Background: Eating too much processed food is believed to lead to obesity. But the effect of processed food on energy intake has not been carefully studied. Researchers want to study people s diets for 4 weeks and do specialized tests of the effects. Participants will get two diets. They will have the same calories and nutrients, but one diet will be unprocessed food and the other will be ultra-processed. Objective: To better understand how processed and unprocessed foods affect daily food consumption and how the body handles blood sugar. Eligibility: Healthy adults ages 18-50 who have stable weight and can exercise Design: Participants will not eat for 12 hours. Then they will be screened with: * Medical history * Physical exam * Heart and blood tests * Resting energy expenditure test (REE). A hood will collect air exhaled while lying down for 30-40 minutes. * Psychiatric questions * Questions about mood, eating, sleep, and socioeconomic status * 20-minute stationary biking Female participants will have a urine pregnancy test. Participants will stay in the clinic for 4 weeks. For 2 weeks they will get a processed diet. For the other 2 weeks they will get an unprocessed diet. Participants cannot use the study period to gain or lose weight. Participants will have: * Meals and snacks provided * Daily exercise * Blood, urine, and saliva tests * To drink a special water and a very sweet liquid * REE * Scans and X-rays * To wear activity monitors and a device to measure blood sugar * Several 24-hour periods in a room that measures oxygen and carbon dioxide * Repeats of screening questions * Questions about hunger and meals * Sleep monitoring * Taste tests
Overconsumption of foods that result from extensive industrial processing is believed to contribute to the development of obesity. Ultra-processed foods now represent most of the calories consumed in America and their contribution to overall diet has increased in parallel with the rise in the prevalence of obesity over the past several decades. While such correlations are suggestive, the effect of industrial processing per se, independent of dietary macronutrient composition, on ad libitum energy intake has not been carefully investigated. Therefore, we will conduct feeding studies in adult men and women to investigate the differences in ad libitum energy intake resulting from consuming test diets for a pair of 2-week periods in a randomized, crossover design during a single 4-week period. The test diets presented to participants will be matched for calories, macronutrient composition, sugar, fiber, and sodium, but one diet will be composed of ultra-processed foods whereas the other diet will be unprocessed foods.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
20
Consuming ultra-processed diet over a 2-week period
Consuming unprocessed diet over a 2-week period
National Institutes of Health Clinical Center
Bethesda, Maryland, United States
Ad Libitum Energy Intake
Ad libitum energy intake averaged over 14 days for each diet, measured in kilocalories (kcal) per day.
Time frame: 14 days
Change in Body Weight
Change in body weight from baseline to day 14 for each diet, measured in kilograms (kg)
Time frame: Baseline and day 14
Change in Fat Mass
Change in body fat mass from baseline to day 14 for each diet, measured in kilograms (kg). Body fat mass was measured using Dual-energy X-ray absorptiometry (DXA) measurements.
Time frame: Baseline and day 14
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