The Relationship Between Olfactory and Gustatory Senses, Hedonic Hunger, and Diet Quality After Bariatric Surgery

Hanife Köksal

Status: Completed

Conditions: Smell Disorder; Obesity; Taste Disorders

Treatments: Other: Sleeve Gastrectomy (SG) and Roux-en-Y Gastric Bypass (RYGB)

Study type: Observational

Funder types: Other

Identifiers

NCT07290075

USK-NUTR-HK01

Details and patient eligibility

About

This cross-sectional observational study investigates the association between changes in olfactory and gustatory senses and hedonic hunger among individuals who have undergone bariatric surgery. The study also examines the effects of these sensory changes on diet quality and anthropometric measurements. Participants completed a structured questionnaire including sociodemographic and health information, dietary habits, a modified 33-item taste and smell assessment, the Power of Food Scale (PFS), the Mediterranean Diet Adherence Screener (MEDAS), the International Physical Activity Questionnaire (IPAQ), and anthropometric measurements.

Full description

Obesity is a chronic, multifactorial disease that negatively impacts health and quality of life. Bariatric surgery is an effective treatment option for severe obesity, leading to significant and sustained weight loss as well as improvement in obesity-related comorbidities.

Postoperative changes in taste and smell perception are frequently reported by bariatric patients and may influence food preferences, hedonic hunger, and overall diet quality. These sensory alterations can result from anatomical and hormonal changes after surgery, including altered gut hormone secretion (e.g., PYY, GLP-1, ghrelin) and bile acid metabolism, which affect appetite regulation and reward pathways.

This cross-sectional observational study evaluated adults aged 18-65 years who had undergone sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) at least three months prior to enrollment. Data collection included sociodemographic and health information, dietary habits, a modified 33-item taste and smell questionnaire, the Power of Food Scale (PFS) to assess hedonic hunger, the Mediterranean Diet Adherence Screener (MEDAS), the International Physical Activity Questionnaire (IPAQ), and anthropometric measurements. Nutrient intakes were analyzed according to the Türkiye Nutrition Guide (TÜBER-2022) reference values.

The primary objective was to determine the relationship between postoperative taste/smell changes and hedonic hunger. Secondary objectives included assessing the association between sensory perception and Mediterranean diet adherence, anthropometric parameters, and nutrient adequacy by surgery type. Findings from this study may guide the development of personalized nutritional follow-up protocols to improve long-term outcomes in bariatric patients.

Enrollment: 101 patients

Sex: All

Ages: 18 to 65 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Adults aged 18 to 65 years
• History of bariatric surgery (Sleeve Gastrectomy or Roux-en-Y Gastric Bypass)
• At least 3 months post-surgery at the time of study enrollment
• Able and willing to provide informed consent

Exclusion criteria

• Pregnancy
• History of neurological disorders affecting taste or smell
• Active upper respiratory infection at the time of assessment
• Severe psychiatric disorders that may impair participation

Trial design

101 participants in 2 patient groups

Sleeve Gastrectomy (SG)

Description:

Participants who underwent sleeve gastrectomy at least 3 months prior to enrollment.

Treatment:

Other: Sleeve Gastrectomy (SG) and Roux-en-Y Gastric Bypass (RYGB)

Roux-en-Y Gastric Bypass (RYGB)

Description:

Participants who underwent Roux-en-Y gastric bypass at least 3 months prior to enrollment.

Treatment:

Other: Sleeve Gastrectomy (SG) and Roux-en-Y Gastric Bypass (RYGB)