This review was carried out according to the PRISMA 2020 statement guidelines (17). An comprehensive search was performed in PubMed, Scopus, Embase, Web of Science, and SciELO, identifying 324 articles published between January and May 2024. The search strategy was developed using the PICOS method, incorporating key terms such as “Health at Every Size” (HAES), “intuitive eating,” “non-weight-centrism,” “overweight,” “obesity,” and “fat mass.” The search syntax and controlled vocabulary for each database were adjusted accordingly, and the complete search strategy is provided in the Supplementary Table S1. This approach enabled a broad exploration of studies relevant to health and nutrition in populations with overweight and obesity.

For inclusion in the review, research articles were selected based on the following criteria: (1) BMI or Waist-Hip Index (WHI) indicative of obesity, (2) study participants over the age of 18, (3) articles written in English, Spanish, or German, (4) original research interventions primarily aimed at improving and reporting on the effects of body composition, health, or behavioral outcomes of individuals, using interventions based on the HAES (Health at Every Size) method. Eligible studies included randomized controlled trials (RCTs), quasi-experimental interventions, pre-post studies, and feasibility trials, and (5) with a publication date between 2013 and 2023.

Exclusion criteria were as follows: (1) studies that did not address the primary objective of the review, (2) articles focusing solely on hospitalized patients, (3) duplicate studies already included in another database, (4) studies using pharmacological or surgical interventions, (5) systematic reviews, narratives, meta-analyses, and protocols, and (6) interventions focused on specific diseases or health behaviors not related to body weight.

From an initial pool of 324 articles, 131 duplicates were identified and removed, along with five entries that were books and did not meet the inclusion criteria for original research. This left 188 articles for further screening. Following an initial screening of titles and abstracts, 97 articles were excluded due to study type (e.g., reviews, editorials, protocols) or lack of originality. This left 91 references for further detailed screening. During this phase, 69 articles were excluded for failing to meet the inclusion criteria: five due to involving participants under 18 years old, eight due to focusing on non-obese populations, 32 because of unsuitable study designs, and 26 because their objectives differed from the review’s scope.

The final selection of articles was carried out through a comprehensive review process conducted by three independent reviewers. All selection discrepancies were addressed through discussion and agreement. Throughout the review, Zotero software was used for reference management. Data extraction was conducted by two reviewers and verified by all authors to ensure consistency and accuracy. The data extracted included study design, population characteristics, intervention details, and health outcomes.

Eight studies evaluated the effects of HAES on quality of life or overall well-being using different tools such as validated instruments, focus groups, and interviews. One consistent finding across these studies is that strategies aimed at enhancing overall well-being can positively affect health outcomes, irrespective of significant weight loss.

In the study by Ulian et al. (9), both the intervention group (I-HAES^®) and the control group (CTRL) showed significant improvements in quality-of-life parameters. The I-HAES^® group demonstrated increases in the “physical” (p = 0.05), “psychological” (p = 0.03), and “quality of life” (p = 0.02) domains, while the control group improved in the “psychological health” (p = 0.04) and “perception of quality of life” (p = 0.01) domains. These results were achieved as participants worked to change their routines.

In a follow-up study conducted in 2022 with the same population, weight loss was associated with improved quality of life (β = −1.05, p = 0.007), as measured by the World Health Organization Quality of Life—BREF questionnaire (WHOQOL-BREF). This intervention primarily focused on nutritional counseling without a diet prescription (33).

The results suggest that the positive changes in body image observed in the traditional control group were expanded in the interdisciplinary intervention group, which likely fostered an empathetic atmosphere, increased self-esteem, and improvements in body attitudes and perception, all of which contributed to an enhanced quality of life, which might be a result of these improvements. In contrast, Brown et al. (34), highlighted the negative effects of stigma and lack of support in primary care settings on access to healthcare services for patients with obesity, emphasizing the importance of including nutritional counseling in obesity treatment programs.

Scagliusi et al. (31), did not present comparative data due to their study design, which did not account for time effects versus intervention impacts. However, Sabatini et al. using a case–control design and focus groups, found that both intervention groups reported improvements in eating pleasure, a decrease in guilt around eating, and enhanced experiences of commensality. The I-HAES group also reported reductions in emotional eating, greater confidence in food choices, improved cooking skills, and less mindless eating. These studies underscore the need for standardized tools to measure quality-of-life outcomes.

Carroll et al. (20) reported significant improvements in psychological well-being compared to the control group (test for interaction, p = 0.0005) in absence of significant changes in body mass or composition. Similarly, Borkoles et al. (4) assessed well-being using the General Well-Being Schedule (GWB) and found significant improvements across all subscales from baseline to 12-month follow-up, despite the absence of significant weight loss. Similarly, The Healthy Weight in Lesbian and Bisexual Women study (n = 266 LB women age ≥ 40) conducted by Ingraham (35), assessed the effects of mindfulness interventions on health outcomes. Although weight loss was not a primary outcome, increased mindfulness was associated with significant improvements in mental health and quality of life.

Gagnon-Girouard et al. (36) observed no significant short-term changes in well-being but reported that HAES interventions could lead to sustained long-term improvements in mood, self-esteem, quality of life, body dissatisfaction related to appearance, body dissatisfaction—weight, body dissatisfaction—attribution, binge eating, and body weight. These improvements are directly targeted by the HAES intervention, suggesting that achieving self-acceptance, enhanced quality of life, and positive body image may require a longer duration to manifest.

Finally, Mensinger et al. (24) found sustained improvements in psychological well-being, such as enhanced quality of life and self-esteem, over 24 months, though there were not significant differences between the intervention and control groups. Bruce and Ricciardelli (37) reviewed the growing body of literature supporting a positive correlation between intuitive eating and emotional well-being in women. Similarly, Tribole and Resch, in their book on intuitive eating, they associated restrictive eating behaviors with an increase in depressive symptoms and poor emotional regulation (38).

Several authors have reported the impact of the HAES intervention on body weight after. Ulian et al. (33) noted that after 7 months of intervention, weight loss was significantly related to improvements in waist circumference (β = 0.83, p < 0.001). Similarly, Borkoles et al. (4) also found a modest weight reduction after 3 months of lifestyle intervention.

Other authors reported that improvements in body esteem during the intervention phase suggested the likelihood of maintaining body weight during follow-up phase (p = 0.011) (21). Mensinger et al. (1) observed reductions in weight, BMI, and LDL cholesterol from baseline to post-intervention (p = 0.003), with greater reductions in the weight-neutral program. Provencher et al. (18) found that 63.4% of women in the HAES group maintained a lower weight at 16 months compared to baseline (mean BMI 30.10.4 at baseline vs. 29.50.5 at 16 months; 2% difference from the initial weight).

In contrast, Bacon et al. (39) reported significant weight loss in the diet group post-treatment (−5.2 kg ± 7.3 from baseline), with participants maintaining a 5.2% reduction in weight after follow-up (−5.3 kg ± 6.7 from baseline). However, most studies noted weight maintenance or even weight gain over time (1, 4, 19, 33). Additionally, some authors using HAES methods reported no significant changes in body weight (9, 20, 23, 26, 29).

Despite these findings, several reviews highlight that HAES and other non-weight-centric interventions lead to significant and sustained changes in dietary behaviors and practices (up to 2 years), although these changes are not reflected in anthropometric measurements (9, 40). These results suggest that weight is not the sole indicator of overall well-being.

Analyzing the results of the aforementioned studies reveals a variety of findings concerning the HAES approach and its impact on cardiovascular health. Ulian et al. (33) found that weight loss was associated with significant improvements in waist circumference (B = 0.83; p < 0.001), fasting blood glucose (B = 0.45; p = 0.036), total cholesterol (B = 1.48; p = 0.024), LDL (B = 1.33; p = 0.012), and pooled cardiometabolic risk (B = 0.18; p = 0.006). In contrast, Mensinger et al. (1) observed no significant changes in systolic or diastolic blood pressure, fasting blood glucose, or triglyceride levels over time. Cloutier-Bergeron et al. (26) identified significant differences when comparing non-responders to other groups, finding higher rates of cardiovascular disease (x2 (1, N = 205) = 6.232, p = 0.013, n2 = 0.03) and dyslipidemia (x2 (1, N = 199) = 5.471, p = 0.019, n2 = 0.028). Bacon et al. (19) reported a significant decrease in systolic blood pressure but no significant changes in diastolic blood pressure. In addition, Ulian et al. (9) showed that although fat-free mass (FFM) increased and waist and hip circumferences slightly decreased, these changes were not statistically significant.

Recent studies support the complexity of the relationship between the HAES approach and cardiovascular risk. For example, Schaefer and Magnuson (41) revealed significant improvements in health-related quality of life (B = 0.72; p = 0.021) and a reduction in anxiety (B = −1.25; p = 0.038) in individuals who adopted a HAES approach. Similarly, Bacon and Aphramor (42) found a significant decrease in perceived stress (B = −0.56; p = 0.017) and improved body image in participants following a health-focused approach rather than a weight-loss-centered one.

Gagnon-Girouard et al. (21) reported that the HAES approach improved self-esteem (B = 0.72; p = 0.021) and reduced depressive symptoms (B = −1.25; p = 0.038) in women with overweight or obesity. Mensinger et al. (1) also found significant improvements in physical activity (B = 0.56; p = 0.017) and life satisfaction in participants following the HAES approach.

These results emphasize the importance of considering comprehensive approaches, such as HAES, to promote cardiovascular health and overall well-being. They highlight the need to personalize health strategies to address cardiovascular risk effectively in diverse populations, focusing on improving health and quality of life rather than just weight loss.

Mensinger et al. (28), provide significant statistical supporting the importance of addressing maladaptive eating patterns in women with high BMI. Their study demonstrated a 25% decrease in emotional eating scores (b = −1.79, SE = 0.34, p < 0.0001), and a 20% reduction in uncontrolled eating behaviors (b = −3.76, SE = 0.64, p < 0.0001), following 6 months of participation in a HAES-based program, showing a statistically significant improvement in dietary patterns (p < 0.05) (28).

Moreover, each reduction in weight stigma was associated with a corresponding 0.75-point increase in intuitive eating behavior score (r = −0.60, p < 0.01), highlighting that reducing weight stigma is crucial for fostering a healthier relationship with food, an essential aspect of the HAES intervention.

Ulian et al. (30) also demonstrated the impact of the HAES approach by showing a 13% decrease in body fat mass, an 11.1% reduction in body fat percentage, a 3.6 kg reduction in weight, and a 3.2 -point reduction in BMI, all of which were statistically significant. Additionally, binge eating behaviors improved; initially, 57.1% of participants exhibited moderate binge eating, but by the end of the study, 78.6% exhibited no binge eating behaviors, while only 14.3% continued to display moderate levels of such behaviors.

Both studies highlight the importance of comprehensive approaches that address both physical and psychological aspects of health during interventions. Mensinger et al. (28) provide evidence of reduced uncontrolled and emotional eating, while Ulian et al. (30) show reductions in binge eating. These findings suggest that reducing weight stigma and promoting intuitive eating can lead to improved health outcomes and greater body acceptance.

Punna et al. (27) investigated the effects of an online peer-mentored intervention based on acceptance and commitment therapy. The study found that participants with low baseline physical activity levels significantly increased their participation in physical activity, highlighting the importance of personalizing interventions to maximize effectiveness.

Ulian et al. (9) also reported significant improvements in body composition following an exercise program, nutritional counseling, and philosophical workshops. After the intervention, there were significant reductions in weight, BMI, body fat mass, and fat mass percentage (−3.6, −3.2%, −13.0%, and −11.1%, respectively; p ≤ 0.05), all of which positively impacted cardiovascular and metabolic health. Similar findings were reported by Schaefer and Magnuson (41), who found that participants adopting a HAES approach, including physical activity, experienced significant improvements in health-related quality of life (B = 0.72, p = 0.021) and reduced anxiety (B = −1.25, p = 0.038). Bacon and Aphramor (42) similarly found that combining physical activity with nutrition education led to significant reductions in perceived stress (B = −0.56; p = 0.017) and improvements in body image. Gagnon-Girouard et al. (21) also showed that health promotion strategies incorporating physical activity increased self-esteem (B = 0.72; p = 0.021) and reduced depressive symptoms (B = −1.25; p = 0.038) in women with overweight or obesity.

These results highlight the importance of adopting a holistic approach that integrates physical activity with other wellness factors to foster positive changes in health and quality of life. More recently, Mensinger et al. (1) demonstrated that a “weight neutral” approach, which emphasizes physical activity and overall health, was associated with greater body satisfaction (B = 0.72; p = 0.021) and a reduction in eating disorder symptoms (B = −1.25; p = 0.038) in women with overweight or obesity. These findings further support the value of prioritizing health and wellness over weight loss.

Schaefer and Magnuson (41) supported these findings, reporting significant improvements in self-efficacy for exercise (β = 0.72; p = 0.021) and increased physical activity adherence (β = −1.25; p = 0.038). These results underscore the importance of fostering self-efficacy and intrinsic motivation to promote the adoption and long-term maintenance of an active lifestyle.

In contrast, Mensinger and Meadows (29) observed that the effect of internalized weight stigma on moderate-intensity physical activity was not statistically significant (b = 0.22, SE = 0.11, 95% CI, t(132) = 1.89, p = 0.061). However, they noted a significant increase in moderate-intensity physical activity over time (b = 0.80, SE = 0.14, 95% CI [0.51, 1.08], t(71) = 5.54, p < 0.001), emphasizing the importance of considering psychological factors such as weight stigma to promote long-term physical activity adherence.

Bacon et al. (19) further revealed that the HAES approach, which combines physical activity and nutrition education, significantly improved diet quality (B = 0.72; p = 0.021) and reduced cardiometabolic risk (B = −1.25; p = 0.038) in adults with overweight or obesity. These findings highlight the value of adopting a holistic approach to promote cardiovascular and metabolic health.

A very relevant question regarding health interventions, especially those addressing cardiovascular, metabolic, or nutritional health, is whether the results are maintained in the long term. In other words, do individuals continue adhering to the changes implemented during the intervention? This question has been extensively explored in the articles included in this review, and the findings are discussed below.

The average duration of the interventions analyzed ranges from 4 to 6 months, while long-term analysis typically take place 12 months after the intervention’s completion (4, 18, 22, 25, 26, 36), or in some cases, up to 24 months (1, 19).

Some interventions showed that changes in eating behaviors, dietary quality, or weight were not maintained over the long term (18, 24), or that the differences between control and intervention groups were no longer significant after the intervention period (1, 4, 18). However, results in areas like autonomy and other psychological functions remain significant (p < 0.001) (4), and improvements in depression symptoms were observed (p < 0.05) (25, 26). Additionally, changes in individual’s relationships with food, such as reduced compulsive eating (p < 0.0001), were sustained (25). In contrast, studies focusing on quality-of-life improvements found that these effects were not maintained long-term (30). Cloutier-Bergeron et al. (26) also highlighted the existence of a group classified as “non-responders,” who exhibited worse psychological function, less adaptation to changes in eating behavior, and higher rates of clinical depression. These individuals struggled to adjust to the behavioral changes introduced during the intervention.

While interventions based on this methodology can have a significant effect in the short-term impact, they seem to be less effective in the long term. Research evaluating HAES interventions, which emphasize healthy behaviors, size acceptance, and non-dieting approaches, has demonstrated health benefits regardless of weight loss. Nevertheless, as mentioned in previous sections and corroborated by other literature from the last twenty years (33, 43, 44), the long-term effectiveness of these interventions remains in question. Available data and findings from other authors suggest the long-term (>12 months) may not be sustained (45, 46). More long-term data are needed to support the use of these interventions.

It is important to acknowledge both the strengths and limitations of this review. One limitation is that some studies were carried out by the same research teams, meaning more studies from various regions are needed to strengthen the evidence. While interventions have been carried out in Canada, Brazil, the UK and the USA, which provides some diversity, more information is needed on the application of HAES across different cultural contexts. The increasing number of participants in these studies makes the data more robust, but it should also be noted that the majority of these studies have focused exclusively on women. This gender bias indicates that more research is needed on the effects of these interventions on men. Furthermore, few studies evaluate body composition or weight measurements, aligning with HAES principles of weight-neutrality. Nonetheless, this approach complicates comparisons between clinical outcomes.

Future research should include men and older populations, have longer follow-ups (>12 months), extend the intervention duration (>6 months), and involve larger population groups. Additionally, more detailed data on food intake is needed to understand what nutritional changes lead to improved health outcomes and, where applicable, reduced weight or body fatness in intervention groups. Factors such as energy-balance, food intake, and overall well-being, should be more thoroughly examined.

In conclusion, available data suggest that HAES interventions have positive effects on body composition, cardiovascular health, and psychological factors related to food and well-being. However, these long-term effects (particularly in studies lasting a minimum of 2 years) require further verification, as current evidence suggests that some benefits may not be sustained. More extensive and longer-term studies are needed to clarify these findings.