Lifestyle advice is important in any obesity treatment modality, but a lifestyle intervention is more than just advice and can be a modality on its own. The value of a lifestyle intervention as a neo-adjuvant treatment in metabolic surgery trajectory has been suggested as an option in a previous guideline.. However, it remained unclear if and when it should be added to the already existing program, typically consisting mainly of lifestyle advice.  New literature on the effectiveness of lifestyle programs surrounding metabolic surgery has emerged, potentially providing more definitive recommendations.

^1. Risk of Bias: serious. Lack of details on possible blinding of outcome assessors and allocation concealment and incorrect blinding of patients in several studies. Frequent of large difference between study groups in loss to follow-up. Imprecision: Serious. Overlap of the 95% CI with the minimal clinically important difference in one of the studies, i.e. boundary of CI includes possibility of benefit or harm and no effect.

^2. Imprecision: Extremely serious. Overlap of the 95% CI with the minimal clinically important difference for several outcomes, i.e. boundary of CI includes possibility of benefit or harm and no effect. Only data from one study per (sub) outcome.

Description of studies

Jassil (2023) performed an RCT in the United Kingdom to investigate the impact of a 12-month adjunctive lifestyle intervention (BARI-LIFESTYLE program) on weight loss and health outcomes after bariatric surgery. Patients were selected from an observational cohort from three National Health Service (NHS) bariatric centers. Patients were included if they were aged 18 to 65 years and planning to undergo either primary gastric bypass or sleeve gastrectomy (SG) surgery (study was initiated before surgery), were medically safe to participate in an exercise program, were able to attend a supervised tailored exercise session weekly for 12 weeks, and were willing to wear a Fitbit and ActiGraph. Patients were excluded from participation if they had a body weight ≥200 kg, were non-ambulatory, had a functional limitation or if they had a medical contraindication for exercise. A total of 143 patients were randomized into a lifestyle intervention group (intervention after surgery) or a standard care group (see Table 2).

Hanvold (2019) performed an RCT in Norway to evaluate the efficacy of a 2-year group-based lifestyle intervention after bariatric surgery (specifically RYGB) compared with usual care on recurrent weight gain and related metabolic risk factors. Patients were included if they underwent RYGB and attended an information meeting on the study. Patients who participated in other studies were excluded. No further inclusion criteria were described. A total of 165 patients were randomized into a lifestyle intervention group or a usual care group (see Table 2).

Lent (2019) performed an RCT in the United States to evaluate the feasibility of a four-month postoperative behavioral intervention program, with a focus on psychosocial outcomes. Patients were included if they were a minimum of 18 years old and completed primary weight-loss surgery within the past 18 months. Patients who underwent surgery revisions, were pregnant or cognitively unable to provide informed consent were excluded. A total of 50 patients were randomized into the intervention group (CBT based) or control group who received usual care (see Table 2). Usual care was not further defined in the study article.

Grilo (2022) performed an RCT in the United States to evaluate the effectiveness of two guided-self-help treatments (CBT-based and based on a lifestyle (LEARN) program) for improving loss of control eating (LOC) after bariatric surgery. Adult patients (aged 18-65 years) with regular LOC-eating (≥once weekly) during the past 28 days were included. Exclusion criteria included use of medication known to effectively influence eating/weight, substance dependence, or severe psychiatric illness requiring acute care. A total of 140 patients were randomized into a CBT intervention group (which did not incorporate physical activity, not further considered for the current analysis), a behavioral weight loss intervention group or a usual care group (see Table 2).

Sockalingham (2023) performed an RCT in Canada to investigate the efficacy of a telephone-based CBT intervention among patients who underwent bariatric surgery. Adult patients (aged 18 years) with a preoperative BMI of ≥40 or a BMI of ≥35 with at least 1 obesity-related comorbidity were included. Exclusion criteria included severe psychiatric illness (psychosis, suicidality). A total of 306 patients were randomized into a tele-CBT intervention group or a usual care group (see Table 2).

Details of the included studies, including details on the intervention and control group, are described in Table 2.

Table 2. Characteristics of included studies

*For further details, see risk of bias table in the appendix

Results

Weight loss

Jassil (2023) reported on weight loss as percentage weight loss at 6-month and 12-month follow-up (post-surgery). Results of 3-month follow-up are also reported but note that the supervised exercise of the intervention was started at three months. At 3 months, only tele-counseling sessions were started in the intervention group. See Table 3 for the results. None of the reported differences between conditions were clinically relevant.

Table 3. Mean weight loss (%) and differences at follow-up between study groups (Jassil, 2023)

Hanvold (2019) reported on weight loss as total weight loss in percentage after two years. The weight loss (SD) in the intervention group was 26.6% (9.8), compared to 27.0% (9.8) in the control group. The corresponding difference is -0.40% (-3.64 to 2.84), which is not clinically relevant. The study did not report results for weight loss after surgery but before the lifestyle intervention.

Hanvold reported also on the difference in total weight loss in both groups between start of the study (after surgery) and at the end of the study (24 months). The difference in weight loss (%) in the intervention group was -3.3% (95%CI: -6.2 to -0.4), compared to -3.1% (95%CI: -5.8 to -0.4) in the control group. These numbers indicate relapse (weight regain); the difference between the two groups is not clinically relevant.

Lent (2019) reported total weight loss in percentage after follow-up (16 months). The weight loss (SD) in the intervention group was 27.2% (7.6), compared to 30.5% (8.1) in the control group. The corresponding difference is 3.30 (95%CI: -1.61 to 8.21), which is not clinically relevant. The study did not report results for weight loss after surgery but before the lifestyle intervention.

Grilo (2022) reported on weight loss as percentage weight loss directly after the intervention, 6-month, 12-month and 24-month follow-up. These results were compared to the total weight at baseline after surgery. See Table 4 for the results. None of the reported differences were clinically relevant .

Table 4. Mean weight loss (%) and differences at follow-up between study groups (Grilo, 2023)

Sockalingham (2023) reported on total weight loss in percentage after follow-up compared to the total weight at baseline after surgery. The total weight loss in the intervention group was 1.08% (0.44), compared to 0.86 (0.42) in the control group. The corresponding difference is 0.22% (CI 95%: 0.12 to 0.32), which is not clinically relevant. The study did not report results for weight loss after surgery but before the lifestyle intervention.

Obesity-related complications

Jassil (2023) reported on obesity-related complications only in term of gastrointestinal adverse events. A total of 7 gastrointestinal events occurred in the intervention group, compared to 2 events in the control group. The number of patients in which these events occurred was not reported. Therefore, these results are not further considered.

• Systolic blood pressure (SBP, mmHg)

Hanvold (2019) reported a SBP (SD) of 127 (6) in the intervention group, compared to 126 (16) in the control group. The corresponding difference is 1.0 (-3.1 to 5.1), which is not clinically relevant.

• Diastolic blood pressure (DBP, mmHg)

Hanvold (2019) reported a DBP (SD) of 80 (11) in the intervention group, compared to 79 (11) in the control group. The corresponding difference is 1.0 (-2.6 to 4.6), which is not clinically relevant.

•Total cholesterol (mmol/L)

Hanvold (2019) reported a total cholesterol (SD) of 4.8 (0.8) in the intervention group, compared to 4.6 (1.0) in the control group. The corresponding difference is 0.2 (-0.1 to 0.5), which is not clinically relevant.

• HbA1c (%) (mmol/L)

Hanvold (2019) reported a HbA1c level (SD) of 5.5 (0.8) in the intervention group, compared to 5.4 (0.8) in the control group. The corresponding difference is 0.10 (-0.2 to 0.4), which is not clinically relevant.

Quality of life

Jassil (2023) reported on quality of life by the EuroQol-5D (EQ-5D) and the Impact of Weight on Quality of Life-Lite (IWQOL-Lite) questionnaires. For the EQ-5D, the index score ranges from -0.448 (worst) to 1.0). For the EQ-5D VAS and the IWQOL-Lite, these scores are o (worst) to 100 (best). Results for questionnaires were reported at 6-month and 12-month follow-up. See Table 4 for the results. None of the reported differences were clinically relevant, except for the results of the EQ-5D index at 6-month follow-up (scores in favor of the control group).

Note: At baseline, the scores differed substantially between the two groups (e.g. EQ-5D: 0.73 and 0.68 for resp. the intervention and control group), resulting in bias.

Table 4. Mean scores and differences between study groups in quality of life, measured by EQ-5D and IWQOL-Lite (Jassil, 2023)

Lent (2019) reported on quality of life by the SF36 after follow-up (16 months). The score ranges from 0 (worst) to 100 (best). For the PHQ-9, the score ranges from 0 (best) to 27 (worst).

The SF36 score in the intervention group was 78.1 (16.3), compared to 66.9 (21.9) in the control group. The corresponding difference is 11.2 (CI 95%: -0.5 to 22.9), which is not clinically relevant.

Psychopathology

Jassil (2023) reported on psychopathology by the Beck Depression Inventory-II (BDI-II). The score ranges from 0 (best) to 63 (worst). Results are also reported in Table 5. None of the reported differences were clinically relevant.

Table 5. Mean scores and differences between study groups in psychopathology, measured by BDI-II (Jassil, 2023)

Lent (2019) reported on psychopathology by the PHQ-9 after follow-up (16 months). The score ranges from 0 (best) to 27 (worst). The PHQ-9 score in the intervention group was 4.9 (4.5), compared to 6.8 (4.9) in the control group. The corresponding difference is -1.9 (CI 95%: -4.80 to 1.0), which is not clinically relevant.

Grilo (2022) reported on the BDI-II. Results are also reported in Table 6. None of the reported differences were clinically relevant.

Table 6. Mean scores and differences between study groups in quality of life, measured by BDI-II (Grilo, 2022)

Sockalingham (2023) reported on psychopathology by PHQ-9 and Generalized Anxiety Disorder 7-item scale (GAD-7). For the GAD-7, the score ranges from 0 (best) to 21 (worst).

The PHQ-9 score in the intervention group was 2.7 (0.3), compared to 4.7 (0.4) in the control group. The corresponding difference is -2.0 (CI 95%: -2.1 to 1.9), which is not clinically relevant.

The GAD-7 score in the intervention group was 2.0 (0.2), compared to 3.5 (0.4) in the control group. The corresponding difference is -1.5 (CI 95%: -1.6 to -1.4), which is not clinically relevant.

• Eating disorder

Grilo (2021/2022) reported on the eating-disorder examination (EDE, global score), which is an interview examination. Results are also reported in Table 7. None of the reported differences were clinically relevant.

Table 7. Mean scores and differences between study groups in eating disorder, measured by EDE global score (Grilo, 2022)

Sockalingham (2023) reported on the Binge Eating Scale (BES). The score ranges from 0 (best) to 46 (worst). The BES score in the intervention group was 6.5 (0.56), compared to 9.1 (0.8) in the control group. The corresponding difference is -2.6 (CI 95%: -2.8 to -2.5), which is considered clinically relevant.

Emotional eating

Lent (2019) reported outcomes of the Loss of control over eating scale-brief (LOCES) and Emotional eating scale (EES, of which the subscale depression is reported here). For the LOCES, the score ranges from 5 (best) to 35 (worst). For the EES-depression, the score ranges from 0 (best) to 36 (worst).

The LOCES score in the intervention group was 11.1 (3.9), compared to 12.4 (4.9) in the control group. The corresponding difference is -1.3 (CI 95%: -4.0 to 1.4), in favor of the intervention group, which is not clinically relevant.

The EES-depression score in the intervention group was 7.1 (4.6), compared to 6.1 (3.9) in the control group. The corresponding difference is 1.0 (CI 95%: -1.69 to 3.69 higher), in favor of the control group, which is not clinically relevant.

A systematic review of the literature was performed to answer the following question:

What is the effectivity of structured lifestyle intervention program (including coaching, with at least a dietary and exercise component) in adult patients with (morbid) obesity who underwent metabolic surgery?

Table 1. PICO

¹Including motivational interviewing, self-monitoring, learning coping strategies, CBT components, stimulus control, behavioral contracts, reward systems, goal-setting techniques, supermarket visits, cooking classes, food diary discussions, strength training, stress management training, mindfulness-based intervention, sleep interventions, emotional eating interventions

Relevant outcome measures

The guideline panel considered weight loss as a critical outcome measure for decision making; and obesity-related complications, quality of life, psychopathology and emotional eating as important outcome measures for decision making.

A priori, the guideline panel did not define the outcome measures listed above but used the definitions used in the studies.

The guideline panel defined the following thresholds as a minimal clinically (patient) important difference: 

• Weight loss: Absolute difference of 5%.
• Obesity-related complications:
  • Systolic blood pressure (SBP): 3 mmHg.
  • Diastolic blood pressure (DBP): 2 mmHg.
  • LDL: 5 mg/dL.
  • HDL: 2 mg/dL.
  • HbA1c: 0.5%.
  • Other complications (inc. triglycerides, total cholesterol): 25% difference (RR <0,75 of >1,25).
• Quality of life (Warkentin, 2014):
  • EuroQoL-5D (EQ-5D) Index: (MCID = 0.03) and EQ-5D Visual Analog Scale (EQ-5D VAS; MCID = 10) (Warkentin, 2014).
  • Impact of Weight on Quality of Life (IWQOL)-Lite total score (MCID = 12)  (Warkentin, 2014).
  • Short Form (SF)-36): Difference of 11.3 point on total score (Longo, 2025).

Psychopathology

• • Beck Depression Inventory (BDI)-II: Difference of 3 points (based on NICE Clinical guideline on Depression, 2004).
  • Patient Health Questionnaire PHQ)-9, with focus on depression: Difference of 3 points (Lynch, 2021).
  • General Anxiety Disorder (GAD)-7: Difference of 4 points (Toussaint, 2020).
  • Eating disorders: 25% difference (RR <0,75 of >1,25) (standard boundaries).
• Emotional eating: 25% difference (RR <0,75 of >1,25) (standard boundaries).

Search and select (Methods)

A systematic literature search was performed by a medical information specialist using the following bibliographic databases: Embase.com and Ovid/Medline. Both databases were searched from 2005 to the 2nd of December 2025 for systematic reviews and RCTs. Systematic searches were completed using a combination of controlled vocabulary/subject headings (e.g., Emtree-terms, MeSH) wherever they were available and natural language keywords. The overall search strategy was derived from the following primary search concepts: (1) metabolic surgery; (2) combined lifestyle intervention. Duplicates were removed using EndNote software. After deduplication and removing of retracted articles a total of 3216 records were imported for title/abstract screening. Titles and abstracts were screened using the ASReview software. The settings ELAS u4 (TF-IDF and SVM) were used. The articles were subsequently screened by the guideline methodologist, using the following stopping rule: stop after 10% of the total set subsequent exclusions (indicating all relevant articles have been screened). Initially, only systematic reviews until 2020 were selected. A total of 39 studies were selected based on title and abstract screening. After reading the full text, 38 studies were excluded (see the exclusion table under the tab ‘Evidence tabellen’).

Note: The search was performed for both preoperative and postoperative lifestyle intervention around metabolic surgery. The results of preoperative lifestyle interventions are described in another chapter.

For the current module on postoperative lifestyle intervention, one systematic review was selected as starting point (Marshall, 2022). This review focused on both preoperative and postoperative intervention. However, none of the included studies could be included in the current literature analysis on postoperative interventions because of the absence of either a dietary or exercise component, a too short intervention period (less than 10 weeks) or a non-randomized design. The literature search for this review (Marshall, 2022) was performed until July 2018.

Additionally, selection was performed for RCT’s published in July 2018 or after (n = 952). This selection was also performed with the ASReview software as described above. Initially, 22 studies were selected based on title and abstract screening. After reading the full text, 17 studies were excluded (see the exclusion table under the tab ‘Evidence Tables) and 5 studies were included. Important study characteristics and results are summarized in Table 2. The assessment of the risk of bias is summarized in the risk of bias tables (under the tab ‘Evidence Tables).

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2. Hanvold SE, Vinknes KJ, Løken EB, Hjartåker A, Klungsøyr O, Birkeland E, Risstad H, Gulseth HL, Refsum H, Aas AM. Does Lifestyle Intervention After Gastric Bypass Surgery Prevent Weight Regain? A Randomized Clinical Trial. Obes Surg. 2019 Nov;29(11):3419-3431. doi: 10.1007/s11695-019-04109-7. PMID: 31363961.
3. Jassil FC, Carnemolla A, Kingett H, Doyle J, Kirk A, Lewis N, Montagut G, Marvasti P, Boniface D, Brown A, Chaiyasoot K, Zakeri R, Mok J, Devalia K, Parmar C, Batterham RL. Impact of nutritional-behavioral and supervised exercise intervention following bariatric surgery: The BARI-LIFESTYLE randomized controlled trial. Obesity (Silver Spring). 2023 Aug;31(8):2031-2042. doi: 10.1002/oby.23814. Epub 2023 Jul 6. PMID: 37415246.
4. Hecker J, Freijer K, Hiligsmann M, Evers SMAA. Burden of disease study of overweight and obesity; the societal impact in terms of cost-of-illness and health-related quality of life. BMC Public Health. 2022 Jan 7;22(1):46. doi: 10.1186/s12889-021-12449-2. PMID: 34996413; PMCID: PMC8740868.
5. Lent MR, Campbell LK, Kelly MC, Lawson JL, Murakami JM, Gorrell S, Wood GC, Yohn MM, Ranck S, Petrick AT, Cunningham K, LaMotte ME, Still CD. The feasibility of a behavioral group intervention after weight-loss surgery: A randomized pilot trial. PLoS One. 2019 Oct 21;14(10):e0223885. doi: 10.1371/journal.pone.0223885. PMID: 31634365; PMCID: PMC6802820.
6. Longo UG, Campi S, De Salvatore S, Piergentili I, Bandini B, Lalli A, Ammendolia V, de Sire A, Papalia R. Minimum clinically important difference of 36-item short form health survey (SF-36) to assess post-surgery quality of life in knee osteoarthritis. J Back Musculoskelet Rehabil. 2025 Jan;38(1):158-164. doi: 10.1177/10538127241296344. Epub 2025 Jan 9. PMID: 39970460.
7. Lynch CP, Cha EDK, Jenkins NW, Parrish JM, Mohan S, Jadczak CN, Geoghegan CE, Singh K. The Minimum Clinically Important Difference for Patient Health Questionnaire-9 in Minimally Invasive Transforaminal Interbody Fusion. Spine (Phila Pa 1976). 2021 May 1;46(9):603-609. doi: 10.1097/BRS.0000000000003853. PMID: 33290370.
8. Marshall S, Mackay H, Matthews C, Maimone IR, Isenring E. Does intensive multidisciplinary intervention for adults who elect bariatric surgery improve post-operative weight loss, co-morbidities, and quality of life? A systematic review and meta-analysis. Obes Rev. 2020 Jul;21(7):e13012. doi: 10.1111/obr.13012. Epub 2020 Mar 20. PMID: 32196906.
9. NCCMH (2004). Depression: Management of Depression in Primary and Secondary Care. British Psychological Society and Royal College of Psychiatrists: Leicester and London
10. Sockalingam S, Leung SE, Ma C, Tomlinson G, Hawa R, Wnuk S, Jackson T, Urbach D, Okrainec A, Brown J, Sandre D, Cassin SE. Efficacy of Telephone-Based Cognitive Behavioral Therapy for Weight Loss, Disordered Eating, and Psychological Distress After Bariatric Surgery: A Randomized Clinical Trial. JAMA Netw Open. 2023 Aug 1;6(8):e2327099. doi: 10.1001/jamanetworkopen.2023.27099. PMID: 37535357; PMCID: PMC10401302.
11. Toussaint A, Hüsing P, Gumz A, Wingenfeld K, Härter M, Schramm E, Löwe B. Sensitivity to change and minimal clinically important difference of the 7-item Generalized Anxiety Disorder Questionnaire (GAD-7). J Affect Disord. 2020 Mar 15;265:395-401. doi: 10.1016/j.jad.2020.01.032. Epub 2020 Jan 15. PMID: 32090765.
12. Warkentin LM, Majumdar SR, Johnson JA, Agborsangaya CB, Rueda-Clausen CF, Sharma AM, Klarenbach SW, Karmali S, Birch DW, Padwal RS. Weight loss required by the severely obese to achieve clinically important differences in health-related quality of life: two-year prospective cohort study. BMC Med. 2014 Oct 15;12:175. doi: 10.1186/s12916-014-0175-5. PMID: 25315502; PMCID: PMC4212133.