Does taste preference predict weight regain after bariatric surgery?

Changes in Food Preferences Before and After Intragastric Balloon Placement

BACKGROUNDS

In recent years, numerous studies have tried to decode the way bariatric surgery works toward weight reduction by the use of food preference questionnaires. The intragastric balloon has gained popularity, mainly due to its limited invasiveness, in patients with obesity not fulfilling criteria for bariatric surgery. However, there is no study assessing the changes in food preferences [FP]. We decided to analyze the FP of individuals prior to intragastric balloon insertion and following its removal, on the strict condition that participants must complete the 6-month treatment period and attend at least 4 of the 7 follow-up interviews.

METHODS

Patients were asked to rate the frequency of consumption of 63 food items before balloon insertion, at monthly intervals and after balloon removal. The food categories were protein, carbohydrates, fruit and vegetables, and sweets and fats.

RESULTS

The questionnaires of 320 participants were analyzed. A reduced frequency in consumption of meat and meat products, high-fat, and high-carbohydrate/sugary products and an increase in raw vegetables and fruit was found in all individuals.

CONCLUSION

The intragastric balloon seems to exert analogically similar mechanisms to bariatric surgery for weight loss, both functioning through alterations in FP. These are dictated by the anatomical re-configuration of the stomach, but mainly by counseling of dieticians and the self-education of the patient after experiencing unpleasant postprandial discomfort.

Changes in appetite, taste, smell, and food aversion in post-bariatric patients and their relations with surgery time, weight loss and regain

PURPOSE

We aimed to study the occurrence of long-term changes in appetite, taste, smell perceptions, and food aversion in patients following bariatric surgery. Additionally, we compared two surgery types, excess weight loss, rate of weight regain, and time since surgery.

METHODS

This cross-sectional study included 146 post-bariatric patients who were without regular medical follow-up (126 post-Roux-en-Y gastric bypass [RYGB] and 20 post-sleeve gastrectomy [SG]), aged 42 ± 8 years, BMI of 32.6 ± 6.3 kg/m², with excess weight loss of 87.5 ± 20.2%, rate of weight regain (RWR) of 15.4 [3.9-30.9]% and time since surgery of 5.0 ± 4.0 years. They answered a questionnaire about sensory and food perceptions at their first medical appointment at our unit.

RESULTS

Changes in appetite (76%), taste (48.6%), and an increased sensation for sweet taste (60.2%) frequently occurred in our sample. Sensory and food aversion perceptions, taste changes to specific foods, and loss level of taste and smell were similar between RYGB and SG. No differences between patients with or without changes in appetite, taste, smell, and food aversion perceptions concerning excess weight loss were observed. The RWR in post-RYGB was lower in those with changes in taste and smell (P = 0.05). Sensory changes were noted in those with shorter time since surgery for both surgeries (P ≤ 0.05).

CONCLUSION

Changes in appetite and taste occurred frequently in our patients even in the long term. Post-RYGB patients with lower RWR had more changes in taste and smell while a shorter time since surgery showed more frequent changes in appetite, taste, and smell.

LEVEL OF EVIDENCE

Level V, cross-sectional study.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (NCT04193384).

Preoperative brain μ-opioid receptor availability predicts weight development following bariatric surgery in women

Bariatric surgery is the most effective method for weight loss in morbid obesity. There is significant individual variability in the weight loss outcomes, yet factors leading to postoperative weight loss or weight regain remain elusive. Alterations in the μ-opioid receptor (MOR) and dopamine D₂ receptor (D₂R) systems are associated with obesity and appetite control, and the magnitude of initial brain receptor system perturbation may predict long-term surgical weight loss outcomes. We tested this hypothesis by studying 19 morbidly obese women (mean BMI 40) scheduled to undergo bariatric surgery. We measured their preoperative MOR and D₂R availabilities using positron emission tomography with [¹¹C]carfentanil and [¹¹C]raclopride, respectively, and then assessed their weight development association with regional MOR and D₂R availabilities at 24-month follow-up. MOR availability in the amygdala consistently predicted weight development throughout the follow-up period, but no associations were found for D₂R. This is the first study to our knowledge to demonstrate that neuroreceptor markers prior to bariatric surgery are associated with postoperative weight development. Postoperative weight regain may derive from dysfunction in the opioid system, and weight loss outcomes after bariatric surgery may be partially predicted based on preoperative brain receptor availability, opening up new potential for treatment possibilities.

Factors Related to Weight Loss Maintenance in the Medium-Long Term after Bariatric Surgery: A Review

Despite bariatric surgery being the most effective treatment for obesity, some individuals do not respond adequately, especially in the long term. Identifying the predictors of correct weight maintenance in the medium (from 1 to 3 years after surgery) and long term (from 3 years and above) is of vital importance to reduce failure after bariatric surgery; therefore, we summarize the evidence about certain factors, among which we highlight surgical technique, psychological factors, physical activity, adherence to diet, gastrointestinal hormones or neurological factors related to appetite control. We conducted a search in PubMed focused on the last five years (2015–2021). Main findings are as follows: despite Roux-en-Y gastric bypass being more effective in the long term, sleeve gastrectomy shows a more beneficial effectiveness–complications balance; pre-surgical psychological and behavioral evaluation along with post-surgical treatment improve long-term surgical outcomes; physical activity programs after bariatric surgery, in addition to continuous and comprehensive care interventions regarding diet habits, improve weight loss maintenance, but it is necessary to improve adherence; the impact of bariatric surgery on the gut–brain axis seems to influence weight maintenance. In conclusion, although interesting findings exist, the evidence is contradictory in some places, and long-term clinical trials are necessary to draw more robust conclusions.