Behavioral Factors Associated With ≥ 15% Versus < 5% Weight Loss in Adults With Severe Obesity: A Retrospective Clinical Study

ABSTRACT

Background

Sustained weight loss requires a persistent reduction in energy intake combined with increased energy expenditure. Assessment of such strategies can improve treatment outcomes. The National Weight Control Registry (NWCR) has identified behavioral approaches associated with successful long‐term weight loss maintenance.

Objectives

To assess the prevalence of self‐reported NWCR strategies and examine their association with achieving ≥ 15% versus < 5% weight loss (WL) within a structured obesity treatment program.

Methods

Adults with a BMI ≥ 35 kg/m² at program initiation were included. Electronic medical records were retrospectively reviewed at baseline and at 6 and 12 months. Assessed NWCR strategies included reduced energy intake, reduced fat and sugar consumption, regular breakfast consumption, consistent meal frequency, self‐weighing, food intake monitoring, and regular physical activity.

Results

Participants achieving ≥ 15% WL more frequently reported reduced energy intake, reduced fat and sugar consumption, and regular physical activity at both 6 and 12 months compared with those achieving < 5% WL (all p < 0.03). Individuals in the ≥ 15% WL group reported a greater number of successful strategies at both time points (p < 0.001).

Conclusions

These findings from a clinical setting largely corroborate previous registry‐based evidence, demonstrating that clinically significant weight loss achieved during structured obesity treatment is associated with more frequent reporting of behaviors identified by the National Weight Control Registry.

Several behavioral strategies are associated with weight loss and weight loss maintenance. Behavioral strategies including restricting energy intake, limited intake of fat and sugars and regular physical activity were reported more frequently by patients with severe obesity who lost ≥ 15% of total weight compared with those who lost < 5%.

1. Introduction

Sustained weight loss requires a persistent reduction in energy intake combined with increased energy expenditure. Accordingly, clinical guidelines for obesity treatment emphasize dietary energy restriction, increased physical activity, behavioral modification and individualization as the cornerstones of medical obesity treatment [1, 2, 3]. The ability to maintain a negative energy balance over time is influenced by both internal factors, such as biological and psychological mechanisms, and external factors, including environmental and social influences [4, 5].

The National Weight Control Registry (NWCR) pioneered the systematic identification of behavioral strategies associated with successful long‐term weight loss maintenance [6, 7, 8, 9]. Established in 1994, the registry includes individuals who have lost at least 13.6 kg (30 lb) and maintained this weight loss for a minimum of 1 year [6, 9]. The NWCR comprises more than 10,000 participants, approximately 80% of whom women are, and participants have been followed for over 10 years [10]. Analyses of NWCR data have identified seven key behavioral factors associated with successful weight loss maintenance, including reduced energy intake and consumption of a low‐fat, low‐sugar diet [6, 10, 11], regular self‐weighing [8, 10, 12], consistent meal patterns on weekdays and weekends and regular breakfast consumption [7], self‐monitoring of food intake and calorie counting [11], and high levels of physical activity [13, 14].

Several weight control registries with similar aims and inclusion criteria have since been established [15, 16, 17, 18]. Overall, findings from these registries are consistent with those from the NWCR. In a systematic review, Paixão et al. reported substantial overlap between strategies associated with weight loss and those associated with weight loss maintenance [19], as also found in NWCR. The most frequently reported behaviors among successful weight maintainers included having healthy foods available at home, regular breakfast consumption, increased vegetable intake, reduced intake of fatty and sugary foods, limiting specific foods, use of low‐fat cooking methods, regular meal frequency, and high levels of physical activity [19]. However, more than 30 distinct strategies were identified, with considerable interindividual variability in their prevalence [19].

Although the behaviors associated with weight loss can be mechanistically explained by their ability to induce a negative energy balance, psychosocial factors, including weight stigma [20], also play a critical role in both weight loss by different methods [21, 22, 23], over long‐term [21] and the maintenance of weight loss [23]. Successful weight loss has been associated with greater dietary restraint, stronger autonomous motivation, lower disinhibition, a lower self‐identified ideal weight, and regular self‐monitoring of body weight [23], which are in line with a previous review [24] and a 10‐year follow‐up of NWCR [10]. Using a machine learning approach, Yang et al. evaluated 138 variables to identify predictors of weight loss [25]. They identified lack of motivation, infrequent self‐monitoring, and a high snacking frequency as the three most important factors associated with lower weight loss and higher physical activity was associated with greater weight loss [25]. These findings suggest that psychosocial factors consistent with weight loss may mediate the effect of behavioral factors on weight loss and its maintenance [23].

In structured obesity treatment programs, the nadir of weight loss is usually achieved after 6–9 months, followed by partial weight regain thereafter [26, 27, 28]. It is therefore of interest to examine the extent to which weight maintenance success factors identified in the NWCR are reported within structured medical weight‐loss programs, and not only from registries. In a systematic review of weight control registries Paixão et al. [19], found similar strategies favorable for weight loss and weight loss maintenance as in NWCR.

Another aspect is the intensity of usage of weight loss behaviors and whether the intensity may change over time in a treatment program. In a study by De la Peña‐Armada et al. [29] including 1252 participants (BMI 28.8 ± 3.3 kg/m²) of a cognitive behavioral program, the authors found that energy‐ and alcohol intake were two of the most important behavioral factors, determined by patients, during the first period (0–6 weeks) in a 24‐week weight loss treatment program but not later. Thus, behaviors may change as well as fluctuate in intensity over time.

Also, in most behavioral weight loss studies, the BMI of the participants often includes overweight or obesity below 35 kg/m² or both. Thus, it is important to increase knowledge about groups of severe obesity in clinical treatment settings since the prioritization of patients to treatment will have higher BMIs and have more obesity‐related comorbidities [30].

The aim of this study was to assess the prevalence of self‐reported factors associated with successful weight loss and maintenance among patients with severe obesity who had completed a 12‐month structured medical weight‐loss program and to compare the frequency of reported behaviors between patients achieving ≥ 15% weight loss and those achieving < 5% weight loss.

2. Methods

2.1. Subjects

This retrospective study included 313 consecutive patients referred to the Obesity Unit at Sahlgrenska University Hospital, Gothenburg, Sweden, for obesity management during 2018–2019. Patients aged ≥ 18 years with a BMI ≥ 35.0 kg/m² were eligible for referral to the unit. The study was approved by the Regional Ethical Review Board at the University of Gothenburg (applications 496‐16 and 2020‐05391) and conducted in accordance with the Declaration of Helsinki. Individual informed consent was not required.

2.2. Very‐Low‐Energy Diet

The 12‐month medical obesity treatment program began with a period of very‐low‐energy diet (VLED) for eligible patients (VLED group). Daily intake consisted of three to five commercially available VLED portions, providing 600–900 kcal/day depending on brand, with standardized macro‐ and micronutrient content. The duration of the VLED phase was determined by baseline BMI: 12 weeks for BMI 35.0–39.9 kg/m², 16 weeks for BMI 40.0–49.9 kg/m², and 20 weeks for BMI ≥ 50.0 kg/m². Average weight loss during the strict VLED phase was approximately 1–2 kg per week, depending on baseline BMI.

During the strict VLED phase, patients met with a nurse every 3 weeks. Following this phase, solid foods were gradually reintroduced, starting with one main meal every 6 weeks and beginning with breakfast. Individual energy requirements were estimated using the Mifflin‐St Jeor equation [31], and a 30% energy reduction was applied to promote continued weight loss [1]. During the food reintroduction phase and thereafter, patients met with a dietitian approximately once per month until the end of treatment.

Certain medical and psychiatric conditions were considered contraindications to a strict VLED phase, including type 1‐diabetes, severe cardiovascular or renal disease, major psychiatric disorders, severe eating disorders, pregnancy, or lactation [32]. Patients with these conditions were not eligible for the VLED program. All patients underwent individual safety assessments and were closely monitored throughout the 12‐month treatment period. Approximately 85% of referred patients were eligible for and initiated the strict VLED phase.

2.3. Dietary Treatment Without VLED

Patients not eligible for the VLED program were offered dietary treatment without VLED (DIET group). This intervention consisted of an energy‐restricted meal plan initiated at treatment start, based on the same estimation of daily energy requirements used in the VLED group. Patients were encouraged to use one meal replacement per day in order to secure energy restriction over time. Dietary counseling was individualized and focused on establishing regular meal patterns, portion control, food selection for weight loss and maintenance, and general health, as well as advice on daily physical activity. After food reintroduction, patients in the VLED group received the same dietary counseling as the DIET group.

2.4. Evaluation of Treatment Effect

After 3 months of treatment, patients in the VLED and DIET groups were required to achieve ≥ 10% and ≥ 5% weight loss; otherwise, treatment was discontinued. Some patients who have achieved ≥ 10% and ≥ 5% weight loss after 3 months may have regained their weight later in treatment. In the present study, only patients who completed the 12‐month treatment and achieved either ≥ 15% or < 5% weight loss were included for analyses. Patients achieving ≥ 5% and < 15% weight loss were excluded since we wanted to include patients only in lower (< 5%) and upper (≥ 15%) end of the weight loss interval.

2.5. Data Collection

2.5.1. Electronic Medical Record Review

Seven key behavioral factors associated with weight loss and weight maintenance, identified in the NWCR [7] were investigated (Table 1). A standardized data extraction template was developed, and electronic medical records were systematically reviewed for documentation of these factors. Each factor was coded as present (1) or absent (0). If at least one record indicated use of a given behavior, it was coded as present. In cases of contradictory information, the factor was coded as absent.

TABLE 1.

Factors associated with successful weight loss maintenance according to the National Weight Control Registry ^a .

Success factor	Description
1. Reduced energy intake	Adheres to dietary recommendations (approximately 1200–1800 kcal/day). Uses calorie counting to support lower energy intake. Consumes smaller portion sizes and increases vegetable intake
2. Reduced intake of fat and sugar	Limits consumption of high‐fat and/or high‐sugar foods such as sweets, candy, pastries, cookies, sugary beverages, and ice cream. Fast food is consumed rarely or not at all
3. Regular meal frequency	Eats a consistent set of meals at habitual times throughout the day. Avoids frequent snacking between main meals. Meals are consumed in a structured and regular pattern
4. Regular breakfast consumption	Consistently consumes breakfast, with no indication of breakfast skipping
5. Regular self‐weighing	Weighs oneself regularly, either at home or in addition to mandatory weigh‐ins at the obesity clinic
6. Self‐monitoring of food intake	Uses a food diary to monitor energy intake and/or eating patterns, either digitally (e.g., an app) or on paper
7. Regular physical activity	Engages in moderate‐ to high‐intensity physical activity at least two or more times per week

^a Wing and Hill [7].

Records from dietitians, nurses, and physicians were reviewed at both 6 and 12 months. Journal entries immediately before, after, and closest to the 6‐ and 12‐month visits were reviewed (three entries per time point). When entries were contradictory (e.g., “exercises daily” vs. “no exercise”), the factor was coded as absent due to inconclusive evidence. If two or more entries confirmed a factor, it was coded as present. If only one of the three entries mentioned the factor, that entry determined the coding. Comments were recorded for each coding decision to ensure consistency and minimize bias.

A pilot review was conducted by first author A.H. in collaboration with author I.L. to define each success factor. Data extraction was performed by the first author (A.H.).

2.5.2. Anthropometry

Height was measured at baseline using a wall‐mounted stadiometer to the nearest 0.5 cm. Body weight was measured at 6 and 12 months to the nearest 0.1 kg using calibrated scales (Soehnle Professional, Backnang, Germany), with participants wearing light indoor clothing and no shoes.

2.6. Statistical Analysis

Descriptive data are presented as mean ± standard deviation. Student's t‐test was used to compare continuous variables between weight loss groups (≥ 15% vs. < 5%). Categorical variables are presented as medians (minimum–maximum) and compared using Fisher's exact test. The prevalence of success factors is presented as percentages. The Mann–Whitney U test was used to compare the total number of success factors between groups. Statistical significance was set at p < 0.05 (two‐tailed). Analyses were performed using IBM SPSS Statistics, version 28 (IBM Corp., Armonk, NY, USA).

3. Results

Of the 313 patients included, 147 completed the 12‐month treatment program (Figure 1). In total, 166 patients (53%) discontinued treatment. There were no significant differences between completers and non‐completers with respect to baseline age (45.0 ± 14.3 vs. 47.1 ± 15.1 years, p = 0.269) and BMI (42.7 ± 7.6 vs. 42.2 ± 5.7 kg/m², p = 0.544). Among non‐completers, 23 patients (13.9%) had their treatment terminated at 3 months due to insufficient weight loss. Other reasons for discontinuation included desire for bariatric surgery, adverse effects of VLED, pregnancy, repeated missed visits, and personal reasons.

FIGURE 1.

Flowchart of individuals included and excluded in the analyses.

Among the 147 completers, 83 (56.5%) achieved ≥ 15% weight loss and 10 (6.8%) achieved < 5% weight loss. Electronic medical records were unavailable for five patients, resulting in a final analytical sample of 88 patients (Figure 1).

3.1. Weight Loss Groups

Baseline characteristics and 12‐month weight changes are presented in Table 2. The two weight loss groups did not differ with respect to sex distribution, age, height, body weight, or BMI. Prevalence of diabetes was significantly higher in the ≥ 15% group compared with the < 5% group (p < 0.05), while prevalence of hypertension and psychiatric disorders did not differ between the groups. The ≥ 15% weight loss group included a higher proportion of patients treated with VLED, whereas the < 5% group received dietary treatment more frequently without VLED. Mean 12‐month weight change was −25.4 ± 8.6% in the ≥ 15% group and 1.2 ± 8.4% in the < 5% group (p < 0.001) (Table 2).

TABLE 2.

Baseline characteristics for the < 5% and ≥ 15% weight loss groups and weight change at 12 months.

Weight loss group	< 5%	≥ 15%	p‐value
Numbers	9	79
Age (years)	56.2 ± 11	46.1 ± 15.2	0.056
Women, n (%)	7 (77.8)	60 (75.9)	1.0
Height, cm a	165.9 ± 9.9	168.3 ± 8.8	0.451
Weight, kg a	111.8 ± 23.4	120.6 ± 22.9	0.277
BMI, kg/m2 a	40.3 ± 4.8	42.4 ± 5.8	0.299
VLED, n (%)	3 (33.3)	77 (97.5)	0.007
Diet, n (%)	6 (66.6)	2 (2.5)	0.007
Weight change 12 months, (%)	1.2 ± 8.4	−25.4 ± 8.6	< 0.001
Hypertension, n (%)	5 (55.5)	29 (36.7)	0.29
Diabetes, n (%)	4 (44.4)	11 (13.9)	< 0.05
Psychiatric disorders, n (%)	4 (44.4)	21 (26.6)	0.26

^a Mean ± SD.

3.2. Total Success Factors at 6 and 12 months

At 6 months, patients in the ≥ 15% group reported more frequent use of three to six success factors, whereas patients in the < 5% group most commonly reported zero to three factors (Figure 2a,b). At 12 months, patients in the ≥ 15% group reported the use of zero to six factors, while those in the < 5% group reported zero to two factors (Figure 2c,d). The total number of success factors differed significantly between groups at both time points (p < 0.001) (Table 3).

FIGURE 2.

(a–d). Number of patients and in percent in relation to reported number of success factors used in ≥ 15%‐group (a) and < 5%‐group (b) at 6 months and in ≥ 15%‐group (c) and < 5%‐group (d) at 12 months.

TABLE 3.

Prevalence of success factors in < 5% and ≥ 15% weight loss groups at 6‐ and 12‐months.

	6 months		p	12 months		p
	< 5% group	≥ 15% group		< 5%	≥ 15% group
Numbers	9	79		9	79
Decreased energy intake, n (%)	1 (11.1)	72 (91.1)	< 0.001	0 (0)	47 (59.5)	< 0.001
Decreased intake of fat and sugar, n (%)	1 (11.1)	71 (89.9)	< 0.001	1 (11.1)	43 (54.5)	0.03
Regular meal frequency, n (%)	0 (0)	12 (15.2)	0.351	1 (11.1)	27 (34.2)	0.262
Regular breakfast intake, n (%)	8 (88.9)	70 (88.6)	1.0	5 (55.6)	45 (57.0)	1.0
Regular self‐weighing, n (%)	1 (11.1)	7 (8.9)	1.0	0 (0)	6 (7.6)	0.626
Self‐monitoring of food intake, n (%)	0 (0)	14 (17.7)	0.344	0 (0)	14 (17.7)	0.344
Regular physical activity, n (%)	2 (22.2)	56 (70.9)	0.007	1 (11.1)	55 (69.6)	< 0.001
Total success factors, median (min, max)	1 (0, 3)	4 (0, 6)	< 0.001	1 (0, 2)	3 (0, 6)	< 0.001

Note: Statistically significant p‐values in bold, otherwise not statistically significant.

3.2.1. Individual Success Factors

At both 6 and 12 months, the ≥ 15% weight loss group more frequently reported reduced energy intake, reduced intake of fat and sugar, and regular physical activity compared with the < 5% group (Table 3). No significant group differences were observed for regular meal patterns, breakfast consumption, or self‐monitoring of body weight or food intake at either time point.

4. Discussion

This retrospective study, based on data manually collected from electronic patient records, found that patients who achieved ≥ 15% weight loss more frequently reported the use of well‐established success factors for weight loss and weight maintenance compared with those who lost < 5% of their body weight after 6 and 12 months of obesity treatment. The total number of reported success factors was significantly higher in the ≥ 15% group than in the < 5% group.

All patients met the criteria for severe obesity, consistent with the minimum referral criterion for obesity treatment of a BMI ≥ 35 kg/m² and the average baseline BMI of 41 kg/m². This patient population did not differ from previous study populations at our outpatient clinic in terms of percentage of women, age, and baseline BMI [33, 34]. There were more patients with diabetes in the ≥ 15% group although the numbers in each group were low. One reason may be the treatment modality including an initial period of VLED that has previously been shown to be effective for weight loss in type 2‐diabetes [35, 36]. The proportion of patients with psychiatric disorders did not differ between the weight change groups. Although major psychiatric disorders are contraindications for the use of strict VLED [32], we have previously shown that well‐controlled psychiatric disorders are not contraindicative to strict VLED [33].

The marked divergence in weight change between groups, one group losing approximately 25% of body weight and the other gaining approximately 1% after 12 months is partly explained by treatment discontinuation among patients who did not achieve clinically significant weight loss (5%–10%) [1] after 3 months. Additionally, early weight loss during treatment increases the likelihood of continued participation and program completion [28]. Consequently, more patients remained in the ≥ 15% group than in the < 5% group at 12 months. However, some patients who initially achieved the weight‐loss goal subsequently regained weight during the second half of the program and were therefore categorized in the < 5% group. By focusing on patients at the extremes of weight change (i.e., those with the greatest and least weight loss), as one of the study aims, the analysis allows identification of similarities and differences that may not be apparent when comparing patients above and below the mean weight change. The downside of excluding the mid‐weight loss group is the loss of information about behaviors in that group and thereby the statistical power in the analyses may be limited.

A majority of patients in the ≥ 15% group reported restriction of energy intake more frequently than those in the < 5% group at both 6 and 12 months. Findings from metabolic ward studies, in which energy intake and expenditure are tightly controlled, demonstrate that the magnitude of energy deficit is the primary determinant of weight loss [37, 38]. This is also supported by data from the NWCR, where dietary energy restriction was identified as the most important factor for both weight loss and long‐term maintenance [7, 10]. Clinical strategies to reduce energy intake include following an individualized energy controlled meal plan, portion control, choosing low energy‐density foods, and limiting consumption of high energy‐density foods [39].

Furthermore, a greater proportion of patients in the ≥ 15% group reported reduced intake of fat and sugar compared with the < 5% group. Highly palatable foods such as sweets, chocolate, baked goods, and ice cream are typically high in fat and sugar and contribute substantially to total energy intake [40], potentially enhancing their appetite‐stimulating properties [5]. Sugary and fatty foods often have low micronutrient density; therefore, substituting energy‐dense foods with foods of lower energy density reduces total dietary energy intake while increasing micronutrient intake.

Patients in the ≥ 15% group also reported significantly higher levels of regular physical activity than those in the < 5% group. Physical activity is a key success factor identified in the NWCR, alongside energy intake restriction and self‐monitoring of body weight [7, 10], and has been corroborated in other weight control registries [17, 19]. Although physical activity alone has a limited effect on weight loss in the absence of energy restriction, it plays an important role in weight maintenance [41]. In addition, the cardiovascular benefits of regular physical activity are well established and should not be underestimated. Accordingly, physical activity is a central component of clinical guidelines for obesity treatment [2, 3].

The total number of reported success factors was significantly higher in the ≥ 15% group than in the < 5% group. These findings support previous evidence that incorporating multiple success factors into a healthy lifestyle is important for both weight loss and long‐term weight maintenance [10]. From a clinical perspective, it is essential to individualize these factors to ensure their practical effectiveness in daily life for each patient.

Regular meal patterns, regular breakfast consumption, and self‐monitoring of body weight and food intake, were reported with similar frequency in both groups. During nutritional counseling, all patients were instructed to follow a regular meal pattern and to consume breakfast daily, and these behaviors appeared to be adopted regardless of the weight‐change outcome.

Body weight was measured at every clinic visit throughout the 12‐month program. Although patients were encouraged to weigh themselves weekly at home, regular clinic‐based monitoring may have influenced this behavior. A systematic review and meta‐analysis of randomized controlled trials found that self‐weighing alone did not significantly improve weight outcomes but contributed to weight loss when combined with multicomponent interventions [42]. Other reviews have shown that regular self‐weighing is associated with weight loss regardless of intervention type [12, 43], and is not associated with adverse psychological outcomes [44], and may help prevent weight regain [45]. Although not directly assessed in this study, regular self‐weighing appears to be an effective strategy for supporting weight loss and weight maintenance.

Self‐reported behaviors during obesity treatment should not be interpreted in isolation. Psychological and psychosocial factors [21, 22, 24] and motivation [29] not captured in the present study may influence both engagement in and the intensity of behavioral change. Stress is one psychosocial factor that may exert physiological effects such as alterations in adipose tissue distribution mediated through interactions between the endocrine and immune systems as well as psychological effects relevant to obesity [46]. Consequently, stress [46] and other psychosocial correlates may modulate both behavioral change processes and treatment outcomes [23, 24, 25].

Emotional dysregulation, including emotional eating and loss of control over eating, may further interact with the behavior change process on a daily basis [47] and represents an important component of overall mental health [48]. Additionally, a history of dieting and weight cycling may increase anxiety and stress when seeking obesity treatment [49]. Social stigma and discrimination may also influence behavior change; for instance, patients may encounter questioning or opposition from family members or colleagues regarding their efforts to adopt lifestyle changes aimed at weight reduction that become a mental burden for the patient [20].

Within a structured behavioral treatment framework, physiological aspects of weight change, as well as psychological and social dimensions of obesity, and the interactions among these factors can be assessed and addressed in an individualized manner. This approach enables patients to acquire and apply practical, evidence‐based strategies that are effective in everyday life [50].

The strengths of this study include data collection from a structured obesity treatment program with monthly follow‐up visits in patients with severe obesity. The health care personnel were unaware that patient records would later be analyzed, as the study was conducted retrospectively, reducing the risk of reporting bias. Data were collected in a structured manner to minimize bias. Another strength is the focus on patients with the greatest and least weight change, which may increase the likelihood of identifying meaningful differences in the use of success factors. Additionally, the success factors examined are well supported in the literature and can be mechanistically linked to weight loss and weight maintenance.

Several limitations should be acknowledged. First, the small sample size, particularly in the < 5% weight loss group, limited the statistical power of the analyses. In combination with the retrospective study design and the reliance on information obtained during face‐to‐face consultations that was subsequently interpreted and summarized in electronic medical records, this may have introduced bias, including variability in the documentation of patient‐reported behaviors by healthcare professionals. However, because neither patients nor healthcare staff were aware of the planned analyses, the medical records are likely to reflect routine clinical documentation.

Second, the study included patients from two treatment interventions, an initial very low‐energy diet (VLED) followed by dietary counseling, and dietary counseling with an energy‐restricted diet alone, which were associated with different expected weight loss trajectories. In the < 5% weight loss group, 6 of the 9 participants had received the diet‐only intervention, potentially introducing selection bias. Moreover, patients allocated to the diet‐only intervention had contraindications to VLED, such as severe psychiatric disorders, which may have limited their ability to achieve greater weight loss. Nevertheless, inclusion of both treatment approaches was intended to increase the generalizability of the findings to routine clinical practice.

Third, the assessed behaviors were analyzed as binary variables, precluding evaluation of the intensity or degree of engagement in each behavior. Furthermore, each of the seven National Weight Control Registry (NWCR) behavioral domains encompasses several distinct behaviors. For example, the domain “reduced energy intake” includes limiting portion sizes, reducing consumption of energy‐dense foods, increasing intake of low energy density foods such as vegetables and fruits, and decreasing consumption of confectionery, fast food, sugar‐sweetened beverages, and alcoholic beverages. Because the data were retrospectively extracted from electronic medical records documented by dietitians, nurses, and physicians, the behavioral coding relied on identifying specific terms and descriptions corresponding to these broader behavioral domains across documentation from all three professional groups. This methodological approach also explains why not all behavioral domains described in weight control registries were included in the present analysis.

Finally, as part of the obesity treatment program, patients who failed to achieve at least 5% weight loss after 3 months discontinued treatment. Restricting the analyses to the two extreme weight loss groups (< 5% and ≥ 15%) may therefore have introduced additional selection bias, contributing to the small size of the < 5% group (n = 9) relative to the ≥ 15% group (n = 79).

This study was conducted in adults with severe obesity participating in a structured obesity treatment program. Because the behavioral factors identified by the National Weight Control Registry have been consistently associated with successful weight management across populations with lower BMI and in other weight control registries, the findings of the present study may be generalizable to broader populations with obesity, including individuals outside structured obesity treatment programs.

In conclusion, the present study extends previous findings from populations with lower BMI by demonstrating that, among patients with severe obesity, well‐established weight management behaviors, including dietary energy restriction through low‐fat, low‐sugar dietary patterns and regular physical activity, are associated with clinically meaningful weight loss. These behaviors can be identified within routine clinical practice and may represent important targets for behavioral interventions in structured obesity management programs.

Author Contributions

A.H. and I.L. contributed to the conception and design, planning, analysis, interpretation of data and writing of the manuscript. A.H., S.B., E.A.K., B.E., and I.L. contributed to data interpretation and have critically revised the manuscript. All authors have approved the submitted version of the manuscript.

Funding

The authors have nothing to report.

Conflicts of Interest

A.H. is currently employed by Yazen Health. This employment began after the completion of the study. Yazen Health has no scientific, economic or other role in the study. B.E. reports personal fees from NovoNordisk, Eli Lilly, Sanofi, Abbott and Amgen outside the submitted work. I.L. reports personal fees from NovoNordisk, Eli Lilly, Bristol‐Meyer‐Squibb and Janssen‐Cilag outside the submitted work. A.H., S.B., and E.A.K. report no conflicts of interest related to this study.

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.