Biomedical subjects

J P DeLany

Publications and source records attributed to J P DeLany.

At least 19 recordsLinked to original sources

PubMed2001

Body composition of African American and white children: a 2-year follow-up of the BAROC study.

OBJECTIVE: To evaluate the 2-year changes in body composition of white and African American boys and girls. RESEARCH METHODS AND PROCEDURES: A total of 114 boys and girls ages 12 to 14 years with equal sex and ethnic distribution between African American and white races participated in measurements of body composition using DXA, underwater weighing (densitometry), skinfold thickness, corporal diameters, circumferences, isotope dilution (H(2)(18)O), and bioelectric impedance. RESULTS: Sixty-eight of the 114 children advanced from Tanner Stages 1 and 2 to Tanner Stages 3 to 5 over a 2-year period. More than 50% of the children were in the top 15th percentile according to normative data for body mass index but not for triceps skinfold. All measures except for percentage of fat, density, and four of the six skinfolds increased significantly during the 2 years, with no differences between races, genders, or fat group. The boys who advanced in Tanner Stage reduced their percentage of fat and a number of skinfolds and increased their lean body mass, but the girls did not. The percentage of water was significantly higher in the fatter children and declined significantly over 2 years. Most children remained in the same quartile of body fat, lean body mass, and bone mineral content over 2 years. DISCUSSION: The data are consistent with the hypothesis that over 2 years, growth is the major determinant of changing body composition, with body-fat group and sexual maturation being additional variables.

Absorptiometry, Photon↗

PubMed2001

Validity of self-reported energy intake in lean and obese young women, using two nutrient databases, compared with total energy expenditure assessed by doubly labeled water.

OBJECTIVE: To compare self-reported total energy intake (TEI) estimated using two databases with total energy expenditure (TEE) measured by doubly labeled water in physically active lean and sedentary obese young women, and to compare reporting accuracy between the two subject groups. DESIGN: A cross-sectional study in which dietary intakes of women trained in diet-recording procedures were analyzed using the Minnesota Nutrition Data System (NDS; versions 2.4/6A/21, 2.6/6A/23 and 2.6/8.A/23) and Nutritionist III (N3; version 7.0) software. Reporting accuracy was determined by comparison of average TEI assessed by an 8 day estimated diet record with average TEE for the same period. RESULTS: Reported TEI differed from TEE for both groups irrespective of nutrient database (P<0.01). Measured TEE was 11.10+/-2.54 and 11.96+/-1.21 MJ for lean and obese subjects, respectively. Reported TEI, using either database, did not differ between groups. For lean women, TEI calculated by NDS was 7.66+/-1.73 MJ and by N3 was 8.44+/-1.59 MJ. Corresponding TEI for obese women were 7.46+/-2.17 MJ from NDS and 7.34+/-2.27 MJ from N3. Lean women under-reported by 23% (N3) and 30% (NDS), and obese women under-reported by 39% (N3) and 38% (NDS). Regardless of database, lean women reported higher carbohydrate intakes, and obese women reported higher total fat and individual fatty acid intakes. Higher energy intakes from mono- and polyunsaturated fatty acids were estimated by NDS than by N3 in both groups of women (P< or =0.05). CONCLUSIONS: Both physically active lean and sedentary obese women under-reported TEI regardless of database, although the magnitude of under-reporting may be influenced by the database for the lean women. SPONSORSHIP: USDA Hatch Project award (ARZT-136528-H-23-111) to LB Houtkooper and WH Howell.

Adolescent↗

PubMed2001

Relationship of dietary fat and serum cholesterol ester and phospholipid fatty acids to markers of insulin resistance in men and women with a range of glucose tolerance.

High-fat diets are associated with insulin resistance, however, this effect may vary depending on the type of fat consumed. The purpose of this study was to determine the relationship between intakes of specific dietary fatty acids (assessed by 3-day diet records and fatty acid composition of serum cholesterol esters [CEs] and phospholipids [PLs]) and glucose and insulin concentrations during an oral glucose tolerance test (OGTT). Nineteen men and 19 women completed the study. Nine subjects had type 2 diabetes or impaired glucose tolerance. Fasting insulin correlated with reported intakes of total fat (r = .50, P < .01), monounsaturated fat (r = .44, P < .01), and saturated fat (r = .49, P < .01), but not with trans fatty acid intake (r = .11, not significant [NS]). Fasting glucose also correlated with total (r = .39, P < .05) and monounsaturated fat intakes (r = .37, P < .05). In multivariate analysis, both total and saturated fat intake were strong single predictors of fasting insulin (R2 approximately .25), and a model combining dietary and anthropometric measures accounted for 47% of the variance in fasting insulin. Significant relationships were observed between fasting insulin and the serum CE enrichments of myristic (C14:0), palmitoleic (C16:1), and dihomo-gamma-linolenic (C20:3n-6) acids. In multivariate analysis, a model containing CE 14:0 and percent body fat explained 45% of the variance in fasting insulin, and C14:0 and age explained 30% of the variance in fasting glucose. PL C20:3n-6 explained 30% of the variance in fasting insulin, and a model including PL C18:1n-11 cis, C20:3n-6, age and body fat had an R2 of .58. In conclusion, self-reported intake of saturated and monounsaturated fats, but not trans fatty acids, are associated with markers of insulin resistance. Furthermore, enhancement of dihomo-gamma-linolenic and myristic acids in serum CE and PL, presumably markers for dietary intake, predicted insulin resistance.

Adult↗

PubMed2001

Evaluation of body fat in fatter and leaner 10-y-old African American and white children: the Baton Rouge Children's Study.

BACKGROUND: Only a few published studies in children used several methods to compare body fat in large groups of fatter and leaner multiethnic children. We hypothesized that the preferred methods of determining body fat may differ in children with larger compared with smaller amounts of body fat, in boys compared with girls, and in African Americans compared with whites. OBJECTIVE: Our objective was to evaluate several methods of predicting body fat in 10-12-y-old white and African American boys and girls. DESIGN: The body fat of 129 African American and white boys and girls aged 10-12 y, distributed equally by sex and race, was measured with use of dual-energy X-ray absorptiometry (DXA), underwater weighing (densitometry), isotope dilution (H(2)18O), bioelectrical impedance, skinfold thicknesses, corporal diameters, and circumferences. RESULTS: With use of DXA as the criterion variable, body fat was bimodally distributed in the boys and skewed to higher values in the girls. Biceps skinfold thickness had the highest predictive value of any single skinfold thickness compared with DXA fat. All formulas for estimating body fat from skinfold thicknesses, body density, or impedance performed better in the children in the upper one-half of the fat distribution (the fatter children) than in those in the lower one-half (the leaner children). Body mass index was highly correlated with body fat (R2 = 0.77); there was a good correlation for the fatter children (R2 = 0.66) and no correlation for the leaner children (R2 = 0.09). The hydration of the fat-free mass was significantly higher in the fatter children than in the leaner ones (79.2% compared with 76.7%). CONCLUSIONS: These data are consistent with the hypothesis that all methods of estimating body fat work better in children with larger amounts of body fat. The best formulas use skinfold thicknesses, bioelectrical impedance, and a 4-compartment model.

Absorptiometry, Photon↗

PubMed2000

Changes in body composition with conjugated linoleic acid.

Conjugated linoleic acid has been shown to reduce body fat accumulation in several animal models. We have conducted several studies in AKR/J mice showing that CLA reduces body fat accumulation whether animals are fed a high-fat or low-fat diet, with no effect on food intake. One mechanism by which CLA reduces body fat is by increased energy expenditure, which is observed within one week of CLA feeding and is sustained for at least six weeks. The increased energy expenditure is sufficient to account for the decreased fat accumulation. Increased uncoupling protein gene expression does not appear to be involved in the increased energy expenditure. We have observed increased fat oxidation but no decrease in de novo fat biosynthesis with CLA feeding. We have also observed increased liver weights and plasma insulin levels with higher doses of CLA. In all of the studies we have conducted to date we have used a CLA preparation that contains several isomers, primarily c9,t11 and t10,c12. It was assumed that the active form was c9,t11, as CLA was identified as an anticarcinogenic compound from cooked beef, of which the c9,t11 form accounts for 60% to 80% of the CLA. Most of the studies conducted so far must be repeated using the purified isomers in order to determine which isomers are responsible for each of the identified actions of CLA.

Adipose Tissue↗

PubMed2000

The effect of an herbal dietary supplement containing ephedrine and caffeine on oxygen consumption in humans.

OBJECTIVE: To determine if an herbal dietary supplement for weight loss increases metabolism. DESIGN: Measurement of peak oxygen consumption in response to the supplement followed by a double-blind placebo-controlled crossover measurement of oxygen consumption in response to the supplement. SETTING: The study was conducted in an academic research clinic. SUBJECTS: Ten obese females (aged 41 +/- 4 years [body mass index (BMI)] 33.3 +/- 2.6 kg/m2) participated in the peak oxygen consumption test; six of these females participated in the crossover trial. INTERVENTIONS AND OUTCOME MEASURES: Peak oxygen consumption was measured for 45 minutes after taking two herbal dietary supplement capsules orally, each containing the equivalent of 10 mg of caffeine and 5 mg of ephedrine. The crossover trial measured oxygen consumption for 45 minutes after taking two herbal dietary supplement capsules or two placebo capsules orally. RESULTS: The herbal dietary supplement increased peak oxygen consumption 0.178 +/- 0.03 (SEM) kcal/min (8.01 +/- 1.35 kcal/min expressed over 45 minutes) above baseline (p < 0.0001), and 2.0 +/- 0.56 kcal/min over 45 minutes compared to placebo (p < 0.006). CONCLUSIONS: The herbal dietary supplement increased oxygen consumption when taken according to the package directions. The significance of this rise for weight loss requires further research.

Caffeine↗

PubMed2000

Differential oxidation of individual dietary fatty acids in humans.

BACKGROUND: Dietary fatty acids that are more prone to oxidation than to storage may be less likely to lead to obesity. OBJECTIVE: The aim of this study was to determine the effect of chain length, degree of unsaturation, and stereoisomeric effects of unsaturation on the oxidation of individual fatty acids in normal-weight men. DESIGN: Fatty acid oxidation was examined in men consuming a weight-maintenance diet containing 40% of energy as fat. After consuming the diet for 1 wk, subjects were fed fatty acids labeled with (13)C in the methyl or carboxyl position (10 mg/kg body wt). The fatty acids fed in random order were laurate, palmitate, stearate, oleate, elaidate (the trans isomer of oleate), linoleate, and linolenate blended in a hot liquid meal. Breath samples were collected for the next 9 h and the oxidation of each fatty acid was assessed by examining liberated (13)CO(2) in breath. RESULTS: Cumulative oxidation over the 9-h test ranged from a high of 41% of the dose for laurate to a low of 13% of the dose for stearate. Of the 18-carbon fatty acids, linolenate was the most highly oxidized and linoleate appeared to be somewhat conserved. (13)C recovery in breath from the methyl-labeled fatty acids was approximately 30% less than that from the carboxyl-labeled fatty acids. CONCLUSIONS: In summary, lauric acid is highly oxidized, whereas the polyunsaturated and monounsaturated fatty acids are fairly well oxidized. Oxidation of the long-chain, saturated fatty acids decreases with increasing carbon number.

Adult↗

PubMed2000

Conjugated linoleic acid persistently increases total energy expenditure in AKR/J mice without increasing uncoupling protein gene expression.

AKR/J mice fed a high fat diet were treated with a 1% (1 g/100 g) admixture of conjugated linoleic acids (CLA) for 5 wk and compared with control mice. Body weights, energy intakes and energy expenditure (EE) determined by indirect calorimetry were measured weekly. CLA treatment reduced adipose depot weights by approximately 50% but had no significant effects on either body weight or energy intake. CLA increased EE persistently by an average of 7.7% throughout the 5-wk experiment. This greater EE, despite no difference in energy intake, was sufficient to account for the lower body fat stores in the CLA-treated mice. De novo fatty acid biosynthesis in adipose tissue, measured by incorporation of deuterium-labeled water, was not decreased by CLA treatment and therefore did not explain the lower adipose lipid in these mice. Expression of uncoupling protein (UCP) in skeletal muscle, white adipose tissue and kidney was not affected by CLA treatment. In brown adipose tissue, UCP1 expression was not affected by CLA treatment. However, UCP2 expression, although quite low, was significantly greater in CLA-fed mice. We conclude that CLA acts to reduce body fat stores by chronically increasing metabolic rate. This effect on metabolic rate is likely not due to increased UCP gene expression. Furthermore, the reduced body fat is not due to decreased de novo fatty acid synthesis in white adipose tissue.

Adipose Tissue↗

PubMed1999

Long-term calorie restriction reduces energy expenditure in aging monkeys.

Calorie restriction to produce stable long-term adult body weight for approximately 10 years prevents obesity and diabetes in middle-aged rhesus monkeys. To determine whether this dietary regimen also alters energy metabolism, the doubly labeled water method was used to measure total daily energy expenditure. Six adult male rhesus monkeys, which had been calorie-restricted for more than 10 years, were compared to 8 control adult monkeys, which had been fed ad libitum for their entire lives. The calorie-restricted monkeys weighed less than the ad-libitum fed monkeys and had a lower lean body mass and lower fat mass. Total daily energy expenditure was lower in the calorie-restricted than in the ad-libitum fed monkeys, even when corrected for differences in body size using body weight (563 +/- 64 vs 780 +/- 53 kcal/d; p < .04), surface area (547 +/- 67 vs 793 +/- 56 kcal/d; p < .05), or lean body mass (535 +/- 66 vs 801 +/- 54 kcal/d; p < .02) as covariates. Thyroxine (T4) was reduced and the free thyroxine index was suggestively lower in the calorie-restricted monkeys whereas triiodothyronine (T3) was not significantly different. Activity in calorie-restricted monkeys was similar to that of a weight-matched younger adult comparison group. We conclude that the process of preventing obesity by long-term caloric restriction causes a significant and sustained long-term reduction in energy expenditure, even when corrected for lean body mass.

Adipose Tissue↗

PubMed1999

Eradication of Helicobacter pylori infection with proton pump-based triple therapy in patients in whom bismuth-based triple therapy failed.

To study the effects of treatment of Helicobacter pylori infection in a hyperendemic population, 143 infected patients from the region of Nariño, Colombia, were treated for 2 weeks with clarithromycin (500 mg twice a day), amoxicillin (1 g twice a day), and either lansoprazole (30 mg twice a day) or omeprazole (30 mg twice a day). All patients belong to a low socioeconomic strata, had multifocal atrophic gastritis documented by gastric biopsies, and had been treated previously and unsuccessfully for 2 weeks with bismuth subsalicylate (262 mg four times a day), amoxicillin (500 mg three times a day), and metronidazole (400 mg three times a day). 13C-urea breath tests were performed 6, 12, 24, and 60 weeks after completing therapy. The 13C-urea breath test was negative in 79.7% of patients 1 month after finishing therapy, and in 69.2% of patients 1 year after finishing treatment. There were no differences in eradication rates between patients treated with omeprazole versus lansoprazole. Dyspepsia symptoms decreased from 74% in patients at baseline to 19% at the time of finishing treatment. In low-socioeconomic status populations with hyperendemic infection, triple therapy using omeprazole or lansoprazole plus clarithromycin and amoxicillin is an effective alternative when previous standard bismuth-based triple therapy has failed.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed1999

Conjugated linoleic acid rapidly reduces body fat content in mice without affecting energy intake.

Recent reports have demonstrated that conjugated linoleic acid (CLA) has effects on body fat accumulation. In our previous work, CLA reduced body fat accumulation in mice fed either a high-fat or low-fat diet. Although CLA feeding reduced energy intake, the results suggested that some of the metabolic effects were not a consequence of the reduced food intake. We therefore undertook a study to determine a dose of CLA that would have effects on body composition without affecting energy intake. Five doses of CLA (0.0, 0.25, 0.50, 0.75, and 1.0% by weight) were studied in AKR/J male mice (n = 12/group; age, 39 days) maintained on a high-fat diet (%fat 45 kcal). Energy intake was not suppressed by any CLA dose. Body fat was significantly lower in the 0.50, 0.75, and 1.0% CLA groups compared with controls. The retroperitoneal depot was most sensitive to the effects of CLA, whereas the epididymal depot was relatively resistant. Higher doses of CLA also significantly increased carcass protein content. A time-course study of the effects of 1% CLA on body composition showed reductions in fat pad weights within 2 wk and continued throughout 12 wk of CLA feeding. In conclusion, CLA feeding produces a rapid, marked decrease in fat accumulation, and an increase in protein accumulation, at relatively low doses without any major effects on food intake.

Adipose Tissue↗

PubMed1998

Assessment of energy intake underreporting by doubly labeled water and observations on reported nutrient intakes in children.

OBJECTIVE: To compare reported energy intake with energy expenditure using doubly labeled water (DLW). Additionally, we compared reported nutrient intakes of our subject population with national survey population data from the third National Health and Nutrition Examination Survey (NHANES III). DESIGN: This was a cross-sectional study of children, balanced by race and gender, primarily characterized by 4 body types: lean, obese, centrally fat, or peripherally fat. SUBJECTS/SETTING: Children (n=118; mean age=10 years) kept 8-day food records, with nutritionists recording weekday school lunch intakes. These subjects, assisted by their parents, recorded all breakfasts, dinners, snacks, and weekend lunches. STATISTICAL ANALYSES PERFORMED: Data were analyzed using least squares analysis of variance with the general linear models procedure. Tukey's test was used for multiple comparisons of predicted treatment means. RESULTS: Mean daily energy intake was underreported by 17% to 33% of energy expenditure. The tendency to underreport increased with age. Underreporting occurred in all groups and subgroups studied. Reported mean intakes of vitamin A, vitamin E, vitamin B-6, calcium, zinc, and copper were less than 70% of the Recommended Dietary Allowance (RDA) for African-American girls, whereas African-American boys reported similarly low intakes of copper. On average, white girls reported intakes less than 70% of the RDA for zinc and copper, whereas white boys reported low intakes of copper (60% of the RDA). Reported intakes in general were somewhat lower than those reported in NHANES III. APPLICATIONS/CONCLUSIONS: Dietetics professionals may modify the nutritional advice they give to patients/subjects based on food intake records and other data. For children, particularly, it is imperative that ethnic and gender differences be taken into consideration and that all foods eaten be accounted for as much as possible.

Black or African American↗

PubMed1998

Role of energy expenditure in the development of pediatric obesity.

The role that energy expenditure plays in pediatric obesity was somewhat confused by early research purporting to show that, as a group, obese children have lower energy intakes than do lean children. On the basis of this intake data, the conclusion was drawn that obese persons are somehow energy efficient, leading to weight gain. More recent research examining energy expenditure has shown clearly that, as a group, obese children have higher energy expenditures than do their lean counterparts. With the advent of the doubly labeled water method for determining free-living energy expenditure, it has been shown that obese children underreport intake significantly more than do lean children. When measurements are properly adjusted for differences in body size, there are generally no major differences in energy expenditure between lean and obese groups. However, in some cross-sectional studies, a low level of physical activity has been shown to be related to current body fatness. In addition, longitudinal studies have shown that a low level of energy expenditure, particularly energy expended in physical activity, is associated with both body fatness and weight gain.

Body Water↗

PubMed1997

Relationship between resting metabolic rate and the composition of the fat-free mass.

Although a low resting metabolic rate (RMR) has been shown to be a risk factor for future weight gain, little is known about the mechanisms determining its level. We tested the hypothesis that the composition of the fat-free mass (FFM) is a main determinant of RMR. If this hypothesis is true, a regression model including internal organ masses as independent variables should explain a larger fraction of the variance in RMR than is explained using only FFM as a predictor. We measured fat mass by hydrodensitometry, liver and kidney volumes by computed tomography (CT), heart mass by echocardiography, muscle mass by dual-energy x-ray absorptiometry (DEXA), and RMR by calorimetry in 40 subjects. FFM and fat mass explained 83% of the variability in RMR (standard error of the estimate [SEE], 420 kJ/d) in a multiple regression analysis. Combinations of organ and muscle masses performed as well as but not better than stepwise multiple regression models. The fact that the composition of the lean mass could not improve the prediction of RMR in comparison to the traditional FFM-fat mass model suggests that the weight of internal organs is not a main determinant of RMR. This may indicate that the variability in RMR is associated with variation in energy expenditure per kilogram of tissue of the individual organs.

Adipose Tissue↗

PubMed1997

Nutritional factors and Helicobacter pylori infection in Colombian children.

BACKGROUND: Helicobacter pylori infection occurs most frequently in impoverished populations; however, little is known about specific determinants of susceptibility. This report describes the relationship between H. pylori infection and nutritional indicators among children from a rural village in the Colombian Andes, where a prevalence of 69% was observed in children from 2 to 9 years old. METHODS: In a cross-sectional study of 684 children, comprising 92% of the 2- to 9-year-old population of Aldana, Colombia, information was obtained on dietary factors by questionnaire, height and weight by direct measurement, and H. pylori status using the carbon-13 urea breath test. Multivariate logistic regression was used to estimate relative risks for nutritional indicators. RESULTS: The infection was least frequent among children who are several servings of fruits and vegetables daily, drank two or more cups of milk daily, and were in the upper quintile of height for their age. The odds of infection increased 19-fold (95% confidence interval, 4.0-91.9) among children who consumed less than two daily servings of fruits and vegetables compared with the modal intake of three to five daily servings. Children whose daily vitamin C intake from fruits and vegetables was less than 40 mg had greatly increased odds of infection (odds ratio, 7.2; 95% confidence interval, 1.5-34.1) compared to the modal intake of 80-119 mg; for beta-carotene, the odds ratio was 3.1 (95% confidence interval, 1.2-7.9) for intakes of less than 300 IU per day, compared with the modal daily intake of 900 IU or more. CONCLUSIONS: The results of this population-based study suggest that nutritional factors may play a role in determining susceptibility to H. pylori infection.

Aging↗

PubMed1997

A paradigm of experimentally induced mild hyperthyroidism: effects on nitrogen balance, body composition, and energy expenditure in healthy young men.

Although T3 exerts major regulatory actions in both animals and humans, most clinical studies of T3 administration have been relatively short term. The present study examined the effects of more than 2 months (63 days) of low dose T3 treatment on nitrogen balance, body composition, 24-h energy expenditure (EE), and protein turnover in seven healthy men studied at an in-patient metabolic unit. Subjects were also randomly assigned to either high or low fat diets to determine the effects of diet composition. T3 treatment produced significant losses in both lean mass (1.5 +/- 0.3 kg) and fat mass (2.7 +/- 0.4 kg) by 6 weeks, with similar reductions in both at 9 weeks. The high fat diet somewhat attenuated the loss of body fat. Nitrogen balance was significantly negative for the first 3 weeks of T3 treatment, but tended to return to baseline thereafter. There were no significant effects of treatment on protein turnover at 9 weeks, although there was a slight increase in leucine oxidation (P = 0.07). Despite the apparent adaptation in nitrogen balance, total 24-h EE and sleeping EE were significantly increased at 9 weeks. We conclude that although healthy men are able to adapt to mild hyperthyroidism in terms of nitrogen balance, they exhibit significant and persistent changes in fat and fat-free mass as well as energy balance.

Adult↗

PubMed1996

Helicobacter pylori infection in the Colombian Andes: a population-based study of transmission pathways.

In 1992, the authors studied Helicobacter pylori infection and exposures relevant to person-to-person, waterborne, foodborne, and zoonotic transmission in a census sample of 684 2-9-year-old children in Aldana, Nariño, a rural community in the Colombian Andes. H. pylori prevalence, as determined by the 13C-urea breath test, was 69%, and prevalence increased from 53% in 2 year-olds to 87% in 9 year-olds. Beginning at 3 years of age, a higher percentage of males compared with females were infected. Odds ratios were estimated by multivariate logistic regression to control for mutual confounding by transmission-pathway proxy variables and socioeconomic indicators. Among transmission-pathway proxies, the strongest predictor of H. pylori status was the number of persons who lived in the home, with the number of children apparently being of greater importance than the number of adults. Swimming in rivers, streams, or pools increased the odds of infection, as did using streams as a drinking water source. Children who frequently consumed raw vegetables were more likely to have the infection, and children who had contact with sheep also had increased prevalence odds. Because the results did not implicate a single mode of transmission, the possibility of multiple pathways is indicated.

Age Distribution↗

PubMed1996

Energy expenditure.

Although human energy expenditure has been studied for over 100 years, many unanswered questions remain regarding the role that individual components of energy expenditure have in the etiology of obesity. Most techniques for measuring physical activity, the most variable component of TDEE, are less than adequate, and differences in energy metabolism are difficult to detect in a static comparison. When energy expenditure is examined in obese and lean subjects at one point in time, there frequently are no differences in energy expenditure when appropriately normalized. However, when subjects are studied longitudinally or when the system is perturbed (such as overfeeding or exercising), differences can be observed. Using a combination of the techniques available today, each component can be reliably studied, and the role that each has in the development of obesity can be ascertained.

Energy Metabolism↗