Review of recent study published in Cell Metabolism:
Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake.
Kevin D. Hall 5 Alexis Ayuketah Robert Brychta Hongyi Cai Thomas Cassimatis Kong Y. Chen Stephanie T. Chung Elise Costa Amber Courville Valerie Darcey Laura A. Fletcher Ciaran G. Forde Ahmed M. Gharib Juen Guo Rebecca Howard Paule V. Joseph Suzanne McGehee Ronald Ouwerkerk Klaudia Raisinger Irene Rozga Michael Stagliano Mary Walter Peter J. Walter Shanna Yang Megan Zhou
Published:May 16, 2019
Comments by Dr. Robert Lustig
A calorie is a calorie is a calorie; eat less and exercise more; any calorie can be part of a balanced diet. These are the mantras of the processed food industry. But are they real or fake news?
Hall and his NIH group attempted to answer this question with a 2-week crossover demand feeding study comparing the effects of real food (NOVA system class I, developed by Monteiro et al at the University of Sao Paolo) with ultra-processed food (NOVA system class IV). Hall locked up 20 subjects at the NIH Clinical Center, threw away the key, and fed them in random order and for 2 weeks at a time an ad lib processed food diet (more carbohydrate, less fiber) or an ad lib real food diet (less carbohydrate, more fiber). The two diets were matched for presented calories, sugar, fat, fiber, and macronutrients. Hall tracked food intake, body weight, energy expenditure, and baseline and glucose-stimulated hormonal parameters.
The ultra-processed food diet resulted both in weight gain and 508 calories per day greater intake (mostly carbohydrate) than the real food diet, which resulted in weight loss. The only things that distinguished the ingestion patterns were higher carbohydrate and less fiber in the ultra-processed diet. Finally, body weight changes correlated with changes in energy intake.
Bottom line: like other studies which preceded it (eg, the DIETFITS study), this study shows that real food works, and processed food doesn’t — take it to the bank. Real food resulted in fewer calories consumed, but we can’t infer that the effect was due to increased fiber (fewer calories absorbed); decreased energy density; reductions in carbohydrate; reductions in insulin and changes in leptin signaling; feeding the microbiome; and/or increased satiety.
And what about the food industry’s real versus fake news? Can we discern if, and which, macronutrients are the bad guys? What really reduced caloric intake? Unfortunately, this study was not designed or powered to assess whether certain macronutrients (like starch, fat, fructose) altered food intake apart from its caloric equivalent. Hall is a thermodynamics guy—and a calorie is always a calorie. So, don’t expect any other seminal answers out of this one.
Commentary originally published in PracticeUpdate!
Lustig RH. Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of ad Libitum Food Intake. PracticeUpdate website. Available at: https://www.practiceupdate.com/content/ultra-processed-diets-cause-excess-calorie-intake-and-weight-gain/84403/65/8/1. Accessed July 11, 2019
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