How Are Ultra-Processed Foods Fueling the Obesity Epidemic?

TOPLINE:
The consumption of ultra-processed foods (UPFs) leads to weight gain and increased energy intake, perhaps in part by faster eating and less chewing compared with minimally processed and freshly prepared meals.
METHODOLOGY:
Many observational studies have linked eating UPFs to an increased risk for obesity and obesity-related health problems, but there is little evidence establishing the causality, and it’s not clear exactly how UPFs contribute to weight gain.
The researchers conducted a randomized, open-label, crossover study to compare the effects of UPFs and non-UPFs in nine otherwise healthy Japanese men with overweight or obesity (mean age, 29.7 years; mean body mass index, 27.4).
During each diet period, the men were admitted as inpatients in the Clinical Trial Ward Department at the University of Tokyo Hospital, Tokyo, Japan, and were assigned to consume either UPFs or non-UPFs for 1 week, followed by a 2-week washout period, after which they crossed over to the alternate diet for another week.
Meals were matched for total energy and macronutrient levels, and participants were allowed to eat as much as they wanted within a 60-minute time limit per meal. Matched snacks and water were also available for men on each diet.
The primary outcome was the difference in body weight change between the periods of consumption of UPFs and non-UPFs. Secondary outcomes included daily energy intake, eating rate, chewing frequency, and metabolic profiles.
TAKEAWAY:
The participants gained an additional 1.1 kg weight during the period of consuming UPF’s compared with when consuming non-UPFs (P = .021).
Average daily energy intake was 813.5 kcal higher during the UPFs consumption week vs the non-UPFs week (P = .0041), with a statistically significant higher energy intake at dinner (P < .0001) and lunch (P = .0009) but not at breakfast or snack times.
The eating rate was faster, both by calories and weight per minute, while the chewing frequency was lower during the week of consuming UPFs vs the non-UPFs week.
The blood levels of triglyceride, aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyl transpeptidase increased significantly during the week of consuming UPFs but not when consuming non-UPFs.
IN PRACTICE:
“Consumption of UPFs causes significant weight gain,” the study author wrote. “Medical nutritional therapy focused on reducing the consumption of UPFs could be an effective strategy for preventing obesity.”
SOURCE:
The study was led by Shoko Hamano, MD; Mika Sawada, PhD; and Masakazu Aihara, PhD, from The University of Tokyo, Tokyo, Japan, from the University of Tokyo Hospital. It was published online in Diabetes, Obesity and Metabolism.
LIMITATIONS:
The study’s small sample size of nine participants and inclusion of only young Japanese men with overweight or obesity limit the generalizability of the findings. The short duration of the intervention period did not allow for assessment of the long-term effects of UPF consumption.
DISCLOSURES:
The study was supported by the Ministry of Education, Culture, Sports, Science and Technology of Japan. The authors declared no conflicts of interest.
This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.
 
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