Refined carbohydrates account for approximately 42% of total calories in the average American diet.
Notes on verification
Figure derives from a single peer-reviewed JAMA study (Shan et al., 2019) using NHANES data, widely reported by Tufts, Harvard, and major media. Note the study's 'low-quality carbohydrates' category (refined grains, starchy vegetables, added sugars) is slightly broader than 'refined carbohydrates' alone, but this framing is standard in secondary coverage.
Sources
- Cardiovascular Disease: 4 to 6 Servings of Whole Grains May Lower Risk (healthline.com)
- https://www.medicalnewstoday.com/articles/326456 (medicalnewstoday.com)
- https://now.tufts.edu/2019/09/24/report-card-diet-trends-low-quality-carbs-account-42-percent-days-calories (now.tufts.edu)
- https://hsph.harvard.edu/news/report-card-on-diet-trends-low-quality-carbs-account-for-42-percent-of-a-days-calories (hsph.harvard.edu)
- https://www.today.com/health/how-eat-healthy-americans-still-eat-too-many-carbs-saturated-t163230 (today.com)
- https://theconversation.com/a-nutrition-report-card-for-americans-dark-clouds-silver-linings-156200 (theconversation.com)
- https://pubmed.ncbi.nlm.nih.gov/31550032/ (pubmed.ncbi.nlm.nih.gov)
- https://dx.doi.org/10.1001/jama.2019.13771 (dx.doi.org)