In an ongoing study in press with the journal Contemporary Clinical Trials, researchers examine how consuming ultra-processed foods (UPF) affects physiological processes related to energy intake (EI) and reward processing.

Chubby and obesity proceed to rise world wide, leading to varied health issues reminiscent of heart disease. Scientists have found that even young people (age 18 to 30) who’re at a medically advisable weight are at a high risk of transitioning to obese or obesity over the following quarter-century.

Poor dietary practices amongst adolescents and young adults in the USA have been well documented. Greater than two-thirds of their EI is assumed to return from UPF, with little to no whole foods. Scientists are concerned that these foods can modify how people make diet-related decisions and result in obese and obesity.

Study: The influence of ultra-processed food consumption on reward processing and energy intake: Background, design, and methods of a controlled feeding trial in adolescents and young adults. Image Credit: Celso Pupo / Shutterstock

UPF foods have high rewards but little nutrition

Research on humans and rats has shown how processed foods can affect the dopamine system within the brain. Rats fed bacon and frosting gained weight rapidly, which was regarded as related to lower functioning of the striatum’s D2 dopamine receptors (D2R) present within the striatum, an area within the brain related to moderating food intake and reward.

Animals fed high-sugar diets and humans exposed to high-fat, high-sugar foods show similar effects. The finding that humans with high body mass index (BMI) have lowered D2R function points to the role of UPF in increased EI, which could lead on to obese and obesity.

Nevertheless, just one trial has examined this relationship in adult humans, and no research has focused on how UPF consumption in early maturity could change brain chemistry and modify how people perceive reward from food.

These changes, going down in the course of the critical transition between childhood and maturity, have implications throughout one’s life as cognitive processes like inhibitory control mature at this age. Thus, UPF could modify executive function (EF) related to inhibitory control, working memory, and cognitive flexibility, resulting in people eating more when not hungry.

Exploring how UPF affects EF in young adults

The continued clinical trial will recruit participants between the ages of 18 and 25 who’re either sedentary or recreationally energetic. Individuals with food allergies is not going to be included. Through the recruitment process, physical examinations and dietary recall information will probably be assessed. Participants can even be screened with a mock functional magnetic resonance imaging (fMRI) scan to make sure they will not be claustrophobic.

At baseline, researchers will collect data on body weight and composition, conduct an fMRI, and ask participants to finish delay discounting tasks and cognitive EF tasks. They estimate that they are going to require 32 participants in the beginning of the study to account for attrition and be certain that they’ve no less than 26 participants and sufficient statistical power for causal inference.

All of the participants will then be exposed to 2 diets, each for 2 weeks. In a single eating regimen, participants will receive 81% of their EI from UPF, while the opposite eating regimen will contain no UPF. These diets will probably be designed to be similar when it comes to overall quality, nutrients, texture, and palatability and formulated for weight maintenance. They’ll comprise 15% protein, 35% fat, and 50% carbohydrates.

Participants will devour their breakfast on the laboratory from Monday to Saturday and be given food for the rest of the day. Meals for Sundays will probably be provided upfront. Any leftover food will probably be returned to the laboratory, and consumption, deviance, and compliance data will probably be recorded.

Along with meals, participants will probably be offered a selection of snacks and buffet meals to evaluate their preference between UPF and non-UPF foods. There will probably be a four-week “washout period” between the 2 controlled feeding periods. After each feeding period, one other fMRI will probably be taken, and physical measurements and cognitive functioning will probably be observed. For 4 days of every eating regimen, participants will wear an accelerometer for physical activity measurements.

Researchers will study the mechanisms by which UPF modifies reward processing. They’ll explore the body’s blood oxygenation level-dependent (BOLD) response, in addition to EI between meals, using statistical methods reminiscent of evaluation of variance (ANOVA) with mixed effects and generalized linear mixed models.

They hypothesize that UPF foods will weaken the BOLD response within the ventromedial prefrontal cortex and the striatum, that are reward centers of the brain. Additionally they expect the UPF eating regimen to extend the preference for UPF food items, in addition to EI, between meals. Finally, they theorize that UPF foods will lower EF performance by weakening inhibitory control.

Implications of the study

Although emerging research highlights the opposed health effects of UPF, business food consumption stays broadly popular. Researchers imagine that these foods are addictive and that they weaken our natural ability to manage EI. Understanding how these foods modify decision-making abilities and brain chemistry is vital to formulating simpler public health guidelines and regulations for business food firms to advertise healthier diets.