Fact-Check: Are the dietary guidelines the cause of the obesity epidemic?

Recently, Dr. Jordan Peterson made this claim about Western dietary recommendations:

“The dietary recommendation to prioritize carbohydrates produced a veritable epidemic of obesity and diabetes…”

While accepting this statement at face value is tempting, I’d like to look a little deeper at this assertion and share why I disagree. 

As I shared on IG, there are four reasons Dr. Peterson’s statement doesn’t stand up to scrutiny. First, very few people are actually following the guidelines, as you can see in the chart below. 


 In general, most people eat too few fruits, vegetables, and whole grains and too many refined grains, added sugar, and empty calories, in clear opposition to the dietary guidelines. (1) It’s hard to blame the guidelines for obesity when very few people adhere to them. 


Second, obesity has been increasing long before the dietary guidelines were established. For the last 100 years, the average BMI has been on the rise in the US. (2) By the time the dietary guidelines were first published in 1980, obesity was already developing into a public health concern.


Third, Japan has dietary guidelines that, while not identical, closely align with the Australian and US dietary guidelines, emphasizing grains and vegetables as the base of a healthy diet. Yet, Japan has some of the lowest obesity rates in the world. Even more telling, when native Japanese move to the US, their obesity and chronic disease risk soon match that of Americans. (3)


Fourth, many randomized, controlled trials, the gold standard of scientific evidence, show adherence to the dietary guidelines produces positive health benefits. When people move from the standard American diet and align with the dietary guidelines, they lose weight and reduce their risk of disease. (4)


I understand the temptation to blame the health “authorities” for the current obesity and chronic disease crisis. The dietary guidelines are not perfect and discussing how they could be better is a worthwhile conversation. But in the absence of widespread adherence to the guidelines, they’re clearly not the culprit.

So, what’s actually the cause of the obesity epidemic? While it would be much more convenient to point a finger at a single food group or recommendation, the truth is that a complex storm of factors drive Western dietary patterns. (5, 6)

  • The intelligent marketing of hyper-palatable processed foods, especially to children
  • The current food environment and social/marketing cues 
  • Lack of education
  • Loss of cooking skills 
  • Price promotion of processed foods

If I were to try and really simplify a clear dietary recommendation, this is what I would say:

“Eat for your microbes” 

Our microbes thrive on prebiotics which are only found in plants and most concentrated in whole or minimally processed plants – fruits, vegetables, whole grains, legumes, nuts, seeds, and herbs/spices. If you always think about eating for their benefit, it’s hard to go wrong.

And you may just end up following a diet close to the dietary guidelines while enjoying the best health of your life. 


  1. Krebs-Smith SM, Guenther PM, Subar AF, Kirkpatrick SI, Dodd KW. Americans do not meet federal dietary recommendations. J Nutr. 2010;140(10):1832-1838. doi:10.3945/jn.110.124826
  2. https://www.nber.org/papers/w16252
  3. Yoneda M, Kobuke K. A 50-year history of the health impacts of Westernization on the lifestyle of Japanese Americans: A focus on the Hawaii-Los Angeles-Hiroshima Study. J Diabetes Investig. 2020;11(6):1382-1387. doi:10.1111/jdi.13278
  4. Reidlinger DP, Darzi J, Hall WL, et al. How effective are current dietary guidelines for cardiovascular disease prevention in healthy middle-aged and older men and women? A randomized controlled trial. Am J Clin Nutr. 2015;101(5):922-930. doi:10.3945/ajcn.114.097352
  5. Hall KD. Did the Food Environment Cause the Obesity Epidemic?. Obesity (Silver Spring). 2018;26(1):11-13. doi:10.1002/oby.22073
  6. Swinburn BA, Sacks G, Hall KD, et al. The global obesity pandemic: shaped by global drivers and local environments. Lancet. 2011;378(9793):804-814. doi:10.1016/S0140-6736(11)60813-1
  7. https://ourworldindata.org/obesity
  8. https://www.obesityevidencehub.org.au/ 
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