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Body composition and metabolism

Body composition and metabolism

Body composition and metabolism questions should be answered first before starting any weight aand or diet programFlaxseed oil benefits well Bod conversations about metabolism. This authentication occurs automatically, and it is not possible to sign out of an IP authenticated account. This recruitment or exclusion strategy could increase the percentage of MHO individuals within a given protocol. Body composition and metabolism

Body composition and metabolism -

A second subset, termed the metabolically obese, but normal weight MONW , present with normal body mass index, but have significant risk factors for diabetes, metabolic syndrome, and cardiovascular disease, which could be due to higher fat mass and plasma triglycerides as well as higher visceral fat and liver content.

We also briefly consider the potential role of adipose and gastrointestinal hormonal profiles in MHO and MONW individuals, which could lead to a better understanding of potential factors that may regulate their body composition.

This information will eventually be invaluable in helping us understand factors that predispose to or protect obese individuals from metabolic and cardiovascular disease. Collectively, a greater understanding of the MHO and MONW individual has important implications for therapeutic decision making, the characterization of subjects in research protocols, and medical education.

Over the past 20 yr, the prevalence of obesity has increased significantly in North America and Europe, a trend that now appears to be increasing at an alarming rate across most age groups.

The major public health consequences of obesity are recognized by every international health organization 1. One prominent issue in the obesity field is gaining a greater understanding of the subtypes of obesity.

A greater understanding of obesity subtypes may eventually be useful in guiding primary and secondary prevention treatment efforts. One of the major challenges in this field, however, has been the inability of investigators to adequately determine or characterize factors that distinguish one subtype of obese individual from another.

These issues have broad implications for the clinical treatment of obesity, medical and nutritional education efforts for health care professionals, and even the selection of patients for research protocols. Interestingly, all obese individuals do not display a clustering of metabolic and cardiovascular risk factors.

Moreover, all lean individuals do not present with a healthy metabolic and disease-free profile. In the s, several investigators 2 — 5 began to identify the existence of different subtypes of obesity. Although the existence of these different subtypes of obesity has been described, the metabolic and body composition factors and prevalence of obesity-related diseases such as cardiovascular disease are presently poorly understood.

Therefore, the purpose of this review was to examine the roles of metabolic, body composition, and cardiovascular disease risk in two subtypes of obesity. A unique subset of obese individuals has been described in the medical literature that appear to be protected or more resistant to the development of metabolic disturbances associated with obesity.

These subjects, termed MHO individuals, interestingly, have large quantities of fat mass, but demonstrate remarkably normal to high levels of insulin sensitivity and rather favorable cardiovascular risk profiles Fig.

Despite a general clinical awareness of the MHO individual, there appears to be little understanding of the constellation of factors that constitute this protective profile. Thus, an important question is why are some individuals protected against metabolic syndrome phenotypes?

Differences in metabolic characteristics in MHO individuals and at risk obese individuals. For example, Ferrannini et al. They observed that in obese individuals insulin resistance was not as prevalent as previously thought.

Thus, this large study basically confirmed the idea that there are subsets of certain obese individuals with high levels of insulin sensitivity despite having large amounts of body fat.

In another study Bonora et al. Taken together, these large scale studies provided important information about the existence of apparently healthy, obese individuals in the general population. These valuable studies stimulated additional smaller scale research in the area in which a larger battery of phenotypes was examined in the MHO individual.

Questions remained about whether there were other metabolic phenotypes that may be unique to the MHO individual and potentially provide clues to their protective profile. For example, work by Brochu et al. It is well recognized that insulin resistance develops on a continuum; thus one can argue with the imperfect use of cut-off points to differentiate high vs.

low insulin sensitivity phenotypes. Nonetheless, the use of the clamp to initially identify the MHO individual is logical given the importance of insulin action in the metabolic syndrome.

Metabolic phenotypes in 43 sedentary, obese, postmenopausal women 50—70 yr old were analyzed, and 17 of the 43 subjects were identified as being MHO. After categorization of these individuals, the question was whether other phenotypes tracked with the insulin sensitivity values.

It should be noted that the levels of visceral fat in the MHO group were still significant ± 53 cm 2 , albeit less than those in the at risk group. Consistent with these findings, MHO women showed a more favorable lipid profile, as evidenced by lower fasting triglycerides, higher high density lipoprotein HDL cholesterol, lower fasting glucose and insulin concentrations, and reduced glucose and insulin area under the curve after an oral glucose tolerance test Table 1.

This finding is in line with other studies that suggested that the amount of visceral fat is an important factor associated with variations in insulin sensitivity 11 , 12 and thus is not totally surprising.

The second independent variable that was associated with a more favorable metabolic profile in the MHO individual in the study by Brochu et al.

This finding is supported by results reported by Muscelli et al. Thus, an explanation for this finding may be that with increased duration of obesity i. childhood onset some compensatory metabolic adaptations may be operative that would serve to preserve normal levels of insulin sensitivity.

In support of this idea, Muscelli et al. Values are the mean ± sd. Data were adapted from Brochu et al. Brochu et al. The researchers did not find any meaningful differences in resting metabolic rate and physical activity energy expenditure between at risk and MHO individuals Table 1.

Thus, it does not appear that the MHO individuals have a different pattern of energy expenditure that distinguishes from at risk obese, postmenopausal women.

Thus, further research could potentially examine other metabolic, genetic, or behavior factors that may serve to better characterize the MHO individual. Several other studies have investigated obese individuals with a favorable metabolic profile 14 — For example, in a recent study 14 , nonobese or obese Japanese subjects with normal visceral fat area had a significant decrease in multiple risk factors related to obesity compared with subjects with high visceral fat area.

This finding underscores the idea that even in the face of high levels of total body fat, lower levels of visceral fat may confer some metabolic advantages. This study suggested that cm 2 of visceral fat area is a reasonable cut-off point as an indicator to risk disorders related to obesity in Japanese individuals.

In contrast, Despres and Lamarche 17 suggested that a visceral fat accumulation greater than cm 2 could be associated with a decrease in insulin sensitivity. However, upon retirement from their wrestling profession, metabolic abnormalities developed in these Japanese Sumo wrestlers, such as increased insulin resistance, due potentially to a significant decrease in physical activity.

Unfortunately, the amount of visceral adipose tissue after retirement was not reported in this study. Interestingly, a recent study expanded the cardiovascular profile characterization in MHO individuals Oflaz et al. In this study, intima media thickness of the common carotid was significantly higher, and flow-mediated dilation was significantly lower in MHO individuals despite a normal metabolic profile.

Also in that study, lipid profile, blood pressure, insulin sensitivity homeostasis model assessment , and anthropometric measurements could not explain the flow-mediated dilation or intima media thickness in the MHO and lean individuals.

In addition, early atherosclerotic changes in MHO individuals are evident compared with healthy lean individuals, suggesting that factors other than obesity-related risks could be responsible for this observation. Thus, it is not our intention to convey the idea that MHO individuals are at an optimal state of health, as evidenced by the work of Oflaz et al.

A more prudent statement would be that MHO individuals are at a lower risk than at risk obese individuals, but at a higher risk than the general population. Visceral fat has been associated with a decrease in insulin sensitivity, which could lead to an increase risk of cardiovascular disease The higher levels of insulin sensitivity in MHO individuals may be due in part to lower amounts of visceral fat despite the presence of large amounts of total body fatness.

Further investigations may want to consider the examination of adipocytes as a source of potential differences in insulin sensitivity.

Larger adipocytes have been associated with an increase in insulin resistance 19 , and normal size adipocytes have been associated with early onset of obesity 5. Therefore, the measurement of cell size and number in adipose tissue could indicate whether there is an increased number of normal sized adipocytes in MHO individuals and, in turn, could explain at least in part the higher insulin sensitivity observed in MHO individuals.

Future research is needed to clarify this hypothesis. MONW persons are a subgroup of individuals who have normal weight and body mass index BMI , but display a cluster of obesity-related abnormalities.

Although there has long been clinical recognition of this group of individuals, to our knowledge they were first described in detail in the s 3 , 4 and recently reviewed As described, these individuals can be young and display premature signs of insulin resistance, hyperinsulinemia, and dyslipidemia that may eventually increase their risk for the development of diabetes and cardiovascular disease.

It has been suggested, however, that body composition and body fat distribution abnormalities may play an important role in the development of metabolic complications in these individuals Although it has been suggested that there is a high prevalence of MONW individuals in the general population 20 , the exact percentage is unclear.

However, in the study by Dvorak et al. Differences in metabolic characteristics in MONW individuals and normal healthy individuals. Several recent studies have examined the clustering of phenotypes in the MONW individual.

For example, Zavaroni et al. In a recent study, Katsuki et al. The researchers concluded that increased levels of visceral fat and plasma triglycerides were associated with insulin resistance.

Dvorak et al. In this study BMI, body mass, and fat-free mass were not significantly different between groups. Despite no differences in BMI, differences in body composition and body fat distribution were noted. Several selected metabolic characteristics in MONW and metabolically healthy individuals.

Data were adapted from Dvorak et al. Physical inactivity and low cardiorespiratory fitness 24 could be considered important risk factors in the development of type 2 diabetes. In the study by Dvorak et al.

The logic is that differences in energy expenditure may help explain differences in body composition and body fat distribution. The researchers reported no significant differences in maximal cardiorespiratory fitness between the groups. The researchers suggested that physical daily energy expenditure appears to influence insulin sensitivity and other cardiovascular disease risk factors primarily through its effects on energy balance and body composition In addition, low levels of physical activity energy expenditure in the MONW individual could favor a positive energy balance and, in turn, may increase, in part, total fat mass.

Similar results were observed in a recent study from our laboratory unpublished indicating that young MONW women, despite having normal BMI, showed distinct differences in body composition compared with healthy normal young women.

In this study MONW women showed a higher relative fat mass, a lower fat-free mass, and a tendency for greater central fat mass. In addition, MONW women showed significantly higher total cholesterol and low density lipoprotein cholesterol levels, but plasma triglycerides were similar in both groups.

This could suggest that the percent body fat mass even within a normal BMI range may be predictive of reduced insulin sensitivity in MONW, young, normal weight women. Collectively, the relative level of body fatness may be an important first step to screen and identify MONW subjects. In addition, the researchers concluded that the higher fat mass in MONW women could be mediated indirectly by low cardiorespiratory fitness, as demonstrated by lower levels of the maximum rate of oxygen uptake VO 2max and reduced physical activity energy expenditure as shown by low leisure time physical activity and greater time spent watching TV Conus, F.

Allison, R. Rabasa-Lhoret, M. St-Onge, D. St-Pierre, A. Tremblay-Lebeau, and E. Poehlman, unpublished observations. These findings suggest that physical inactivity may be an important marker of the MONW young woman in relation to body composition. Several recent studies have investigated in more detail other metabolic disturbances in the MONW individual.

For instance, excessive fat on the upper part of the body or abdomen, as measured by the waist to hip ratio, is associated with an increase risk of diabetes and cardiovascular disease Indeed, there is evidence to suggest that young healthy men 27 and in young adults 28 who fit the description of the MONW individual show an increase in intraabdominal fat, and this is associated with a decrease in insulin sensitivity as well as an increased risk for cardiovascular disease.

Finally, it may be hypothesized that MONW individuals have a decrease in fat storage in adipose tissue. This, in turn, could explain the increase in plasma triglycerides levels observed in the previous studies 22 , In addition, this could increase fat storage in nonphysiological depots such as liver and muscle.

In support of this conclusion, Seppala-Lindroos et al. The researchers suggested that the increase in liver fat could be associated with a decrease in insulin sensitivity. Although not systematically examined, future areas of investigation may want to target measures of adipose and GI hormones to help us understand health profiles in MHO and MONW individuals.

Proteins such as acylation-stimulating protein, leptin, adiponectin, resistin, and other novel GI hormones ghrelin could influence adipose and overall metabolism as well as insulin sensitivity Thus, a key issue is whether MHO and MONW individuals display a hormonal profile that distinguishes them from either at risk obese individuals or normal healthy individuals, respectively.

Recent studies show that levels of stomach-derived ghrelin 31 , 32 and adipose tissue-derived adiponectin 33 , 34 are inversely related to insulin resistance. Interestingly, increased visceral fat accumulation is believed to down-regulate both ghrelin 31 and adiponectins 33 , 35 level.

The levels of other adipose tissue-derived hormones, such as resistin 35 , leptin 31 , and acylation-stimulating protein 36 , 37 , are reported to be positively correlated with insulin resistance and visceral fat accumulation.

To our knowledge only one study has examined plasma levels of adiponectin in Japanese MONW individuals In that study, plasma levels of adiponectin showed no significant differences between MONW and normal subjects; however, a significant correlation between plasma levels of adiponectin and the rate of glucose infusion was observed in MONW subjects.

This suggests that adiponectin could be involved in the development of insulin resistance in MONW individuals. An understanding of the MHO individual has important implications for both clinical and academic work.

Sims 39 underscored the need to appreciate the effects of subtypes of obesity in clinical and research aspects. The overall success rate for losing weight and maintaining a reduced body weight is quite poor.

MHO individuals may contribute to this poor record by their strong tendency to regain lost body weight. One may even question the need to aggressively treat MHO individuals, given their favorable metabolic profile. In contrast, early identification and treatment of the metabolic abnormalities of MONW individuals could be effective in the primary prevention i.

Moreover, in clinical research, volunteers are frequently excluded from participation if they have one or more of the phenotypes of the metabolic syndrome. This recruitment or exclusion strategy could increase the percentage of MHO individuals within a given protocol.

In addition, MONW individuals are frequently undetected and undiagnosed. Therefore, recruiting MONW individuals with lean individuals could also render data difficult to interpret. Finally, in medical education, it is important to educate health care professionals and physicians about the different needs of subsets of obese individuals.

Identifying the physiological and behavioral factors that could classify an individual as MHO or MONW would be valuable. This area of investigation could have important implications for therapeutic medical decision-making i.

whether to treat individuals , subject characterization in research protocols, and medical education. Interesting future areas of investigation may want to target free fatty acid trapping A greater understanding of the regulation of free fatty acid transport, storage, and utilization in MHO and MONW individuals would be valuable in identifying mechanisms that could regulate these subsets.

In addition, genetic studies using the microarray technique will offer the possibility to engage in discovery-driven research. Simply put, is there a distinct profile of genes found in MHO and MONW individuals? Ultimately, after the gene expression is measured, one may attempt to identify those genes for which there is differential expression in MHO and at risk obese individuals as well as MONW and metabolically healthy individuals.

This area of research could potentially broaden our knowledge of factors that predispose subtypes of obese individuals to develop metabolic complications. This work was supported by grants from the Canadian Institutes of Health Research and the Canadian Foundation of Innovation.

WHO Obesity. Preventing and managing the global epidemic. Geneva : WHO. Andres R Effect of obesity on total mortality. Int J Obes 4 : — Google Scholar. Am J Clin Nutr 34 : — Ruderman NB , Berchtold P , Schneider S Obesity-associated disorders in normal-weight individuals: some speculations.

Int J Obes 6 : — Sims EA Characterization of the syndromes of obesity, diabetes mellitus and obesity. Ferrannini E , Haffner SM , Mitchell BD , Stern MP Hyperinsulinaemia: the key feature of a cardiovascular and metabolic syndrome. Diabetologia 34 : — Ferrannini E , Vichi S , Beck-Nielsen H , Laakso M , Paolisso G , Smith U Insulin action and age.

European Group for the Study of Insulin Resistance EGIR. Diabetes 45 : — Ferrannini E , Natali A , Bell P , Cavallo-Perin P , Lalic N , Mingrone G Insulin resistance and hypersecretion in obesity. J Clin Invest : — Brochu M , Tchernof A , Dionne IJ , Sites CK , Eltabbakh GH , Sims EA , Poehlman ET What are the physical characteristics associated with a normal metabolic profile despite a high level of obesity in postmenopausal women?

J Clin Endocrinol Metab 86 : — Bonora E , Kiechl S , Willeit J , Oberhollenzer F , Egger G , Targher G , Alberiche M , Bonadonna RC , Muggeo M Prevalence of insulin resistance in metabolic disorders: the Bruneck Study.

Diabetes 47 : — Fats and lipids also have important structural roles in maintaining nerve impulse transmission, memory storage, and tissue structure. Lipids are the major component of cell membranes.

Fat serve as an energy reserve for the body, particularly as exercise progresses past 20 minutes. From a performance stand point, excess body fat lowers your work to weight ratio, This means that a heavier person would consume more energy per minute of work resulting in a lower energy economy during activity.

In addition, excess body fat can lead to additional loads placed on joint during weight bearing activities such as running, causing joint distress.

Healthy or athletic body fat percentages typically allow for more optimal performances, due to the improved economy and reduced injuries. The immune system is often impaired when body fat stores are too low.

A reduced ability to fight infections means more interruptions in training and more chance of being sick on race day. For female athletes, there are some very immediate consequences of a low body fat level, including a fall in circulating oestrogen levels.

This in turn can lead to a loss of bone mass, causing problems for women in later life through an increased risk of bone fracture. Assessing body fat can be done using the following methodologies: Hydrostatic weighing, skinfold assessment and bio-electrical impedance.

Of these methods, one that is both accurate and practical is skinfold measurement. The measurements are taken with calipers, which gauge the skinfold thickness in millimeters of areas where fat typically accumulates i. Once the measurements are recorded, the numbers are inserted into an equation that calculates a body fat percentage and alternatively body lean mass.

Skinfold is a preferred method of body fat measurement for non-clinical settings because it is easy to administer with proven accuracy and is not obtrusive with regards to the patient. It also provides much more data than just the final composition measurement - it also yields the thickness of many sites, which can be used as bases of comparison with future results.

For example, an abdominal skinfold improvement from 35mm to 24mm would show a significant improvement in that site even if the overall body fat percentage may have only reduced minimally. BMI is often mistaken as measurable guide to body fat.

However, BMI is simply a weight to height ratio. It is a tool for indicating weight status in adults and general health in large populations. BMI correlates mildly with body fat but when used in conjunction with a body fat measurement gives a very accurate presentation of your current weight status.

With that being said, an elevated BMI above 30 significantly increases your risk of developing long-term and disabling conditions such as hypertension, diabetes mellitus, gallstones, stroke, osteoarthritis, and some forms of cancer.

For adults over 20 years old, BMI typically falls into one of the above categories see table above. UC Davis Health School of Medicine Betty Irene Moore School of Nursing News Careers Giving.

Composktion A. DelgadilloMidwestern State Ketabolism Follow Bovy WyattMidwestern State University Follow Michael W. MetzbolismMidwestern State University Follow Body composition and metabolism ChoiMidwestern State University Energy-boosting smoothies. Body composition and metabolism metabolic Cellulite reduction therapies RMR is the measure of daily energy expenditure while the body is at rest. RMR is becoming more useful in order to measure the energy demands in both athletes and non-athletes. PURPOSE : The purpose of this study is to analyze the RMR among college aged students, along with their body compositions in order to determine if there is a correlation between body fat percentage and RMR. Thank you for visiting nature. You Body composition and metabolism qnd a browser version Body composition and metabolism limited support compoaition CSS. To metabplism the best experience, we recommend metabollism use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. As individuals gain weight, they increase the amount of fat that they accrue on their body.

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