Metabolic and Orexin-A Responses to Ketogenic Diet and Intermittent Fasting: A 12-Month Randomized Trial in Adults with Obesity.

What Was Tested

The paper reports a study of Orexin-A, published as a randomized controlled trial.

However, their long-term neuroendocrine effects-particularly those involving Orexin-A, a peptide implicated in energy regulation-remain poorly understood.

The objective of this study was to compare the long-term metabolic, inflammatory, and orexinergic responses to different dietary strategies in adults with obesity.

Who Took Part

The abstract describes 30 adults taking part.

The age groups tagged for this paper are adults and middle-aged adults, both men and women.

In this 12-month randomized, three-arm trial, 30 adults with obesity (BMI ≥ 30 kg/m2) were randomly assigned (1:1:1) to a hypocaloric ketogenic diet (KD), a 16:8 time-restricted eating regimen (TRF16:8), or a 5:2 intermittent fasting protocol (ADF5:2).

How the Study Was Run

The researchers set it up as a randomized study.

The adults were allocated by chance, so the Orexin-A group and the comparison group should start out alike.

Anthropometric parameters, body composition, fasting glucose, lipid profile, inflammatory cytokines (CRP, IL-6, TNF-α, IL-10), and plasma Orexin-A levels were assessed at baseline and every 3 months.

Statistical analyses included repeated-measures models with sensitivity analyses adjusted for age and sex.

What Was Measured

Topics PubMed links to this paper include Diet, Ketogenic, Orexins, Obesity, Fasting, Blood Glucose, Body Mass Index and Body Composition.

The authors tagged it with the keywords Orexin-A, intermittent fasting, ketogenic diet, metabolic flexibility and obesity management.

What This Means in Plain Language

The paper is a randomized study of Orexin-A in 30 adults.

With fewer than 40 people, it is a small study, so it is better read as an early signal for further research than as a settled answer.

Results are reported in around 9 sentences of the abstract; we leave them to the paper itself rather than summarise them.

The publication is from 2026 (Nutrients), a journal based in Switzerland.

More context: the Orexin-A compound page, all human trials.