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Updated: Jul 11, 2026

Measurement of Basal and Forskolin-stimulated Lipolysis in Inguinal Adipose Fat Pads
Published on: July 21, 2017
Conjugated linoleic acid supplementation alters the 6-mo change in fat oxidation during sleep
Rachel N Close1, Dale A Schoeller, Abigail C Watras
1Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI, USA.
Background:
Conjugated linoleic acid (CLA) is a family of positional and geometric isomers with 2 conjugated double bonds formed from linoleic acid and linolenic acid. CLA has a wide range of biological effects, including body fat reduction.
Objective:
The aim of our study was to determine CLA's effects on energy expenditure, macronutrient utilization, and dietary fat oxidation in overweight adults after 6 mo of supplementation.
Design:
We recruited 23 subjects from our main CLA efficacy study who were receiving either 4 g/d of 78% active CLA isomers (3.2 g/d: 39.2% cis-9,trans-11 and 38.5% trans-10,cis-12) or 4 g/d of safflower oil. Energy expenditure and substrate utilization were measured before and after 6 mo of CLA supplementation by using whole-room indirect calorimetry. Dietary fat oxidation was measured by using stable isotope-labeled oleate and palmitate.
Results:
Our substudy detected a difference in the change in fat utilization between the CLA (4 +/- 8 g) and placebo (-7 +/- 11 g) groups during sleep after 6 mo of supplementation. In addition, the percentage of energy from protein was reduced during sleep in the CLA group (CLA: -3.3 +/- 2.6%; placebo: 0.3 +/- 5.7%). We also detected a difference in the change in energy expenditure during sleep (CLA: 0 +/- 38 kcal; placebo: -43 +/- 90 kcal). We did not detect a change in labeled dietary fat oxidation after 6 mo of CLA supplementation given with a breakfast meal.
Conclusion:
Mixed isomer CLA supplementation, but not placebo, positively altered fat oxidation and energy expenditure during sleep.
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