Effects of Ultra Processed Food on Intestinal Energy Harvest

Overview

Ultra processed food is everywhere in modern society and may contain multiple ingredients that affect the way participants' bodies store energy. Some studies have shown that eating a diet high in ultra processed foods leads to weight gain, but these foods have not been studied enough to understand why. Recently, the gut microbiome has become a potential way to measure energy balance in the human body; this is done by measuring how many calories are in the stool. The investigators propose to test a very high ultra-processed food diet where 80% of calories are coming from ultra processed food and a low ultra processed food diet where 20% of the calories are coming from ultra processed food. This study will compare stool sample energy content of the two diets.

This study will recruit people with obesity who are otherwise healthy to participate in this study. Each person will go through baseline testing before starting any of the diets. This consists of one blood draw, one metabolic test which requires each person to remain awake in a small, enclosed room that measures oxygen and carbon dioxide consumption, and one body composition test. Participants will also meet with a study dietitian to review their diet, how to track their diet, and how to collect and ship the stool samples. Each person will be assigned to either 80% or 20% level of ultra processed food in the diet to start and will continue this diet for two weeks. After the first diet phase, each participant will enter a washout period where they will return to eating however they wish and will not need to participate in any research activities. After the two weeks, each participant will return to begin another series of tests and begin the second two-week diet phase. The whole study will take approximately 9 weeks to complete.