This systematic retrospective chart review evaluated the effectiveness of the Medifast 5 & 2 & 2 Plan as used by real-world customers at MWCCs for weight loss. The studied population was predominantly males (57%) and nearly all were in the higher obesity classes (92% Class II or III obesity), reflecting the demographics of clientele on this meal plan. In this population, the 5 & 2 & 2 Plan resulted in significant reductions in body weight over both 12- and 24-weeks. Initial weight loss was rapid (-1.56 kg/week over the first month) followed by a more moderate, yet steady and significant weight reduction over the entire study period (average of -1.04 and -0.79 kg/week over 12 and 24 weeks, respectively). Importantly, the 5 & 2 & 2 Plan was effective for achieving clinically meaningful weight loss of ≥ 5%, as outlined in recent obesity treatment guidelines [8
]: among those remaining on the meal plan, one-third lost ≥ 5% of their baseline body weight by 4 weeks, 3 out of 4 achieved this goal by 12 weeks, and over 88% achieved at least 5% weight loss at all times thereafter. Assessing weight loss at the Final Visit, irrespective of how long an individual was on the 5 & 2 & 2 Plan, represents a stricter measure of effectiveness as it accounts for attrition that took place prior to 24 weeks; by this measure, nearly two-thirds achieved clinically meaningful weight loss of ≥ 5% by their Final Visit on the 5 & 2 & 2 Plan. Results from the ITT analyses at 12 and 24 weeks were similar to the Final Visit results, thus providing another robust assessment of effectiveness.
The 5 & 2 & 2 Plan generally compared favorably to other published lifestyle interventions in similar populations, although direct study comparisons are challenging given the heterogeneity in intervention types, study duration and study design. The pooled mean weight loss in recent meta-analysis evaluating lifestyle interventions in short term studies (<6 month duration) of individuals with class II and III obesity was 7.2 kg (95% CI: 8.9, 5.5). These lifestyle interventions included a nutrition component (education, recommendations, caloric restriction, etc.) together with a physical activity component. The mean weight loss in this study (-12.9 kg at 12 wks and -19.3 kg at 24 wks in the completers and -10.6 kg at 12 wks and -12.6 kg at 24 wks in the ITT analysis) was greater than the weight loss reported in most, but not all, studies included in that meta-analysis [23
]. Weight loss on the 5 & 2 & 2 Plan in both the completers and ITT populations at 6 months also exceeded that reported in two other studies evaluating the effect of physical activity along with behavioral intervention and caloric restriction in extremely obese adults [26
]. Not surprisingly, given that caloric intake associated with the 5 & 2 & 2 Plan is higher (1,300-1,500 kcal/day), weight loss on the 5 & 2 & 2 Plan was less than that observed in extremely obese individuals following a physician-supervised very-low or low energy diet using meal replacements (usually<1,000 kcal/day) in conjunction with behavioral therapy [22
In addition to measuring changes in total body weight, changes in body composition were also assessed. While there were significant reductions in both lean and fat mass, the majority (68-80%) of weight loss came from fat mass. Considering that lean mass accounted for an average of 20 to 33% of the weight reduction in this study, this program performed well compared to typical losses of 36% to 40% for men and 31% to 33% for women [28
]. The retention of lean mass may be partially attributed to the extremely obese population studied, since large baseline fat mass appears to help spare lean mass loss during caloric deficit [29
]. However, it may also be linked to the macronutrient composition of the meal plan which provides approximately 135-175 g of high quality protein per day. With the group’s mean baseline weight of 149 kg, this translates to an estimated 0.9 to 1.2 g protein per kg body weight, thus exceeding the average daily requirement of 0.8 g/kg and providing levels similar to those considered ideal for muscle retention during weight loss [32
]. Likewise, preservation of lean mass has been observed in previous studies with mixed populations of overweight and obese individuals using other Medifast weight loss meal plans (the 5 & 1 Plan® and the 4 & 2 & 1 Plan™
which also provide >100 g of protein/day), also suggesting that the combination of meal replacements and conventional foods recommended in these programs is beneficial for preserving lean mass during weight loss [14
]. While increases in activity and exercise are encouraged, none of the previously mentioned Medifast programs included a structured exercise regimen, further underscoring the likelihood that the macronutrient composition contributes to the observed preservation of lean muscle mass.
The achievement of clinically meaningful weight loss was reflected in the concomintant improvements in blood pressure. A substantial proportion of individuals (between 42% and 61% depending on whether assessed by self-report or measured) had high blood pressure at baseline, and the mean baseline systolic and diastolic blood pressure of the group (139.8 and 89.9 mm Hg, respectively) was nearly in the hypertensive range. However, at the 12-week primary endpoint, the mean systolic and diastolic blood pressures (116.9 and 79.5 mm Hg, respectively) fell into the normal range. The magnitude of the reduction in blood pressure (-17.7 mm Hg systolic and -8.4 mm Hg diastolic at 12 weeks) is clinically important and is large enough to have a significant impact on cardiovascular disease risk [34
]. In fact, over 40% of individuals experienced an improvement in their blood pressure category at 12 and 24 weeks while on the 5 & 2 & 2 Plan. The apparent increase in the mean systolic blood pressure at 24 weeks appeared to have a basis in the small sample size rather than being representive of a true trend. Also of note with regard to cardiometabolic risk is the significant reduction (9.0 cm) in waist circumference at 12 weeks. This measure is an indicator of visceral fat which is linked to diabetes and cardiovascular risk [35
]. The reduction in waist circumference was directionally larger (-10.0 cm), but not significant at 24 weeks (p=0.109), a consequence of the small sample size.
Weight maintenance data in this study were limited by the small number of individuals (11%, n=7) who entered this phase. The available data indicate a non-significant trend toward partial weight regain (3.4% of baseline body weight), yet the overall mean weight change during the entire program (mean of 61 weeks over the Weight loss, Transition (as applicable) and Maintenance Phases) was significant (-34 kg, or 24% below the group’s baseline weight), suggesting the program was effective for weight loss and weight maintenance for the limited subset that entered the Maintenance phase.
All signs, symptoms and health-related incidents were collected and analyzed in a systematic fashion. When evaluated, these incidents were consistent with previously reported side effects [15
], primarily constipation, and general complaints of hunger, cravings, and stress which are also often associated with intentional weight loss. Both obesity and weight loss are known to be significant risk factors for the development of gallstones [36
], and one person (1.6%) experienced gallbladder pain/stones, ultimately requiring surgery. Aside from this cholecystectomy, only one other serious (unrelated) incident was reported. The observed rate of serious events (3.2%) is similar to placebo rates seen in pharmacotherapy trials with obese populations [38
]. Overall, the data suggest the 5 & 2 & 2 Plan was generally well-tolerated in this population of obese individuals.
One limitation of this study was the relatively small starting sample size (n=62) combined with attrition from the meal plan which, together, resulted in limited datasets, particularly at the later time points and for many of the secondary outcomes. Data at the primary endpoint, change in bodyweight at 12 weeks, was not available for approximately 40% of the starting study population. To address these concerns, tripartite analyses (completers, ITT and regression analyses) for body weight changes were conducted, the latter two of which accounted for missing data. All three analyses showed similar effectiveness, albeit with the greatest weight loss in the completer’s analysis. As previously noted, many individuals switched to other Medifast weight loss plans over time, and a portion of the difference between the completers and ITT results can be attributed to the large proportion (29%) of individuals, who as their BMI dropped to below 40 kg/m2
, switched, per center procedure, to other Medifast weight loss plan(s), and continued to lose weight. These were among the most successful individuals on the 5 & 2 & 2 Plan, thus reducing the overall observed weight loss at the later time points in the ITT analysis. Retention on the 5 & 2 & 2 Plan at 12 weeks (60%) was in the range observed with some other commercial weight loss programs (approximately 45-70%) , but was better if one considers the total proportion that continued on any of the Medifast weight loss plans at 12 weeks (n=48, 77%) [22
]. Another limitation was the retrospective nature of the study and absence of a control group. A larger, prospective, randomized, controlled trial could strengthen these results and address efficacy in a broader population. Nonetheless, the results are of interest since they are a true representation of the program effectiveness in real clients in the weight loss centers.
In conclusion, the 5 & 2 & 2 Plan administered at MWCCs appeared to be well-tolerated and resulted in clinically meaningful weight loss in a majority of the study population, which consisted primarily of extremely obese individuals. Concomitant improvements in cardiometabolic risk factors were also observed. Based on these results, the 5 & 2 & 2 Plan represents a viable first line treatment option for individuals with extreme obesity and may have utility prior to advocating more intensive treatments, such as pharmacotherapy or bariatric surgery. Given the need for an accompanying lifestyle intervention, this program could also be an effective pairing for use with other treatment modalities.