by Marion Nestle
Sep 9 2024

Industry-funded studies of the week: Walnuts again and again

The walnut industry must be desperate for greater market share.  Walnuts are great and make a terrific snack if you don’t eat too many of them (calories!).  But this is one-food research.  Can one food really make an important difference to health (yes, if you are seriously deficient in essential nutrients but most Americans are not).

One-food research has to be about marketing more than science.

To wit:

A Cross-Sectional Study on the Association of Walnut Consumption with Obesity and Relative Fat Mass among United States Adolescents and Young Adults in NHANES (2003–2020).  2024 Current Developments in Nutrition.  DOI: https://doi.org/10.1016/j.cdnut.2024.104407

Conclusions: For adolescents girls and young women, dietary intake of walnuts combined with other nuts has the strongest inverse association with measures of obesity.

Funding: This study was funded by the California Walnut Commission.

Comment

The study does not find an association between eating walnuts and obesity in adolescents.  I would not expect it to.  People do not eat that many walnuts.  They get most of their calories from fast and ultraprocessed foods.

The California Walnut Commission would like you to think the calories in walnuts do not count.  In a press release, it points out

Nuts, including walnuts, are nutrient dense and considered a key component of many recommended dietary patterns, including the Mediterranean and vegetarian diets. They are also recommended for daily consumption in the latest U.S. Dietary Guidelines.3 Despite the recommendations, nuts remain under-consumed by the U.S. population,3 perhaps due to nuts being calorie dense, leading to potential concerns that including nuts in the diet could promote weight gain. But new research suggests people, especially Gen Z and millennials, should reconsider nuts, like walnuts.

All true, but nuts in general, not specifically walnuts.  This is about increasing the market share for walnuts as opposed to other nuts.