Metabolic Inflexibility in Youth With Obesity: Is It a Feature of Obesity or Distinctive of Youth Who Are Metabolically Unhealthy?

Authors

Nour Y Gebara
Joon Young Kim
Fida Bacha
SoJung Lee
Silva Arslanian

Publication Date

4-1-2022

Journal

Clinical Obesity

DOI

10.1111/cob.12501

PMID

34851557

PMCID

PMC8904284

PubMedCentral® Posted Date

4-1-2023

PubMedCentral® Full Text Version

Author MSS

Published Open-Access

yes

Keywords

Adipose Tissue, Adolescent, Humans, Insulin, Insulin Resistance, Metabolic Syndrome, Obesity, Obesity, Metabolically Benign, Metabolic flexibility, Metabolic Health, Obesity, Insulin Sensitivity

Abstract

Background:

Individuals with obesity have metabolic inflexibility with diminished fasting fat oxidation and blunted increase in respiratory quotient (RQ) in insulin-stimulated states. However, it is unclear if metabolic inflexibility is a characteristic of obesity per se or is unique to youth who have metabolically unhealthy obesity (MUO) compared with metabolically healthy obesity (MHO).

Objective:

We investigated metabolic flexibility in youth with MUO, MHO and normal weight (NW) and compared their metabolic characteristics.

Patients/Design:

Youth (n=188) were divided, based on cut-off points for in vivo insulin sensitivity (IS) of adolescents with NW, into 137 with MUO and 51 with MHO. Fasting hepatic IS (HIS) from hepatic glucose production by [6,6-²H₂]glucose, adipose tissue IS (ATIS) from whole-body lipolysis by [²H₅]glycerol, RQ (indirect calorimetry) during fasting and a hyperinsulinemic (80mu/m²/min)-euglycemic clamp were measured.

Results:

Youth with MUO vs. MHO had blunted ΔRQ (p=0.035) and lower HIS and ATIS (both p<0.0001), while ΔRQ, HIS and ATIS were not different between youth with MHO and NW. In a pair-matched sub-analyses of 30 MUO and 30 MHO the results were similar to the total cohort.

Conclusions:

Metabolic inflexibility, does not appear to be a feature of obesity per se rather distinctive of youth with MUO, who also have worse HIS and ATIS compared with youth with MHO.