
This is an opinion piece connected to a very interesting study (Trends in Dietary Carbohydrate, Protein, and Fat Intake and Diet Quality Among US Adults, 1999-2016 – see this post) that’s very timely, given that the revision of the Dietary Guidelines for Americans is currently underway.
I created a few charts from the data (above and below) that show trends for sources of protein (above), and sources of carbohydrates (below) over the last 20 years. Not much change in either metric since 1999. What has changed, since 1965, is that carbohydrates now provide the majority of energy in the Standard American Diet (SAD), compared to fat.

I would say I agree with the editorial, some progress, with lots of disappointment.
The evidence of some improvement in diet quality reported by Shan and colleagues offers reasons to hope that continued national,local, and individual efforts encouraging population-wide adherence to the US Dietary Guidelines for Americans could subsequently improve health and delay onset of chronic disease.Van Horn L, Cornelis MC. US Dietary Guidance—Is It Working? JAMA [Internet]. 2019 Sep 24;322(12):1150. Available from: https://jamanetwork.com/journals/jama/fullarticle/2751694
The piece’s author is Linda Van Horn, PhD, RDN, LD, who is a member of the Dietary Guidelines for Americans Committee.
Saturated fats comment – forward looking statement?
While any improvement in national dietary quality represents a positive development in adherence to recommended dietary guidelines, the continued excessive intake of saturated fats, sugar, salt, and refined grains is of major concern.Van Horn L, Cornelis MC. US Dietary Guidance—Is It Working? JAMA [Internet]. 2019 Sep 24;322(12):1150. Available from: https://jamanetwork.com/journals/jama/fullarticle/2751694
…understood that this is concerning to some, however, this is an official topic and question being examined by the Committee. Is the quote above a forward looking statement to the outcome of the scientific review?
Saturated fats
What is the relationship between saturated fats consumption (types and amounts) during adulthood and risk of cardiovascular disease?Proposed Topics and Scientific Questions Posted for Public Comment | Dietary Guidelines for Americans and Dietary Fats and All-Cause Mortality | Dietary Guidelines for Americans
No question these are important topics, glad they are being reviewed thoroughly.


Conflicts of Interest
- Mine – See my disclosures page (short version, I have none)
- This piece
Dr Van Horn reported being a member of the 2020 US Dietary Guidelines Advisory Committee. No other disclosures were reported.
- The related article
Dr Rehm reported receipt of personal fees from Nestec Ltd and the Dairy Management Institute. Dr Hu reported receipt of grants from the CaliforniaWalnut Commission and personal fees from Metagenics, Standard Process, and Diet Quality Photo Navigation. Dr Mozaffarian reported receipt of grants from the Gates Foundation; receipt of personal fees from GOED, Nutrition Impact, Pollock Communications, Bunge, Indigo Agriculture, Amarin, Acasti Pharma, Cleveland Clinic Foundation, America’s Test Kitchen, and Danone; scientific advisory board membership from Elysium Health (with stock options), Omada Health, and DayTwo; and receipt of publication royalties from UpToDate; in addition, Dr Mozaffarian reported holding patents US8889739 and US9987243 listing Dr Mozaffarian as a coinventor for use of transpalmitoleic acid to prevent and treat insulin resistance, type 2 diabetes, and related conditions as well as reduce metabolic risk factors. No other disclosures were reported.
For a previous reference related to this work
Since this issue is coming up in other venues for other studies, I noted this conflict of interest from one of the authors for previous work on this topic. I would also call these significant conflicts.
Dr Mozaffarian reported receiving honoraria from Nutrition Impact, Haas Avocado Board, Amarin, and AstraZeneca; personal fees from Bunge, Life Sciences Research Organization, and Boston Heart Diagnostics; serving on advisory boards for Unilever North America (ended 2014); and chapter royalties from UpToDate. No other disclosures were reported Rehm CD, Peñalvo JL, Afshin A, Mozaffarian D. Dietary intake among US Adults, 1999-2012. JAMA – J Am Med Assoc [Internet]. 2016 Jun 21;315(23):2542–53. Available from: http://jama.jamanetwork.com/article.aspx?doi=10.1001/jama.2016.7491
References
1. Van Horn L, Cornelis MC. US Dietary Guidance—Is It Working? JAMA [Internet]. 2019 Sep 24;322(12):1150. Available from: https://jamanetwork.com/journals/jama/fullarticle/2751694
2. Shan Z, Rehm CD, Rogers G, Ruan M, Wang DD, Hu FB, et al. Trends in Dietary Carbohydrate, Protein, and Fat Intake and Diet Quality Among US Adults, 1999-2016. JAMA [Internet]. 2019 Sep 24 [cited 2019 Sep 30];322(12):1178. Available from: https://jamanetwork.com/journals/jama/fullarticle/2751719