Food Labeling. Percentages don't add up..

Posted by bobunderwood @bobunderwood, Oct 29, 2021

My doctor diagnosed "pre-diabetes" last year. He prescribed a CGM, and I have been controlling my blood sugar with diet. My average glucose for the past 90 days is 108, and I rarely spike over 150, My AIC was within normal range at my last check-up, so I guess I'm eating right.

I have a question about food labeling. I just looked at the carb content of several items in my pantry. They all list a grams per serving and percentage of RDA. But when I calculate the percentages, I get different RDA's. For example:

mix nuts: 7 grams = 3% (7 is 3% of 233)
peanut Butter: 7 grams, (7 is 2% of 350)
mozzarella cheese: 2 grams, 1% ( 2 is 1% of 200)
no sugar added pizza sauce: 5g, 2% ( 5 is 2% of 250)
canned kidney beans: 19g, 7% (19 is 7% of 271)
canned refritos: 15g, 5% ( 15 is 5% of 300)
"Palmini" spaghetti substitue: 4 g, 1% ( 4 is 1% of 400)
macaroni: 42g, 15% (42 1s 15% of 280)

I used the formula RDA = grams per serving/ percent RDA.
Example: Mix nuts =7g/0.03= 233g = RDA

Why is there such a difference? Why aren't the food manufacturer's using the same RDA? What is the real RDA?

Interested in more discussions like this? Go to the Diabetes & Endocrine System Support Group.

Colleen Young, Connect Director | @colleenyoung | Oct 30, 2021

Welcome to Mayo Clinic Connect, @bobunderwood. RDA or Recommended Daily Allowances have been replaced by Daily Value (DV), the new term used on food labels. %DV is explained in detail in the article from the FDA

- How to Understand and Use the Nutrition Facts Label https://www.fda.gov/food/new-nutrition-facts-label/how-understand-and-use-nutrition-facts-label
Here's an excerpt:
"Do you need to know how to calculate percentages to use the %DV? No, because the label (the %DV) does the math for you! It helps you interpret the nutrient numbers (grams, milligrams, or micrograms) by putting them all on the same scale for the day (0-100%DV). The %DV column doesn't add up vertically to 100%. Instead, the %DV is the percentage of the Daily Value for each nutrient in a serving of the food. It can tell you if a serving of food is high or low in a nutrient and whether a serving of the food contributes a lot, or a little, to your daily diet for each nutrient."

I'm not an expert in food label interpretation, so allow me to bring fellow members @jacannie6 @rambler and @dorisena into this discussion as well as dietitian @taraschmidt. Hopefully they can shed some light.

Bob, kudos to you for getting ahead of diabetes through diet. Have you made any other lifestyle changes?

dorisena | @dorisena | Oct 30, 2021

I printed out the info for this label study and it is a lot to learn.. it is necessary to learn first how many carbs are recommended for a person to eat each day, and then count carbs in each meal to maintain that level. When you have a handle on that eating then, move on to understanding and using theis percentage label to improve deficiencies in nutritients and eat a balanced diet. I had to write down what I ate at first to learn how much to eat. This method is the next step and is a bit much for beginners, but well worth the learning and following to get to better health. Take it a day at a time, and you will soon enjoy calculating and eating for better control and good health. Dorisena

John, Volunteer Mentor | @johnbishop | Oct 31, 2021

@bobunderwood and @dorisena - There is another discussion and group that you may be interested in viewing. I have also been diagnosed with prediabetes and I'm concerned about carb intake so I've been using intermittent fasting and recently started working on reducing the amount of carbs.

-- Low-carb healthy fat living. Intermittent fasting. What’s your why?: https://connect.mayoclinic.org/discussion/low-carb-healthy-fat-living-intermittent-fasting-whats-your-why/
-- LCHF Living & Intermittent Fasting group list of discussions: https://connect.mayoclinic.org/group/lchf-living-intermittent-fasting/

Tara Schmidt | @taraschmidt | Nov 1, 2021

In reply to @colleenyoung "Welcome to Mayo Clinic Connect, @bobunderwood. RDA or Recommended Daily Allowances have been replaced by Daily..." + (show)

Hi @bobunderwood . First of all, congrats on taking some great steps to improve your health. It sounds like you are already making progress. When we teach about food labels related to diabetes, we almost always have patients look more so at the grams of total carbohydrates in a product more than anything. If you have pre-diabetes, you may not even need to do this! The Plate Method is the most common education (in addition to weight management if that is relevant to you) we provide. Find that method here: https://www.myplate.gov/

I truly would not bother with percentages, as these are not specific to you and your nutrient needs. If you are curious what your needs are (grams of carbohydrates per meal, etc) consider asking your physician for a referral to a registered dietitian.

Lastly, here's an article on Connect that was posted last year on label-reading: https://connect.mayoclinic.org/blog/weight-management-1/newsfeed-post/key-points-when-reading-nutrition-labels/