Based on Decades of Research

Efficacy of MetPro:
Metabolic Advantages of a
Multi-Disciplinary Approach to Weight Loss

Executive Summary

This report analyzes some of the most common and well-researched approaches to weight loss, including: calorie restriction, carbohydrate restriction, exercise, and nutritional periodization. The study compares these individual methods in creating long-term body composition with the multi-disciplinary approach implemented by Metabolic Profiling (MetPro). 

While each individual method shows some measure of efficacy, they do not produce long-term success when applied in isolation. Instead, by strategically combining these methods in a multi-disciplinary approach to weight loss, MetPro consistently produces superior long-term results.

Introduction to MetPro

Metabolic Profiling (MetPro) began as a mathematical model for increasing performance through periodized sports nutrition. Its original design was to identify when and how much to adjust total energy intake. As sports specific bodyweight goals were introduced, the algorithm grew more sophisticated. Today MetPro predicts bodyweight changes based on energy intake and energy expenditure. Furthermore, to our knowledge, it’s the first algorithm to use an individual’s data to forecast the likely degree of metabolic adaptation with each adjustment. This metabolic modeling allows users to establish a baseline in as little as 72 hours and begin making nutritional adjustments.

Today MetPro is frequently applied to weight loss. The intention of this article is to review current research on the four primary interventions MetPro has identified as most influential to weight loss outcomes.

1. Calorie restriction
2. Carbohydrate restriction
3. Exercise
4. Nutritional Periodization 

Each of these methods show credible records of weight loss. As will be demonstrated, there remains some debate between researchers as to the degree of efficacy within each modality. The goal of this research is to review many overlapping studies and establish an optimal application of each method. As will become evident, application of the following modalities in isolation produces sub-optimal results, especially long-term. There is overwhelming evidence that weight loss maintenance is especially problematic and deserves further research and consideration. 

Based on the research at MetPro there is a strong reason for optimism. The MetPro multi-disciplinary approach to weight loss consistently produces superior long-term results by combining the best of each intervention. MetPro’s unique forecasting analytics and nutritional periodization allows for defensible improvements in metabolic performance where less holistic approaches fail. 

What is MetPro

Metabolic Profiling is a multi-disciplinary approach that uses the four modalities researched within this article: calorie restriction, carbohydrate restriction, exercise, and nutritional periodization. It is applied under the direction of experienced coaches, registered dietitians, and exercise physiologists. Metabolic Profiling employs rigorous data analytics (weight tracking, meal tracking, exercise logging, adherence statistics, and recovery reporting) and includes behavioral modification with advanced food planning tactics whenever possible. Metabolic Profiling does not endorse nutritional supplements, premade meals, or food replacements, nor does it recommend any particular supplement or brand over another.

Acknowledgements of the Human Element

While the goal of this research is to establish credibility of methodology both individually and in concert with one another, it must be acknowledged that behaviors, habits, and motivation are inextricably tied to outcomes. Longer studies with less oversight are harder to quantify. This combined with the difference in protocols, parameters, and controls within each study make precise comparisons difficult. As an example, a study that requires a greater level of restriction may produce superior outcomes initially. However, such protocols are often impractical for daily living and are not anticipated to be sustainable. Meanwhile other interventions producing modest outcomes might be easily adopted long term. Therefore, discernment is needed when comparing research. It is our effort to highlight the most relevant research while presenting all sides, which includes sustainability.

It is further acknowledged that MetPro is a paid program that includes daily monitoring and interaction with qualified experts. While most weight loss trials include an element of oversight, the degree and frequency of interactions range dramatically. Some are short, controlled inpatient studies that produce high-quality data but often translate poorly to real world settings. Other longer-term studies may include little interaction between the participants and those overseeing the research for months at a time. Finally, the cost associated with a high level of interaction between experts and participants make long term studies of this kind uncommon. 

Despite these challenges, the analysis contained within represents a multi-year collection of outcomes from hundreds of MetPro participants representing a diverse population of real-world men and women of varying age, athletic ability, and motivations. Additionally, the directors at MetPro aim to maintain a balance between the total outcomes and sustainability on a person-by-person basis. Finally, program length and adherence are both positively and negatively associated with economics, a factor not present in most research. 

In consideration of the aforementioned factors, we are presenting our findings in tandem with a broad review of published research that considers each of the four interventions that MetPro employs. Included in each section is an example of our own outcomes and how the MetPro multi-disciplinary approach aligns and compares favorably with current research.

Methods, Criteria, and Inclusion

Participants included in the analysis were overweight or obese (BMI ≥ 25) adults age 18-75. To be included in the retrospective analysis they must have been enrolled in MetPro for at least 365 days. A quarterly sample of data was taken to ensure engagement. Participants were included regardless of adherence to most accurately represent average outcomes. Participants without analytics (data tracking) during quarterly samplings, or who selected muscular development in place of weight loss as their primary goal were excluded. 

Overview of Modalities

Calorie restriction can be introduced in many ways and offers flexibility between approaches. Most research agrees that total energy restriction is more influential than the method of restriction itself. However, not all methods of calorie restriction optimally support exercise, a component proven critical to maintenance of weight loss. Additionally, not all or methods of calorie restriction produce equal maintenance of fat-free mass (FFM). All methods of calorie restriction if sustained eventually produce metabolic adaptation. In an analysis involving obese women, MetPro is at least as effective as calorie restriction, but delivers superior average weight loss and weight loss maintenance.

Carbohydrate restriction is less flexible than calorie restriction with most research showing unremarkable results when only minor carbohydrate restriction is applied. However, carbohydrate restriction of significant magnitude has been shown to deliver greater total body weight loss. Much of this can be accounted for by changes in water balance. Researchers are divided on the degree of benefits of carbohydrate restriction beyond that of calorie restriction. However, some studies have demonstrated greater appetite control along with greater total body weight loss. Carbohydrate restriction of significant magnitude can adversely affect athletic performance; result in more adaptation to carbohydrate restriction than calorie restriction; and lead to carbohydrate sensitivity. If sustained, carbohydrate restriction eventually produces metabolic adaptation. In an analysis involving obese men, MetPro produces results in line with carbohydrate restriction but with less carbohydrate sensitivity and metabolic adaptation.

Exercise has been identified as a crucial part of weight loss maintenance. A large analysis of many studies found exercise present in 88% of weight loss studies deemed successful. Research has shown there is a link between preserving lean muscle mass and combating metabolic adaptation. Aerobic exercise contributes to weight loss through increased energy expenditure while resistance training preserves or builds lean muscle mass and improves body composition. Hybrid training may play a role in time efficient training strategy. Recent studies suggest results can be optimized by considering body type and goals. Exercise increases total energy expenditure and reduces the degree of dietary restriction required for weight loss. While exercise may not eliminate metabolic adaptation, it will reduce its severity. In an analysis involving physically active MetPro participants, those exercising 3-4x/week lost 34% more weight than those exercising only 1-2x/week. 

Nutritional Periodization is the often-missed link in combating metabolic adaptation. Metabolic adaptation is our body’s way of adjusting its metabolism to what we eat in its efforts towards homeostasis. Since we can’t survive a state of perpetual weight loss, the body has many complex hormonal and physiological methods of defending against weight loss. One such method called adaptive thermogenesis (AT) is becoming better understood by researchers today. What’s clear is the link between energy restriction and our body mounting a defense against weight loss. However, there is reason for optimism. There are studied examples of individuals regaining baseline resting metabolic rate (RMR) and even improving upon it through calculated periods of refeeding. At MetPro we consider this a critical form of nutritional periodization that we’ve made a part of every client’s protocol with impressive results. In our largest analysis of MetPro participants, an average weight loss of approximately 10% body weight was observed at 6 months. However, at the end of one year, weight regain had not occurred. In fact, during the time typically associated with weight regain, there was an additional weight loss to 14% among the top 25% of participants.

Current research indicates that under favorable conditions, individuals attempting to lose weight will see an initial period of weight loss lasting 10-20 weeks. This is followed by a period of weight regain over 5-8 months (or beyond). Some studies show 33% – 50% weight regain among successful interventions, of which most included diet restriction, behavioral modification, and exercise combined. Meanwhile, well over 66% weight regain is shown in others.1

Calorie Restriction Effects on Body Composition

Energy reduction is the most established method of weight loss and may be required in most cases for significant weight loss to occur. However, weight regain after an initial intervention period is consistent across the research literature for calorie restriction. 

Benchmark Clinical Studies

The benefits and drawbacks associated with calorie restriction have been well documented over the years. The short-term benefit of calorie restriction is fat loss. However, the drawback is the inability to sustain that fat loss over the long term. Here are examples of recent studies: 

• In a clinical trial evaluating the treatment of obesity through calorie restriction, researchers observed an average of 8.5 kg loss in participants at 5 months while following a 1,200 kcal/day diet. According to the population’s median caloric intake at the time of the study, participants would have been reducing their daily intake by about 1000 calories. Participants maintained approximately two-thirds of the weight loss a year after the program ended.2
• A comprehensive analysis observed that though many studies have been able to induce weight loss, maintenance of weight loss has been shown to be much more difficult.3
• A handful of studies demonstrate that while calorie restriction is a valid method, it is flawed without being combined into a multi-disciplinary approach. For example, one randomized trial included two groups of obese women; one group was counseled using fat restriction, the other using calorie restriction. After 6 months, weight loss averaged 10.2 lbs in the fat restriction group and 8.1 lbs in the calorie restriction group. Over the next 12 months, despite continued intervention, the average weight returned to baseline levels in both groups.4
• A systematic review evaluating the ability to maintain any lost weight after interventions found that overall, the mean percentage of weight loss maintenance was 54%, and maintenance did not differ significantly between interventions of 5-10% vs. >10% weight loss across all restriction methods.5

In addition to sustained fat loss, an additional drawback to calorie restriction is a corresponding drop in resting metabolic rate (RMR). The results of one study indicate that RMR decreased after calorie restriction beyond expected values based on fat-free mass (FFM). In other words, calorie restriction can reduce the metabolic rate further than what is expected from weight loss alone. A study of 48 non-obese participants showed that resting metabolic rate was decreased at 12 weeks after starting caloric restriction with no changes to exercise.6 

More recently we’ve learned that adaptation to intake restriction can take place much faster than previously thought. In one study, it was observed that adaptive thermogenesis took place within 3 days of semi-starvation, and is independent of changes in body weight and fat mass.7 

Finally, data show that adhering to calorie restrictions over the long term can be difficult. Evidence suggests that in some individuals, genetic and environmental factors interact to result in obesity. One study sheds some light on the numerous pathways and hormones (i.e., leptin, ghrelin, and insulin) that play a role in appetite, and therefore weight stabilization.8  

While calorie restriction is a well-established method of weight loss, data consistently show weight regain after an initial intervention period. The factors articulated in the studies explain part of the challenges inherent in weight loss and weight maintenance thereafter. While a calorie restriction strategy has well-documented weight loss results, calorie restriction has deleterious effects on RMR, contributing to weight regain. Additional physiological factors also impact weight loss maintenance. The pancreatic hormone insulin, gut hormones like ghrelin, cytokines like leptin, and even parts of the brain (including the hypothalamus and brainstem) play a role in regulating energy homeostasis and appetite. All these factors contribute to both behavioral and physiological difficulties maintaining weight loss.

MetPro Data

A retrospective analysis included a population of 57 obese females 27 to 65 years of age with a BMI ≥ 30 (median weight of 93.17 kg or 205.40 lbs). Participants were coached in the MetPro multi-disciplinary approach for over one year. Participants had to update their body weight, macronutrient intake, fitness activity type, and fitness duration for a year to qualify for analysis. Comparisons were made at intervals of 3 months, 6 months, and 1 year. Weight loss percentages were calculated using total weight loss relative to initial weight prior to beginning MetPro. 

At 6 months, participants’ median weight decreased by 9.06 kg (19.97 lbs), or just under 10% of body weight. 25% of the participants lost 13.1% of their body weight during this intervention period. (Generally, the minimum weight loss percentage considered an effective intervention is 5%.) 75% of all obese women lost more than 5% of their body weight within the first 6 months. 

At the end of one year, there was a further weight loss of 10.16 kg (22.39 lbs). While median weight loss stayed constant at 9.3%, 25% lost more than 16.8% of their body’s original weight during the time period. 

Notably, at the end of one year, during the time period typically associated with weight regain, weight loss continued. 

Even studies considered to be successful indicate that when a population is evaluated several months after an intervention there is approximately 54% weight regain.9 The data show the superiority of the MetPro weight loss methodology when compared to the common calorie restriction method.

Carbohydrate Restriction Effects on Body Composition

The benefits and drawbacks associated with carbohydrate restriction have been well documented over the last couple of decades. Carbohydrate restriction results in faster initial weight loss, and may help stabilize appetite and reduce sugar cravings. However, when accounting for water balance and increased sensitivity to carbohydrates, the longer-term benefits become less clear. Increased carbohydrate sensitivity can be a trigger leading to yo-yo dieting. Calculated carbohydrate restriction can positively impact outcomes and physiology in many cases, but shouldn’t be applied without considering long-term weight loss maintenance or energy intake requirements of athletic performance.

Benchmark Clinical Studies

The data from these studies illuminate several key findings. 

• Carbohydrate restriction results in greater total weight loss than calorie restriction alone. 
• The difference between total weight loss with carbohydrate restriction compared to calorie restriction alone is dominantly related to reduced water weight (water balance). 
• Though appetite is subjective, carbohydrate restriction correlates positively to appetite control in most studies. 
• Carbohydrate restriction may result in more adaptation to carbohydrate restriction than calorie restriction alone. 
• Carbohydrate restriction of significant magnitude results in decreased muscle glycogen and may impair athletic performance.

Does carbohydrate restriction have a disproportionate effect on weight loss relative to total caloric restriction? In one randomized study comparing very low carbohydrate diets with calorie-restricted diets, researchers demonstrated that restricting carbohydrates resulted in greater weight loss than calorie restriction alone.10 

Another study observed that reductions in food cravings occurred within four weeks of a carbohydrate-restricted diet, with women experiencing a greater reduction in sweet cravings than men.11 However in another study, significant differences in weight loss between high (45%) and low (15%) carb groups were not observed.12

Interestingly, a short inpatient study–which the authors consider more controlled than outpatient models–resulted in more body fat loss with dietary fat restriction even though total weight loss was greater in the reduced carbohydrate group.13

A similar outcome was observed in a study comparing carbohydrate-restricted and reduced-fat groups. Of the two, the carbohydrate-restricted group experienced greater total weight loss. The reduced-fat group experienced less adaptation to carbohydrate and fat restriction, thus leading to greater fat loss than the reduced carbohydrate group.14 

Another study compared obesity treatments using carbohydrate-containing and carbohydrate-restricted hypocaloric diets. Researchers observed a significant decrease in endurance during cycle-exercise at approximately 75% VO2 max in the carbohydrate-restricted group that was not observed in the low-calorie group. Pre-exercise muscle glycogen did not change significantly in the low–calorie group but decreased by approximately 50% in the carbohydrate-restricted group. The results indicate that adding significant carbohydrate restriction to a hypocaloric diet impairs performance.15

MetPro Data

A retrospective analysis included a population of 112 overweight and obese males 29 to 69 years of age with a BMI ≥30 (median weight of 111.45 kg or 245.71 lbs). Participants were coached in the MetPro multi-disciplinary approach for over one year. Participants had to update their body weight, macronutrient intake, fitness activity type, and fitness duration for a year to qualify for analysis. Comparisons were made at intervals of 6 months and 1 year relative to the program start date. Participants on MetPro lost weight by shifting between periods of higher and lower carbohydrate intake, and periods of higher and moderate-low calorie intake, while prioritizing exercise and physical activity.

At 6 months, average weight loss was 10.43 kg (22.99 lbs), approximately 10% of the average starting body weight. At the end of one year, the average weight loss percentage remained constant. Effectively, during the time period typically associated with weight regain, weight remained consistent.

Exercise Effects on Body Composition

Data show that exercise plays a major role in the maintenance of weight loss, fights metabolic adaptation, and in the case of resistance training, preserves lean mass. Since weight maintenance remains the most challenging piece of the weight loss equation, it stands to reason that a comprehensive approach to weight loss should include exercise planning from the beginning. Research indicates there is much room for individualized exercise based on body type, goals, and preferences. MetPro data indicate that structuring exercise around nutritional periodization, body type, and goals enhance compliance and consistency. Accountability and behavioral modification has been shown to improve outcomes across both research and literature. 

Benchmark Clinical Studies 

One 10-month research trial demonstrated that aerobic exercise, without energy restriction, provided clinically-meaningful weight loss in overweight and obese men and women when expending 600 kcalories per session, 5 days per week.16 

Another trial involving young overweight men and women demonstrated exercise ability to prevent weight gain in women and resulted in weight loss in men. This 16-month trial showed a statistically-significant weight difference between the exercise groups and the non-exercise control groups for both men and women, despite women remaining only weight-stable over the trial period. In both trials (men and women in the first, and men only in the second) the weight loss was almost entirely from body fat.17 

A meta-analysis that considered 25 years of weight loss research highlighted a central theme: diet (or, diet plus exercise) is a significantly more effective intervention for weight loss when compared to exercise alone. Of note, the difference between diet plus exercise versus diet alone becomes most significant for weight loss maintenance. This reinforces the general consensus that exercise is critical for the maintenance of weight loss.18 

While researchers agree the type of exercise performed can impact weight loss, there is no consensus on exercise’s effect on resting metabolic rate (RMR) while under the effects of calorie restriction. Aerobic exercise is consistently associated with fat mass (FM) losses but has limited effect on maintenance of fat free mass (FFM). Aerobics (interval or steady state) of sufficient magnitude trigger an increase in resting energy expenditure (REE) for at least 22 hours based on a study of elevated REE following high-intensity exercise. However, during this study, energy balance was not hypocaloric like it would be while dieting, and REE was not increased following 8 weeks of aerobic training when exercise was restrained for 60 hours.19 

Consensus has not been reached for studies combining aerobics and diet-induced weight loss. Some studies show a sparing effect on Resting Energy Expenditure (REE) while others do not. In a study of exercise, metabolism, and severe caloric restriction, researchers observed that 30 minutes daily at 60% VO2 max reversed the decrease in RMR while consuming 500 kcal/day. However, the test was only conducted on 5 obese individuals and was of relatively short duration (4 weeks).20 

In this larger study of 65 moderately-obese participants, researchers found that over 8 weeks of calorie restriction and training, both groups (aerobic training and resistance training) lost a similar amount of weight. However, the strength-training group lost significantly less FFM compared to non-exercise and aerobics-only groups. The authors concluded that strength training significantly reduced the loss of FFM during dieting but both groups still experienced a similar decline in RMR.21 

Meanwhile, in a study of body composition and REE, researchers observed women, 48 African-American and 46 European-American who were premenopausal and overweight as they underwent weight loss to a BMI <25. They found that the aerobic training and non-training groups decreased in REE with similar weight loss effects, while the resistance training group did not.22 

While research has consistently shown that resistance training is effective for maintaining or increasing FFM, neither resistance training nor aerobics have been constantly shown to negate the impact dieting has on REE. This impact has only been demonstrated in some studies, while not in others, as seen previously. 

Furthermore, in 2001 (updated in 2009) the ACSM (American College of Sports Medicine) published a position, adopting the stance that resistance training does not seem to be an effective means for weight loss. Instead, resistance training is associated with numerous other health benefits including decreases in many chronic disease risk factors and increases in fat-free mass, and decreases in fat mass. 

In regards to moderate-intensity physical activity (PA), the ACSM suggests that 150-250 minutes/week (with an energy equivalent of 1,200-2,000 kcal/week) seems sufficient to prevent weight gain greater than 3% in most adults and may result in modest weight loss. The ACSM recommends adults participate in at least 150 minutes/week of moderate-intensity PA to prevent significant weight gain and reduce associated chronic disease risk factors. The organization noted its position was also endorsed by the ADA (American Dietetic Association).23 

In a New England Journal of Medicine study, 141 obese older adults completed a trial that showed that lean mass decreased less in the combination (resistance and aerobics) and the resistance-only group compared to the aerobics-only group while losing weight. This study was of particular interest because it focused on one of the most at-risk demographics for losing muscle while losing weight (obese older adults). It is reasonable to conclude that if the efficacy of resistance training can be established within this group, outcomes would be even better among younger populations.24 

This assumption was formally observed in the meta-analysis of resistance training in healthy adult males. Researchers identified 1,927 participants from 111 articles (158 groups) published between 1973 to 2018. The results of the overall effects on muscle mass (FFM + LMM + SMM) before and after the resistance training regimen showed significant improvement between pre and post-test.25 

Even studies focusing on older women demonstrate the efficacy of resistance training for increased strength, due at least in part to muscle hypertrophy. It can be concluded that resistance training is an effective strategy for muscle preservation or development in adults across age and gender.26 

Depending on an individual’s priority, data indicates a combination of aerobic and resistance training may be the most effective to achieve weight loss. In a larger study conducted in coordination with Duke University Medical Center and East Carolina University, researchers separated 119 sedentary overweight or obese adults into resistance training (RT), aerobic training (AT), and a combination of aerobic + resistance (AT/RT) for an 8-month exercise protocol. Of note, the RT exercise prescription represented the upper limit of the amount recommended by the American College of Sports Medicine in terms of sessions per week and sets per session. Findings include: 

• The RT group induced significant gains in lean body mass and strength, but a substantial amount of RT alone did not reduce body mass or fat mass. 
• The AT and AT/RT groups reduced total body mass and fat mass more than RT, but they were not different from each other.
• The RT and AT/RT groups increased lean body mass more than AT.
• Though requiring double the time commitment, a program of combined AT and RT did not result in significantly more fat mass or body mass reductions over AT alone. However, having the benefit of both modes of exercise allowed AT/RT to decrease body fat percent significantly more than either AT or RT, due to decreased fat mass combined with increased lean body mass.
• Waist circumference decreased significantly more with AT/RT than AT or RT. However, nearly twice as much time was spent in training for the AT/RT group.

Ultimately, the study concludes that balancing time commitments against health benefits, it appears that AT is the optimal mode of exercise for reducing fat mass and body mass, while a program including RT is needed for increasing lean mass.27 

While a combination of aerobics + resistance training may be the most effective activity for fat loss, there might be an alternative for young healthy persons of average (or better) fitness. In the article Metabolic adaptations to Short-term High-Intensity Interval Training; A little Pain for a Lot of Gain?, researchers found several potent and time-efficient metabolic adaptations in response to high-intensity interval training (HIIT). These adaptations are usually associated with traditional endurance training that requires much greater volume/time. As suggested in the article name, these efficiencies come with some pain. For some people, this method will be too intense to start with. But for those able to accommodate the intensity, the adaptation will be a hybrid between resistance training and endurance training with more characteristics slanted towards endurance training.28 

Researchers found that a hybrid of the two modalities can be achieved using high-intensity intermittent exercise (HIIE). HIIE has been shown to significantly increase both aerobic and anaerobic fitness. Preliminary evidence suggests that HIIE can result in modest reductions in subcutaneous and abdominal body fat in young normal-weight and slightly-overweight males and females.29 

Lastly, there is additional evidence based on the Heath-Carter somatotype assessment that has led some researchers to pursue an approach to exercise prescription based on body type.30 While evidence supporting a particular formula for each body type needs further research, some conclusive studies hint at a strong correlation between body type and performance outcome. For example, one study found a positive correlation between three rep max exercises with an individual’s mesomorphy.31 Researchers found in another study the difference between somatotypes in aerobic trainability hinted at the need for further individualization between body types.32 

Collectively, these studies demonstrate that there is a link between preserving FFM and resisting declines in RMR. However, a component of adaptive thermogenesis appears to persist through the maintenance of FFM which may explain why not all research is in agreement. Still, exercise is positively linked to weight loss outcomes. Aerobics are especially linked to weight loss and fat loss but not effective for preserving muscle mass. Resistance training is especially linked to increasing or preserving muscle mass but not associated with increased weight loss. Hybrid exercise may have a role in time optimization for healthy active individuals who can tolerate it well. And, exercise prescription can be optimized when considering somatotype and goals. Exercise is strongly correlated to the maintenance of weight loss.

MetPro Data

A retrospective analysis compared a population of 203 overweight and obese adult females and males with a BMI ≥ 25. 57 participants exercised 1-2x per week. 146 participants exercised 3x per week or more. Participants were coached in the MetPro multi-disciplinary approach for over one year. To qualify for the analysis participants had to be actively engaged (data tracking) for one year. 

At the end of one-year, the group exercising 3-4x/week lost 34% more median weight relative to the group that exercised less frequently. While both participated in exercise and had favorable outcomes, the increased weight loss in the group with more training volume confirms the impact of exercise and its correlation to dose. Moreover, the MetPro multi-disciplinary approach produces a body percentage weight loss of 10.48%, which doubles the industry’s generally-accepted success rate of ≥ 5% weight loss.33

Nutritional Periodization and Metabolic Adaptation Effects on Body Composition

Researchers have recently increased their attention to the effects of nutritional periodization, especially as metabolic research has increased. While the term “nutritional periodization” might not be as recognizable as keto or calorie counting, its core tenets are found in everything from sports nutrition to intermittent fasting. 

In sports nutrition, athletes plan ahead and alter food consumption based on the work required. Bodybuilders are known for making drastic additions or subtractions based on bulking and cutting cycles that can last weeks or months at a time. Many popular diets advocate for certain days of the week to be higher or lower intake. Some variations of intermittent fasting promote complete abstinence of fuel on certain days or during certain hours. 

Benchmark Clinical Studies

In one study, 1,429 participants from the National Weight Control Registry helped examine whether long-term weight loss maintenance is enhanced by maintaining the same diet regimen across the week and year or by dieting more strictly on weekdays than at other times. The results were a linear relationship between dieting consistency and smaller weight gains. Participants who reported a consistent diet across the week were 1.5x more likely to maintain their weight. This study indicates that from a behavioral standpoint, consistency is positively correlated with weight-loss maintenance.34 

In a more granular evaluation of active dieting, 150 overweight and obese non-smokers were assigned to one of two groups. The first group was given intermittent calorie restriction, standardized as the “5:2 diet” (5 days without energy restriction and 2 days with 75% deficit); the second group was given continuous calorie restriction. Both groups used a total net energy deficit of 20%. At the follow-up assessment the results were similar, which could indicate that total restriction was more influential than timing.35 

In The role of intermittent fasting and meal timing in weight management and metabolic health, researchers evaluated several studies. The analysis considered multiple facets of intermittent fasting, such as fasts of various lengths with the defining characteristic being the confinement of energy restriction to a specified window (whether 16 hours each day, every other day, or just 2 days each week). The analysis noted that intermittent fasting can elicit reductions in body mass which appear broadly comparable to standard daily energy restriction.36 

Studies suggest results are similar between approaches to energy restriction. This raises the question: does the method matter to achieve energy deficit? Indeed, the difficulty is in maintaining weight loss. 

In a study evaluating models of energy homeostasis, the energy expenditure (EE) in 17 obese inpatient subjects were studied at 3 intervals: at their usual weight, after 10% weight loss, and again after 20% weight loss (liquid diet). The results at 10% weight loss showed that resting (REE) and non-resting (nREE) energy expenditure were significantly below those predicted on the basis of the amount and composition of weight loss. This study indicates that dieters can expect metabolic slowing beyond what can be accounted for by changes in body mass. Following an additional 10% weight loss (total of 20%) further declines in REE were consistent with a threshold model (no change with further weight loss) while the disproportionate decline in non-resting energy (nREE) was largely reflective of the degree of weight loss. The inference is that REE will only drop so far (threshold model) but further adaptive efficiencies take place in physical activity following greater weight loss. In other words: the body finds a way to be more efficient and burn less energy for activities under these conditions.37 

Approaching the question from a slightly different angle, another group of researchers embarked on a detailed breakdown of the process of adaptive thermogenesis. The adaptive thermogenesis process refers to changes in resting and non-resting energy expenditure that takes place independent of weight loss and body composition. Again, this specifically refers to the sum of components that contribute to the “unexplained” adaptation to energy restriction that cannot be accounted for by weight loss, fat loss, or muscle. The data relates adaptive thermogenesis to two different “set points” with a “settling” between them. In early weight loss, the first “set” is related to depleted glycogen stores when adaptive thermogenesis begins to meet the brain’s energy needs. Then, during maintenance of reduced weight, the second “set” relates to decreased leptin levels keeping energy expenditure low to prevent triglyceride stores from getting too low, which is a risk to some basic biological functions such as reproduction.38 

If these concepts around metabolic adaptation are to be accepted, a clear goal is to reduce body weight with less adaptation, using all sources within our control. 

In a study focused on calorie restriction and its effect on resting metabolic rate, dieters restricting 25% energy were compared against other groups, one of which was half calorie restriction and half exercise expenditure (12.5% calorie restriction + 12.5% exercise expenditure). RMR measurements were collected at the start of the study, at 3 months, and at 6 months. Researchers concluded that RMR adapted or decreased beyond values expected from changes in weight and body composition as a result of energy deficit through food (25% restriction) after 3 months. This is consistent with the aforementioned studies. Additionally, RMR decreased beyond expected values for the half and half group (12.5% calorie restriction + 12.5% exercise expenditure) group at 6 months. This delta between the two groups of 41 kcals/day and up to 3 additional months potentially leaves the door open to metabolic optimization between approaches, while recognizing that even while optimized, a decrease in RMR based on energy deficit is expected.39 

The findings of the previous study are consistent with the observations in a meta-analysis of diet and diet-plus-exercise programs on resting metabolic rate. Studies indicated, contrary to what is reported in narrative reviews, RMR decreased significantly with both diet and diet + exercise programs. The drop with diet-only was significantly greater than that with diet + exercise. In conclusion, the addition of exercise to dietary restriction appeared to prevent some of the decrease in RMR, at least in this study that observed premenopausal women.40 

Though varied intakes affect RMR, there is some basis to be optimistic that metabolic recovery can occur after a period of dieting. One study evaluated a female physique athlete’s RMR baseline while at 20.3% body fat and after two competition prep cycles that reduced body fat to 12.2% and then 11.6%. Her RMR decreased from 1,345 kcal/day to a low value of 1,119 kcal/day between competitions. But by the end of recovery, RMR increased to 1,435 kcal/day which was above baseline values. 

This study indicates it is possible–at least in the case of an exceptional athlete–to recover RMR or even improve it. Of special note in this study, RMR decreased by over 200 kcal/day, but this occurred without any loss of FFM. In fact, when the athlete’s RMR was at its lowest, her FFM was actually 1.2 kg higher relative to pre-diet levels. This would suggest that the best single predictor of RMR in female athletes is intake. In other words, a person’s total fuel consumption may be more influential than total FFM in some circumstances.41 This study’s findings aligned with another study of female endurance athletes which concluded that energy intake was the best predictor of RMR in female endurance athletes.42 

Broadening this perspective, the following study offered the viewpoint that homeostatic regulation of body weight is more effective when energy intake and expenditure are both high (high energy flux), implying that low energy flux should predict weight gain. Interestingly, results indicated that low energy flux (i.e., low levels of habitual caloric intake coupled with low levels of energy expenditure) predicted future body fat gain. There was a predictive inverse relation between energy flux and future body fat gain, and an association between energy flux and RMR. 

The researchers suggested that weight loss might be more attainable via high physical activity that is coupled with high energy intake, rather than subscription to commonly-prescribed low-calorie diets.43 While there may be practical limits to this theory, it aligns with the conclusion that was again demonstrated in a study of young adult men which illustrates that increased intake (or overfeeding) can have a significant impact on total daily energy expenditure (TDEE) particularly when paired with exercise or increased nREE.44 

It’s difficult to look at the totality of research and conclude that weight loss could be consistently and significantly produced in populations without energy restriction. However, it also can’t be ignored that energy restriction has deleterious effects on RMR and weight regulating hormones (such as leptin and ghrelin). Meanwhile energy increases are often associated with reversals or improvements in RMR. 

Studies suggest that dietary interventions should be individualized around the most important factors, including: 

• Include protein sufficient to maintain FFM, and increase FFM in ideal circumstances.
• Ensure energy is sufficient for maintaining nREE, and in ideal circumstances, increase activity.
• Restrictions should not exceed what’s necessary for weight loss or fat loss. Research indicates this threshold has significant individual variance and is affected by: heredity, somatotype, current and previous adaptive thermogenesis, FFM, nREE (or NEAT), leptin levels, and exercise.
• Ongoing interventions should include periods of increased energy intake (refeeding) in conjunction with increased exercise to defend against metabolic adaptation.
• Include resistance training to maintain or minimize loss of FFM.
• Include aerobic exercise to increase total energy expenditure (TEE) and reduce the magnitude of energy restriction required for weight loss or weight maintenance (since dietary restriction is strongly correlated to metabolic adaptation).

Exercise appears to broadly be correlated with dose. More specifically, increased aerobics contribute to acute and short-term increases in energy expenditure while resistance training is associated with maintenance of FFM and can preserve RMR values. Still, it appears there remains a threshold response to adaptive thermogenesis that resists RMR maintenance even through the persistence of FFM, while the nREE component of metabolic adaptation remains influenced by FFM. 

Increased energy intake (or refeeding) is associated with increased REE and TEE especially when paired with exercise. In addition, high energy intake combined with high energy expenditure has been positively linked to homeostatic maintenance when compared to low intake and low activity. Combined, this evidence provides a strong argument for nutritional periodization and planned metabolic recovery times designed to attenuate periods of weight loss (particularly extended periods) and especially for post-weight-loss maintenance. 

Combined, data in these studies show that weight loss plans work best when they support an active, and when possible, athletic lifestyle. Crash dieting should be avoided. Nutritional periodization–specifically, periods of calculated food increase combined with greater energy expenditure–can have a powerful impact on progress and long-term success when properly implemented.

MetPro Data

A retrospective analysis compared a population of 240 overweight and obese adult females and males (128 females and 112 males) 25 to 75 years of age with a BMI ≥ 25. Participants were coached in the MetPro multi-disciplinary approach for over one year. To qualify for the analysis participants had to be actively engaged (data tracking) for one year.

After 6 months, the average weight loss was 9.07 kg (19.99 lbs) or approximately 10% body weight. At the end of one year, weight regain had not occurred. In fact, during the time period typically associated with weight regain, data show an additional weight loss to 14% among the top 25% of participants. Additionally, the interquartile range between results increases as time increases. Outcomes among the middle 50% increases from 4% at 3 months, to 6% at 6 months, and finally expands to 10% at 12 months. 

Most diet interventions result in an initial period of weight loss typically lasting 10-20 weeks. However, this period is followed by a period of weight regain over 5-8 months (or greater). Some studies show ranges of 33% – 50% weight regain in optimistic cases, and well over 66% regain in others.1 Even when evaluating the efficacy of several “big name” programs for cardiac health, researchers reinforced a key point: the healthiest diet is one that is behaviorally sustainable and results in sustained weight loss.45

Conclusion

Well-researched weight loss strategies include calorie restriction, carbohydrate restriction, exercise, and nutritional periodization. While these strategies are commonly implemented, their efficacy is limited when used independently of one another or without planning. While isolated weight-loss strategies can result in some weight loss, it is short-lived, lasting only a few months. An Initial period of weight loss is invariably followed by significant weight regain over subsequent months. 

Comparatively, the multi-disciplinary approach of MetPro has been proven to consistently achieve long-term weight loss among overweight and obese adult females and males. Data show that MetPro participants experience sustained weight loss up to one year after beginning interventions. The combined strategies in the MetPro metabolic profiling method provide superior and sustained results for weight loss.

Conclusion

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