Ultra-processed food and appetite in adults 18-25

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Ultra-processed food and appetite in adults 18-25

Assortment of peanut brittle pieces scattered on white background

In the first controlled-feeding trial in adults 18-25, the full sample showed no difference in test-meal intake after two weeks of ultra-processed food. Only the 18-21 group ate more — an exploratory result from 11 people at a single meal.

Food Environment & Behavior Metabolic Health News Briefs

Calorie for calorie: what the ultra-processed-diet trial found in 43 men — and the published dispute over what it shows

ultra processed foods green and red labeled plastic pack

A crossover trial matched calories and macronutrients between ultra-processed and unprocessed diets in 43 young men. Fat mass rose about 1 kg on the ultra-processed diet; testosterone and sperm changes were non-significant trends. Two published critiques contest the interpretation.

Food Environment & Behavior Metabolic Health Research Analysis

Why do GLP-1 weight-loss drugs work differently for different people?

Two people can take the same GLP-1 weight-loss drug, follow the same instructions, and get completely different results. Three publications in the same week September 2026 converge on one bottom line: people's responses to these medicines vary widely, and much of that variation — like part of the drugs' heart protection — remains unexplained.

Explainers GLP-1 & Medications Weight Regulation

What Happens When People Stop Weight-Loss Medications

person about to pick medicine from medicine organizer

Pooled evidence from 37 studies and two withdrawal trials: about 0.4 kg regained per month after stopping (0.8 kg after semaglutide or tirzepatide), most lost weight typically returning within about a year, with cardiometabolic gains fading alongside — plus what remains projected, not measured. About 0.4 kg (about 0.9 lb) regained per month after stopping weight-loss medications — 0.8 kg (about 1.8 lb) after semaglutide or tirzepatide — and cardiometabolic gains fade too.

Explainers GLP-1 & Medications Weight Regulation

Testing ultra-processed food and fullness-hormone responses

Burrito, cheese fries, and soda on a tray

A preliminary 14-day controlled feeding trial found that a ~95% ultra-processed diet left GLP-1, PYY, ghrelin and PP responses unchanged in lean young adults — an exploratory, industry-partnership-funded null.

Appetite & Satiety Evidence Watch Food Environment & Behavior

Ultra-processed food and heart risk: what 51 studies show — and where the certainty ends

An anatomical heart model with blue and red vessels on a metal stand

A meta-analysis of 51 cohorts links each extra 100 g/day of ultra-processed food to about 14% higher cardiovascular-event risk. What the low certainty rating and the missed hypertension null mean.

Food Environment & Behavior Metabolic Health Nutrition Research Research Analysis

An 8-hour eating window showed more weight loss — in a group of 11

A preliminary pooled analysis of five time-restricted-eating trials (124 adults) found more weight loss with an 8-hour window — with caveats about subgroup size and statistical adjustment.

Diet Claims & Controversies Evidence Watch Weight Regulation

Three diets, same weight loss: the keto liver-fat trial, read closely

a wooden table topped with bowls of food

A randomized trial of provided meals found keto cut liver fat more at matched ~10% weight loss, while muscle insulin sensitivity rose ~50% in all three diets and LDL/ApoB showed no differences.