The rising prevalence of obesity emphasizes the urgent need for effective weight management strategies. Alternatives to conventional methods, such as diet alone, diet and exercise, exercise alone, meal replacements, very-low-energy diets, pharmacotherapy, and advice alone, are needed [5]. Despite the availability of commercial weight management programs, most of the interventions used in previous studies were not intensive and multicomponent, and their follow-up periods were relatively short to adequately demonstrate long-term weight loss [5, 10].
This study evaluated the effectiveness of a multicomponent behavioral weight management program, the WLM3P, in achieving and maintaining a clinically significant WL (≥ 5%) compared to a LCD. The primary findings from this 18-month study demonstrate that both WLM3P and LCD groups were successful in achieving and maintaining clinically significant WL ≥ 5%. Moreover, a higher proportion of participants in the WLM3P group reached higher %WL targets, such as WL ≥ 10% and 15%. These higher %WL targets have been associated with additional clinical benefits and are frequently more desirable for clinical purposes[5, 6].
The %WL and the proportion of participants losing 5% of their initial body weight observed in this study were higher than those reported in others intensive lifestyle interventions at 12-month (mean of WL = 8% and WL ≥ 5% = 66.3–70.2%)[8]. The %WL results achieved in our study are more comparable to the results reported in clinical research protocols that use pharmacotherapy for obesity treatment, which typically show %WL in the range of 6.5–14.9% [8]. Nevertheless, all these interventions are typically characterized by high attrition rates and weight relapse[5][10] [8]. In our study, from months 6 to 18, participants in both WLM3P and LCD groups experienced weight regain (< 5%), with no significant difference between the two groups. This resulted in net losses of 15.5% and 9.6%, respectively. Maintaining WL and preventing weight regain is critical, as it has a potential negative impact on body composition and cardiometabolic health[5, 6].
The 18 months intervention of WLM3P resulted in significant reductions in BMI, BFM, VFA, WHR, and WC, as well as improvements in HDL cholesterol and TG/HDL ratio (atherogenic index) compared with LCD (Fig. 2). It is critical to derive WL primarily from BFM as excess adiposity is highly associated with other metabolic diseases [1]. Nevertheless, some studies have shown that WL is accompanied by the loss of tissue from the fat-free compartment, particularly SMM [32]. Low SMM and high VFA are known to be associated with atherosclerosis, cardiovascular diseases, sarcopenic obesity, insulin resistance and nonalcoholic fatty liver [33, 34]. From baseline to 6 months, the S/V ratio, which captures changes in SMM and VFA, showed a significant improvement in the WLM3P group compared to LCD. These findings indicate that WLM3P can be more effective than LCD in maintaining a metabolically healthy state [33, 34].
Greater WL has been associated with improved lipid profile [5, 6], including increased levels of HDL cholesterol and reduced TG/HDL ratio, which are linked to lower risk of cardiovascular disease [35]. The WLM3P group showed a greater increase in HDL cholesterol in comparison with the control group and others popular diet programs [11]. Diet composition is an important determinant of HDL and TG metabolism [36]. According to a network meta-analysis and nutritional geometry approach, a low-carbohydrate/high-protein diet (comprising 30%TEI from protein, ≤ 40% from carbohydrate, and ≥ 35% from fat) similar to those prescribed to the WLM3P group, particularly during phase 3 (weight maintenance) is identified as the most effective in increasing HDL cholesterol and reducing TG [36] which might explain the superior benefits in HDL cholesterol levels and TG/HDL ratio obtained in this group.
Regarding to improvements in blood pressure, according to a systematic review and meta-analysis, WL of 5%-10% is expected to lead to larger reductions in SBP of 4.9 mmHg and DBP of 2.6 mmHg over 6 to 12 months[37]. A similar degree of reduction in SBP and DBP was observed for a superior WL in both groups of our study, possibly due to the mixed-status hypertension of participants (both hypertensive and non-hypertensive).
From a clinical perspective, the positive outcomes observed in both groups might be attributed to a number of factors, included: i) long intervention period that may help participants established new lifestyle habits [5], ii) high emphasis on diet quality[38], iii) reduction in TEI during WL [5], iv) dietary macronutrient composition [(a high-protein diet is reported to be effective in inducing WL, BF reduction, preservation of lean mass [15, 16] and lower weight regain in the short term (3–12 months)] [39], v) high attendance rates to sessions (superior than 60.5% reported by others WL intervention [40]), vi) adequate sleep duration (≈ 8 h that has been linked to better WL outcomes)[25], and vii) increase in the proportion of participants that achieve the recommended physical activity level of ≥ 500 MET-min/week compared to baseline.
Other components of the WLM3P program may also have positively influenced weight management. The WLM3P is a high-intensity intervention (24 sessions in 6 months) that can provide numerous benefits for WL, including personalized guidance, support, goal setting, nutritional education, and long-term success [5, 6]. Also, integrate TRE as a strategy. Pamela et al.[41] found that participants with obesity who completed 8 weeks of a 14:10 TRE schedule combined with a commercial WL program had a greater reduction in body weight compared to a 12:12 TRE schedule. Furthermore, a systematic review and meta-analysis indicated that TRE combined with calorie restriction effectively reduced body weight, BFM, and WC[20]. Prolonged nightly fasting (WL phase: median 13.5 hours and weight maintenance phase: median 13.1 hours) promotes a metabolic switch, where the primary source of energy shifts from glucose to fat and ketones, potentially improving anthropometric measurements and cardiometabolic health [20, 42]. Given the continued high interest in strategies for successful weight management, WLM3P program uses dietary supplements, vitamins, and minerals supplements, to prevent potential micronutrient deficiency[21, 22] and, bioactive compounds (i.e.: L-Carnitine, green tea, green tea, chromium) that can impact on satiety, lipid absorption and fatty acids beta-oxidation. The safety and efficacy of WL programs that use supplements as adjuncts have been poorly evaluated in randomized controlled trials[21, 22] making it difficult for health professionals to refer patients to evidence-based programs due to a lack of understanding of the role of supplements on obesity treatment.
In addition, WLM3P program has a mobile/web platform with visual progress charts, dietary prescriptions, and goals definitions, setting to enhance therapeutic adherence [24]. Several studies have explored the use of digital health solutions for obesity and have shown promising results in promoting eating behavior change and WL [23].
In our study, no serious adverse events were reported, and constipation was the most common adverse event, but at a lower rate than reported in other weight loss programs [10]. When considering a weight management program that includes dietary supplements with diuretic characteristics, it is important to monitor potassium and sodium levels[43]. These electrolytes balance was not affected by the WLM3P intervention (supplementary Table S3).
The withdrawal rate at 18 months in our study (31%) was slightly below the average for weight loss trials at 1 year (37%) [44]. One of the key strengths of our study is the extended period (18 months) of this randomized controlled trial, which allowed us to gather comprehensive and detailed information on weight changes across the study duration. However, it is important to acknowledge the limitations of this study. First, the small sample size might have limited the statistical power, primarily focusing on detecting differences in weight change between the two groups rather than secondary outcomes. Second, due to the study design, we are unable to distinguish between the individual components' effects of the WML3P, nor to analyze their interactions. Further research is needed to understand how each of the 7 components of WLM3P contributes and whether they have synergistic or additive effects on weight management. Third, the control group in our study received active treatment with weight loss and weight maintenance-specific feedback. This might have influenced the outcomes, as a high percentage of participants in both groups achieved WL of ≥ 5%. Fourth, we acknowledge that using self-reported questionnaires and dietary records for assessing food intake have limitations. Participants were informed to do written annotations and to take photos of daily meals (food and beverages) during the diet recording days, using measuring cups, spoons, and home scales. Food diaries were reviewed using a photographic manual for food quantification [45]. Despite implementing these strategies, there may still be biases and errors in the data collected. Future research with larger sample sizes is needed to obtain more robust and conclusive results.
Our trial demonstrated that the WLM3P program was highly effective in helping adults with obesity achieve significant and sustained weight loss. The WLM3P resulted in a mean weight loss of 15.5%, with a large proportion of participants (87.5%) reaching the clinically significant milestone of 5% weight loss at the 18 months mark. Notably, the WLM3P program outperformed the LCD group in terms of achieving higher weight loss targets of 10% and 15%, as well as providing additional clinical benefits such as reducing BMI, body fat mass, visceral fat area, waist-to-hip ratio, and TG/HDL ratio, while increasing HDL levels. These improvements have important implications for the management of obesity-related metabolic disorders. Although our study did not specifically isolate the effects of individual program components, it provided valuable evidence of the overall efficacy of multicomponent behavioral weight management programs. These findings contribute to the existing knowledge base and emphasize the potential of multicomponent behavioral weight management programs to address the growing obesity epidemic.