Effect of obesity surgery on taste, brain function and structure
File(s)
Author(s)
Al Alsheikh, Alhanouf
Type
Thesis
Abstract
Background:
Obesity is a global health concern with complex underlying mechanisms. Understanding eating behaviour is key to addressing obesity, as it influences both its development and treatment. Bariatric surgery offers an effective, long-term solution, leading to significant metabolic improvements. Recent advances in neuroimaging have enabled investigation of the neural correlates of eating behaviour in obesity, particularly the brain’s reward systems.
Aims:
This thesis explores the impact of obesity surgery on taste, brain metabolism, and brain structure through three systematic reviews:
1. Taste function: Does obesity surgery alter taste function in humans with obesity?
2. Brain metabolism (PET/SPECT studies): How does obesity surgery or dietary intervention affect brain metabolism and neurotransmitters? How do these changes differ between interventions, and what do they reveal about obesity-related brain disturbances?
3. Brain structure (MRI studies): Does obesity surgery alter brain structure, and how does this compare to dietary interventions?
Methods:
Systematic searches were conducted across PubMed, Web of Science, PsycINFO, MEDLINE, and EMBASE. Inclusion/exclusion criteria were defined, and detailed data extraction focused on study quality, participant characteristics, interventions, brain outcomes, and potential mediators such as gut hormones and eating behaviour. Meta-analyses were performed where appropriate.
Results:
Taste detection improves post-surgery, with reduced appetitive response to sweet tastes. PET/SPECT studies show increased MOR binding and decreased brain glucose uptake after surgery and diet, suggesting weight loss normalises obesity-related brain alterations. Structural MRI data indicate limited changes in cortical and subcortical brain volumes post-surgery.
Conclusion:
Obesity surgery induces complex changes in taste, brain function, and structure, yet studies face limitations including small sample sizes and methodological variability. Larger, multicentre studies using advanced PET/MRI protocols, diverse nutritional states, and robust statistical approaches are needed to clarify how brain changes influence eating behaviour and weight loss outcomes.
Obesity is a global health concern with complex underlying mechanisms. Understanding eating behaviour is key to addressing obesity, as it influences both its development and treatment. Bariatric surgery offers an effective, long-term solution, leading to significant metabolic improvements. Recent advances in neuroimaging have enabled investigation of the neural correlates of eating behaviour in obesity, particularly the brain’s reward systems.
Aims:
This thesis explores the impact of obesity surgery on taste, brain metabolism, and brain structure through three systematic reviews:
1. Taste function: Does obesity surgery alter taste function in humans with obesity?
2. Brain metabolism (PET/SPECT studies): How does obesity surgery or dietary intervention affect brain metabolism and neurotransmitters? How do these changes differ between interventions, and what do they reveal about obesity-related brain disturbances?
3. Brain structure (MRI studies): Does obesity surgery alter brain structure, and how does this compare to dietary interventions?
Methods:
Systematic searches were conducted across PubMed, Web of Science, PsycINFO, MEDLINE, and EMBASE. Inclusion/exclusion criteria were defined, and detailed data extraction focused on study quality, participant characteristics, interventions, brain outcomes, and potential mediators such as gut hormones and eating behaviour. Meta-analyses were performed where appropriate.
Results:
Taste detection improves post-surgery, with reduced appetitive response to sweet tastes. PET/SPECT studies show increased MOR binding and decreased brain glucose uptake after surgery and diet, suggesting weight loss normalises obesity-related brain alterations. Structural MRI data indicate limited changes in cortical and subcortical brain volumes post-surgery.
Conclusion:
Obesity surgery induces complex changes in taste, brain function, and structure, yet studies face limitations including small sample sizes and methodological variability. Larger, multicentre studies using advanced PET/MRI protocols, diverse nutritional states, and robust statistical approaches are needed to clarify how brain changes influence eating behaviour and weight loss outcomes.
Version
Open Access
Date Issued
2024-07-05
Date Awarded
2025-06-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
Miras, Alexander
Goldstone, Tony
Publisher Department
Department of Metabolism, Digestion and Reproduction
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)