The timing of meals affects the processing of fats in the body. A study by the German Center for Diabetes Research (DZD) and the German Institute of Human Nutrition Potsdam-Rehbrücke (DIfE) shows that eating early changes fat metabolism measurably compared to a later time window with the same calorie intake and nutrient composition.

Intermittent fasting, also known as time-restricted eating, is considered a promising strategy for preventing obesity and type 2 diabetes. In this case, food intake is limited to a fixed time window, usually eight hours. Until now, it was unclear whether the time within the day plays a role in fat metabolism.

In the ChronoFast study, a team led by Olga Ramich, Heisenberg Professor at DIfE and Charité – Universitätsmedizin Berlin, investigated this in 31 people who were overweight or obese. In a randomized crossover study, the participants followed two phases: two weeks of eating in the early time window from 8 a.m. to 4 p.m. and two weeks in the late one from 1 p.m. to 9 p.m., in each case with comparable calorie and nutrient intake. Blood samples were taken before and after each phase, and after the interventions, additional samples were taken from the subcutaneous fatty tissue.

Lipidomics analysis of over 300 lipids and lipid-like molecules in the blood plasma showed that significant changes in lipid metabolism occurred only during early eating. The concentration of 103 types of lipids decreased, especially ceramides and phosphatidylcholines, which are linked to type 2 diabetes and cardiovascular disease. The activity of certain enzymes of lipid metabolism also changed significantly.

The timing of meals has an effect on the regulation of fat metabolism, with early eating leading to changes in the lipid profile and enzyme activity in line with circadian rhythms, while eating late does not show this effect.

To clarify the causes, gene activity in adipose tissue was examined. There were marked differences between early and late eating, especially in the glycerophospholipid pathway, which is central to cell membranes and inflammation regulation.

With the metaKEGG tool developed at DIfE, lipidome and transcriptome data were analysed in combination. Three genes were identified, whose activity varied depending on the meal time. These genes encode enzymes that release fatty acids from phospholipids and control remodeling processes in adipose tissue.

The adipose tissue reacts differently to early and late eating, whereby a specific signaling pathway was identified whose involvement in mealtime effects was previously unknown.

The secondary analysis of the ChronoFast study did not reveal any major differences in classical blood parameters such as cholesterol or triglycerides, but at the molecular level, which underlines the potential of lipidomics analyses.

The data opened up new perspectives for chrononutrition in the prevention of obesity and diabetes, as synchronizing the diet with the circadian clock can optimize fat metabolism and prevent metabolic diseases.

The ChronoFast study was conducted at DIfE in cooperation with the Charité, with the participation of Lipotype GmbH Dresden. It was funded by the German Research Foundation, the German Diabetes Society, the European Association for the Study of Diabetes and the DZD.

Lipidomics comprehensively analyzes lipids in biological systems using techniques such as mass spectroscopy to capture diversity, functions, and changes under influences such as diet.

metaKEGG is an open-source software package for the visualization and analysis of molecular signaling pathways across omics levels. In the study, it integrated gene expression and lipidomics data to shed light on effects of time-restricted eating on lipid metabolism and revealed interactions in the glycerophospholipid pathway. It is available at github.com/dife-bioinformatics/metaKEGG and metakegg.apps.dzd-ev.org.

Original Paper:

Impact of Intended Isocaloric Early versus Late Time‐Restricted Eating on Plasma Lipidoma in Women with Overweight or Obesity: Secondary Analysis of the ChronoFast Trial – Szekely – Advanced Science – Wiley Online Library

Editor: X-Press Journalistenbüro GbR

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