Overfeeding polyunsaturated fat compared to saturated fat does not differentially influence lean tissue accumulation in overweight individuals: a randomized controlled trial

Fredrik Rosqvist; Jonathan Cedernaes; Andrés Martínez Mora; Michael Fridén; Hans-Erik Johansson; David Iggman; Anders Larsson; Håkan Ahlström; Joel Kullberg; Ulf Risérus

doi:10.1016/j.ajcnut.2024.04.010

Overfeeding polyunsaturated fat compared to saturated fat does not differentially influence lean tissue accumulation in overweight individuals: a randomized controlled trial

Am J Clin Nutr. 2024 Apr 16:S0002-9165(24)00400-3. doi: 10.1016/j.ajcnut.2024.04.010. Online ahead of print.

Authors

Affiliations

¹ Department of Public Health and Caring Sciences, Clinical Nutrition and Metabolism, Uppsala University, Sweden. Electronic address: Fredrik.rosqvist@pubcare.uu.se.
² Department of Medical Sciences, Uppsala University, Sweden; Department of Medical Cell Biology, Uppsala University, Sweden.
³ Department of Surgical Sciences, Radiology, Uppsala University, Sweden.
⁴ Department of Public Health and Caring Sciences, Clinical Nutrition and Metabolism, Uppsala University, Sweden.
⁵ Department of Public Health and Caring Sciences, Clinical Nutrition and Metabolism, Uppsala University, Sweden; Center for Clinical Research Dalarna, Uppsala University, Sweden.
⁶ Department of Medical Sciences, Clinical Chemistry, Uppsala University, Sweden.
⁷ Department of Surgical Sciences, Radiology, Uppsala University, Sweden; Antaros Medical AB, Mölndal, Sweden.

PMID: 38636844
DOI: 10.1016/j.ajcnut.2024.04.010

Abstract

Background: Fatty acids may influence lean tissue volume and skeletal muscle function. We previously reported in young lean participants that overfeeding polyunsaturated fat (PUFA) compared with saturated fat (SFA) induced greater lean tissue accumulation despite similar weight gain.

Objective: In a double-blind randomized controlled trial (RCT), we aimed to investigate if the differential effects of overfeeding SFA and PUFA on lean tissue accumulation could be replicated in individuals with overweight, and identify potential determinants. Further, using substitution models, we investigated associations between SFA and PUFA levels with lean tissue volume, in a large population-based sample (UK Biobank).

Methods: Sixty-one males and females with overweight (BMI 27.3 (interquartile range 25.4 to 29.3), age 43 (interquartile range 36 to 48)) were overfed SFA (palm oil) or n-6 PUFA (sunflower oil) for 8 weeks. Lean tissue was assessed by magnetic resonance imaging (MRI). We had access to n=13849 participants with data on diet, covariates and MRI measurements of lean tissue, as well as 9119 participants with data on circulating fatty acids, in the UK Biobank.

Results: Body weight gain (mean±SD) was similar in PUFA (2.01±1.90 kg) and SFA (2.31±1.38 kg) groups. Lean tissue increased to a similar extent (0.54±0.93 L and 0.67±1.21 L for PUFA and SFA group, respectively, with a difference between groups of 0.07 (-0,21, 0,35)). We observed no differential effects on circulating amino acids, myostatin or interleukin-15 and no clear determinants of lean tissue accumulation. Similar non-significant results for SFA and PUFA were observed in UK Biobank, but circulating fatty acids demonstrated ambiguous and sex-dependent associations.

Conclusion: Overfeeding SFA or PUFA does not differentially affect lean tissue accumulation during 8 weeks in individuals with overweight. A lack of dietary fat type-specific effects on lean tissue is supported by specified substitution models in a large population-based cohort consuming their habitual diet.

Trial registration: ClinicalTrials.gov Identifier: NCT02211612.

Keywords: Saturated fat; body composition; lean tissue; overfeeding; polyunsaturated fat.

Associated data

ClinicalTrials.gov/NCT02211612