Clinical Report: Impact of Sleeve Gastrectomy on Taste Perception via Progressive Ratio Task

Overview

This study assessed appetitive behavior in adolescents undergoing sleeve gastrectomy (SG) using the progressive ratio task (PRT) pre-surgery, and at 1 and 6 years post-operation. Results indicate changes in motivation to obtain a palatable food reward post-SG, reflecting alterations in taste perception and reward processing over time.

Background

Obesity is a chronic disease characterized by increased appetitive behavior and excessive food intake. Sleeve gastrectomy is an effective treatment for obesity in adolescents, leading to sustained weight loss and resolution of complications. Food intake is influenced by sensory, reward, and physiological domains of taste, with palatability impacting food reward. Changes in peripheral and central gustatory systems and brain reward circuits contribute to weight loss after SG. The progressive ratio task is a validated method to assess appetitive reward motivation in humans and animals.

Data Highlights

The study included adolescents eligible for SG (BMI ≥40 kg/m2 or ≥35 kg/m2 with complications) and a comparator group without weight loss interventions. The PRT involved progressively increasing effort (button presses) to obtain a low-calorie chocolate candy reward, measuring breakpoint as an indicator of reward value. Participants were tested pre-surgery, and at 1 and 6 years post-SG. Hunger, fullness, desire to eat, and nausea were assessed via visual analogue scales before and after the task. Statistical analyses included Mann-Whitney, Wilcoxon, ANOVA, and Spearman correlations.

Key Findings

• Adolescents undergoing SG showed altered appetitive behavior as measured by the progressive ratio task at 1 and 6 years post-surgery compared to pre-surgery.
• The breakpoint, reflecting motivation to obtain a palatable food reward, decreased after SG, indicating reduced reward value of calorie-dense foods.
• Changes in taste perception and reward processing post-SG likely contribute to reduced food intake and sustained weight loss.
• The comparator group without surgery did not show significant changes in appetitive behavior over time.
• Low-calorie reinforcers minimized postingestive feedback, isolating the sensory and reward components of taste in the assessment.

Clinical Implications

These findings suggest that sleeve gastrectomy induces long-term changes in taste perception and reward-driven appetitive behavior, which may support sustained reductions in calorie intake. Clinicians should consider the impact of altered taste reward processing when counseling patients post-SG. The progressive ratio task may serve as a useful tool to objectively assess changes in food reward motivation following bariatric surgery.

Conclusion

Sleeve gastrectomy in adolescents leads to decreased motivation to obtain palatable, calorie-dense foods as measured by the progressive ratio task, reflecting altered taste perception and reward mechanisms that contribute to long-term weight loss. These behavioral changes persist up to six years post-surgery.

References

1. Obesity and Sleeve Gastrectomy References [1-6]
2. Taste and Reward Mechanisms in Food Intake [7-9]
3. Progressive Ratio Task and Bariatric Surgery Studies [14,17-19]