Obesity is associated with increased morbidity and mortality due to cardiometabolic disease, cancer, and mental disorders.^1,2 Current treatment options for severe obesity encompass medical therapy and bariatric surgery.³ Intensive lifestyle intervention is associated with 5% to 8% weight loss and improvement of cardiovascular risk factors,^4,5 while bariatric surgery is associated with larger weight loss and medium- to long-term (1- to 5-year) remission of hypertension, type 2 diabetes, and dyslipidemia.^6-9 Bariatric surgery is associated with a number of somatic and mental complications, but few studies report long-term complication rates.^6,10

Journal of Medical Internet Research - International Scientific Journal for Medical Research, Information and Communication on the Internet #Preprint #PeerReviewMe: Warning: This is a unreviewed preprint. Readers are warned that the document has not been peer-reviewed by expert/patient reviewers or an academic editor, may contain misleading claims, and is likely to undergo changes before final publication, if accepted, or may have been rejected/withdrawn. Readers with interest and expertise are encouraged to sign up as peer-reviewer, if the paper is within an open peer-review period. Please cite this preprint only for review purposes or for grant applications and CVs (if you are the author). Background: Maintaining weight after weight loss is a major health challenge, and eHealth solutions may be one way to meet this challenge. Application of behavior change techniques (BCTs) and persuasive system design (PSD) principles in eHealth development may contribute to design of technologies that positively influence behavior and motivation to support the sustainable health behavior change needed. Objective: To identify BCTs and PSD principles stimulating motivation and adherence in eHealth interventions supporting weight maintenance following weight loss. Methods: A systematic literature search was performed in the databases: PsycInfo, Ovid Medline, Embase, Scopus, Web of Science, and Amed, from January 1, 2007 to June 30, 2018. Arksey and O’Malley scoping review methodology was applied, using Michie´s Behavior Change Taxonomy and the Persuasive System Design-model to identify techniques and principles used. Publications on eHealth interventions were included if focused on weight loss or weight loss maintenance, in combination with motivation or adherence and behavior change. The main focus of this review was on weight loss maintenance. However, eHealth interventions targeting weight loss were also examined, particularly for weight loss maintenance related factors. Results: The search identified 317 publications, of which 45 met the inclusion criteria. Eleven focused on weight loss maintenance and 34 on weight loss. Smartphone (n=28) was the most frequently used technology. Frequently used wearables or sensors were activity trackers or step-counters (n=14), as well as other monitoring technologies such as wireless or digital scales (n=8). Several interventions had a human support component in a blended care format (n=27). Feedback and monitoring and goals and planning were core BCT clusters applied in the majority of included publications. Social support and associations through prompts and cues to support and maintain new habits were more frequently used in weight loss maintenance than weight loss interventions. In both types of interventions, frequently applied PSD principles were self-monitoring, goal-setting and feedback. Tailoring, reminders, personalization and rewards were additional principles frequently applied in weight loss maintenance interventions. Results did not reveal an “ideal” combination of BCTs or PSD principles to stimulate motivation, adherence and weight loss maintenance. The most frequently mentioned individual BCTs and PSD principles applied to stimulate motivation were however personalization, praise and feedback, while associations were frequently mentioned to stimulate adherence. eHealth interventions that found significant effects for weight loss maintenance all applied self-monitoring, feedback, goal-setting, and shaping knowledge, combined with a human social support component. Conclusions: To our knowledge, this is the first review examining key BCTs and PSD principles applied in weight loss maintenance interventions compared with those of weight loss interventions. The most successful eHealth weight loss maintenance interventions entailed a combination of BCTs and PSD principles, including tailoring, self-monitoring, feedback, goals and planning, and shaping knowledge to support creation and establishment of healthy habits and behaviors. The current review identified several techniques and principles applied to stimulate motivation and adherence. Future research should however aim to examine which eHealth design combinations can be the most effective in support of long-term behavior change and weight loss maintenance.

Background: An increasing number of eHealth interventions aim to support healthy behaviors that facilitate weight loss. However, there is limited evidence of the effectiveness of the interventions and little focus on weight loss maintenance. Knowledge about end user values and needs is essential to create meaningful and effective eHealth interventions, and to identify persuasive system design (PSD) principles and behavior change techniques (BCTs) that may contribute to the behavior change required for successful long-term weight loss maintenance. Objective: This study aimed to provide insight into the design of eHealth interventions supporting behavior change for long-term weight maintenance. The study sought to identify the values and needs of people with obesity aiming to maintain weight after weight loss, and to identify PSD principles, BCTs, and design requirements that potentially enable an eHealth intervention to meet end user values and needs. Methods: This study presents the concept of integrating PSD principles and BCTs into the design process of eHealth interventions to meet user values and needs. In this study, individual interviews and focus groups were conducted with people with obesity (n=23) and other key stakeholders (n=27) to explore end user values and needs related to weight loss maintenance. Design thinking methods were applied during the focus group sessions to identify design elements and to explore how eHealth solutions can support the needs to achieve sustainable weight loss maintenance. The PSD model and behavior change taxonomy by Michie were used to identify PSD principles and BCT clusters to meet end user values and needs. Results: A total of 8 key end user values were identified, reflecting user needs for weight loss maintenance support: self-management, personalized care, autonomy, feel supported, positive self-image, motivation, happiness, and health. Goals and planning, feedback and monitoring, repetition and substitution, shaping knowledge, social support, identity, and self-belief were some of the BCT clusters identified to address these concepts, together with PSD principles such as personalization, tailoring, self-monitoring, praise, and suggestions. Conclusions: The process of translating end user values and needs into design elements or features of eHealth technologies is an important part of the design process. To our knowledge, this is the first study to explore how PSD principles and BCTs can be integrated when designing eHealth self-management interventions for long-term weight loss maintenance. End users and other key stakeholders highlighted important factors to be considered in the design of eHealth interventions supporting sustained behavior change. The PSD principles and BCTs identified provide insights and suggestions about design elements and features to include for supporting weight loss maintenance. The findings indicate that a combination of BCTs and PSD principles may be needed in evidence-based eHealth interventions to stimulate motivation and adherence to support healthy behaviors and sustained weight loss maintenance. Trial Registration: ClinicalTrials.gov NCT04537988; https://clinicaltrials.gov/ct2/show/NCT04537988

Objective: This study aimed to compare the effects of two aerobic exercise programs of different intensities on energy expenditure.Methods: This was a single‐center randomized controlled trial of patients with severe obesity allocated to a 24‐week moderate‐intensity continuous training (MICT) program or a combined MICT with high‐intensity interval training (HIIT/MICT) program. The primary outcome was energy expenditure during exercise (EEDE). Secondary outcomes included resting metabolic rate, cardiorespiratory fitness, and body composition.Results: A total of 82 (56% females) patients were screened, and 71 (55% females) patients were allocated to HIIT/MICT (n = 37) or MICT (n = 34). Per‐protocol analysis showed that EEDE increased by 10% (95% CI: 3%‐17%) in the HIIT/MICT group (n = 16) and 7.5% (95% CI: 4%‐10%) in the MICT group (n = 24), with no differences between groups. In the 8‐ to 16‐ week per‐protocol analysis, the HIIT/MICT group had a significantly larger increase in EEDE compared with the MICT group. Resting metabolic rate remained unchanged in both groups. HIIT/MICT and MICT were associated with significant weight loss of 5 kg and 2 kg, respectively.Conclusions: Patients completing a 24‐week combined HIIT/MICT program did not achieve a higher EEDE compared with those who completed a 24‐week MICT program. The HIIT/MICT group experienced, on average, a 3‐kg‐larger weight loss than the MICT group.

Obesity is associated with increased risk of cardiovascular disease. Arterial stiffness assessed by carotid femoral pulse wave velocity (PWV) is an independent predictor of cardiovascular morbidity and mortality. We aimed to investigate how various measures of body composition affect arterial stiffness.