CALERIE abstract: 2-year calorie restriction and time-dependent metabolomic shifts
In the CALERIE abstract, healthy adults without obesity randomized to 2 years of calorie restriction or ad libitum eating showed different time patterns in carbohydrate, lipid and partially characterized plasma metabolites. These are associations from an abstract, not proven causes or lifespan benefits. [1]
Automatic summary · not editorially reviewed
The key findings
Healthy adults without obesity were randomized to 2 years of calorie restriction or an ad libitum control, with fasted plasma sampled at baseline, 12 and 24 months. [1]
Carbohydrate (PC2) and partially characterized metabolites (PC5) fell from baseline to 12 months in both groups, then diverged from 12 to 24 months. [1]
The authors say further work is needed to separate CR-specific adaptations from dietary influences and to clarify the functional significance for aging. [1]
The source at a glance
- Study type / format
- Randomized trial abstract with untargeted metabolomics.
- Population / context
- Healthy adults without obesity participating in the CALERIE trial.
- Summary based on
- Study abstract
- Publication status
- Preprint · peer-review status not confirmed
- Original publication
- March 30, 2026
CALERIE adults without obesity: randomized CR versus ad libitum
The abstract describes a study in healthy adults without obesity. Participants were randomized to 2 years of calorie restriction (CR) or an ad libitum (AL) control, meaning eating without prescribed restriction. Fasted plasma samples were collected at baseline, 12 and 24 months. Untargeted metabolomics identified 864 known metabolites, grouped into nine super pathways, including amino acid, carbohydrate, energy, lipid and nucleotide categories. Principal component analysis summarized variation, and linear mixed models tested group-by-time interactions. The abstract does not report sample size, dropouts or the size of the effects.
Supporting source [1]
Three metabolite components differed by group over time
Three principal components showed significant group-by-time interactions: PC2 (carbohydrate), PC5 (partially characterized molecules) and PC4 (lipid). From baseline to 12 months, carbohydrate (PC2) and partially characterized metabolites (PC5) decreased in both groups. From 12 to 24 months, PC2 stabilized in CR but increased in AL, while PC5 continued to decline in AL and increased in CR. Lipid metabolites (PC4) decreased in CR and increased in AL at 12 months, with the pattern reversing from 12 to 24 months. Key contributors were malto-saccharides and related carbohydrate intermediates for PC2, glutamine degradants and lactone sulfates for PC5, and sphingolipids for PC4.
Supporting source [1]
Abstract-only scope: adaptations not yet separated from diet
The authors interpret the shifts as time-dependent changes in carbohydrate and lipid metabolism, with early reductions during the weight-loss phase followed by stabilization or compensatory responses during weight maintenance. They suggest these changes may relate to inflammation-linked mechanisms. They state that further work is needed to distinguish CR-specific adaptations from dietary influences and to clarify what these metabolic responses mean for aging and long-term metabolic health. The abstract does not establish that CR extends human lifespan or causes health benefits; the full text was not reviewed.
Supporting source [1]
How to interpret this
This is an abstract only; the full text was not reviewed. Sample size, dropouts, effect sizes and adverse events are not reported. The metabolite patterns are associations, not proven causes, and no human lifespan or health benefit is established.
Based on the study abstract; the full paper, tables and supplementary data were not reviewed.
Source & supporting passages
Orenduff MC, Woolf EK, Zhang R, Belsky DW, Das SK, Hastings W, Mucinski JM, Racette SB, Redman LM, Waziry R, Kraus WE, Pieper CF, Huffman KM. · europepmc.org · March 30, 2026