  2. Since there are 2.5 servings per bag, and one serving makes 5.5 cups, that’s 13.75 cups X 3 g  per cup, which is 41.25 g in one bag. Alternatively, per left column, 17 g. in each serving times 2.5  = 42.5 g. per bag. Close enough. Except if we use the rule of thumb carb count, then we get 68.75g per bag, which is a hugely different.
  3. Best on the 17 g. estimate, 17 divided by 4.2  =  4.05 units of insulin.
  4. Best case scenario, V underestimated by a whopping 24.25 carbs. 41.25 divided by 4.2  =  9.8 units of insulin. More than double (!!!) than what she gave herself. Worst case scenario, if we use 5 g. per popped cup count, then she should have given 16.6 units of insulin for the whole bag.
  5. V’s blood sugar was nearly 400 because due to confusing labeling she did not count her carbs correctly and gave herself far less insulin than she actually needed. (Fun fact: popcorn used to be “free food”. When V’s carb rations were 1:15, it meant that she could have one cup of popcorn without needing to give insulin. Those days are gone, gone, gone.) Now, for bonus points, why it wasn’t even worse.
    1. Loop! Loop predicted a much higher BG based on what was actually happening and tried to hold it back with a bucket worth of basal insulin.
    2. The serving size does not appear to be correct either. For the sake of science and not having anything to do with wanting to eat some popcorn, I popped a bag tonight. Using crude measuring tools such as a measuring cup and a big bowl, I transferred popcorn out of the bag into the bowl one cup at a time. I counted roughly 9-10 cups. Nowhere near 13.75. So perhaps V’s carb count was slightly less off.

As to question 6, beats me! But here’s a very relevant meme. Now, give me ALL the bonus points!