Research Center
The evidence behind appetite, hunger, and metabolism
Plain-English summaries of the studies that shape how we understand weight regulation — each with the clinical relevance, practical takeaways, and a link to the original paper. Updated as the science moves.
5 studies summarised · continuously updated
Featured papers
Ultra-processed food made people eat 500 calories a day more: a tightly controlled trial
When meals were matched for calories, sugar, fat, salt and fibre, people still ate ~500 kcal/day more — and gained weight — on the ultra-processed diet.
Hall KD, et al. · Cell Metabolism · 2019
Clinical Trial UpdateSemaglutide and ~15% weight loss: what the STEP 1 trial showed
STEP 1 tested once-weekly semaglutide 2.4 mg in 1,961 adults over 68 weeks. Mean weight loss was about 15%, against roughly 2% on placebo.
Wilding JPH, et al. · New England Journal of Medicine · 2021
Research SummaryThe hunger that doesn't fade: appetite hormones stay changed a year after weight loss
A year after weight loss, hunger hormones hadn't reset: ghrelin stayed high, leptin and PYY low, appetite still elevated — the Sumithran study explained.
Sumithran P, et al. · New England Journal of Medicine · 2011
Latest research
Recently published studies and clinical-trial updates, newest first.
Ultra-processed food made people eat 500 calories a day more: a tightly controlled trial
When meals were matched for calories, sugar, fat, salt and fibre, people still ate ~500 kcal/day more — and gained weight — on the ultra-processed diet.
Hall KD, et al. · Cell Metabolism · 2019
Clinical Trial UpdateTirzepatide and up to ~21% weight loss: the SURMOUNT-1 trial
SURMOUNT-1: a phase 3 trial of 2,539 adults found tirzepatide cut body weight by up to ~21% over 72 weeks, versus ~3% on placebo.
Jastreboff AM, et al. · New England Journal of Medicine · 2022
Clinical Trial UpdateSemaglutide and ~15% weight loss: what the STEP 1 trial showed
STEP 1 tested once-weekly semaglutide 2.4 mg in 1,961 adults over 68 weeks. Mean weight loss was about 15%, against roughly 2% on placebo.
Wilding JPH, et al. · New England Journal of Medicine · 2021
Research SummaryEvery kilo lost makes you ~100 kcal/day hungrier: the appetite feedback that drives regain
A 2016 analysis quantified the hunger that fights weight loss: ~100 kcal/day of extra appetite per kilogram lost, about 3× the metabolic adaptation.
Polidori D, et al. · Obesity · 2016
Research SummaryThe hunger that doesn't fade: appetite hormones stay changed a year after weight loss
A year after weight loss, hunger hormones hadn't reset: ghrelin stayed high, leptin and PYY low, appetite still elevated — the Sumithran study explained.
Sumithran P, et al. · New England Journal of Medicine · 2011
Research collections
What shapes appetite
GLP-1 clinical evidence
- Tirzepatide and up to ~21% weight loss: the SURMOUNT-1 trial · Clinical Trial Update
- Semaglutide and ~15% weight loss: what the STEP 1 trial showed · Clinical Trial Update