Metabolic predictors of obesity. Contribution of resting energy expenditure, thermic effect of food, and fuel utilization to four-year weight gain of post-obese and never-obese women.

Obligatory thermogenesis is a necessary accompaniment of all metabolic processes involved in maintenance of the body in the living state, and occurs in ail organs. It includes energy expenditure involved in ingesting, digesting, and processing food (thermic effect of food (TEF)). At certain life stages extra energy expenditure for growth, pregnancy, or lactation would also be obligatory. Facultative thermogenesis is superimposed on obligatory thermogenesis and can be rapidly switched on and rapidly suppressed by the nervous system. Facultative thermogenesis is important in both thermal balance, in which control of thermoregulatory thermogenesis (shivering in muscle, nonshivering in brown adipose tissue (BAT)) balances neural control of heat loss mechanisms, and in energy balance, in which control of facultative thermogenesis (exercise-induced in muscle, diet-induced thermogenesis (DIT) in BAT) balances control of energy intake. Thermal balance (i.e., body temperature) is much more stringently controlled than energy balance (i.e., body energy stores). Reduced energy expenditure for thermogenesis is important in two types of obesity in laboratory animals. In the first type, deficient DIT in BAT is a prominent feature of altered energy balance. It may or may not be associated with hyperphagia. In a second type, reduced cold-induced thermogenesis in BAT as well as in other organs is a prominent feature of altered thermal balance. This in turn results in altered energy balance and obesity, exacerbated in some examples by hyperphagia. In some of the hyperphagic obese animals it is likely that the exaggerated obligatory thermic effect of food so alters thermal balance that BAT thermogenesis is suppressed. In all obese animals, deficient hypothalamic control of facultative thermogenesis and (or) food intake is implicated.Key words: thermogenesis, brown adipose tissue, energy balance, obesity, cold, thermoregulation, diet.

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Evaluation of Variability in Resting Energy Expenditure and Its Relationship with Macronutrients and Gestational Weight Gain During the Second Trimester of Pregnancy (P11-136-19)

Current Developments in Nutrition ◽

10.1093/cdn/nzz048.p11-136-19 ◽

2019 ◽

Vol 3 (Supplement_1) ◽

Author(s):

Kiley Vander Wyst ◽

Matthew Buman ◽

Gabriel Shaibi ◽

Megan Petrov ◽

Elizabeth Reifsnider ◽

...

Keyword(s):

Weight Gain ◽

Energy Expenditure ◽

Total Energy ◽

Gestational Weight Gain ◽

Early Period ◽

Resting Energy Expenditure ◽

Dietary Composition ◽

Second Trimester ◽

Gestational Weight ◽

Resting Energy

Abstract Objectives Resting energy expenditure (REE) comprises 60% of total energy expenditure and variations may be associated with gestational weight gain (GWG). There is a paucity of research investigating the relationship between REE and GWG. We investigated variations in REE and dietary composition throughout the second trimester and their association with GWG. Methods In this controlled trial, pregnant women (N = 16, mean age of 29.9 ± 4.3 years) with a gestational age < 17 weeks used the Breezing™ device for 13 weeks. This device is a real-time metabolism tracker that measures REE via indirect calorimetry. Height, weight, REE, and dietary intake via 24-hr recall were assessed every 2 weeks. Rate of GWG was calculated as weight gain divided by number of study weeks. Early (EC, GA wks 14–21), late (LC, GA wks 21–28), and overall (OC, GA wks 14–28) changes in macronutrient composition, REE, and GWG were used to evaluate time-specific associations. Group differences were analyzed using a General Linear Model in SPSS Version 25. Results Among the 16 participants, 25% of women were normal weight, 50% were overweight, and 25% were obese at study start. Women had a total and rate of GWG of 8.1 ± 2.9 kg and 0.6 ± 0.2 kg/wk, respectively. REE increased 72 ± 211 kcals/d during the early period, 121 ± 294 kcals/d during the late period, and 200 ± 316 kcals/d overall (from 1544 ± 237 kcal/d to 1744 ± 384 kcal/d). Early changes in REE were significantly correlated with the late changes in total (r = 0.52, P = 0.04) and rate of weight gain (r = 0.54, P = 0.03). A correlation between overall changes in REE and total weight gain was moderate and approached significance, r = 0.44, P = 0.09. Changes in total energy, fat, carbohydrate, and protein intake were not correlated with changes in REE; however, a moderate relationship between early changes in REE and overall changes in energy intake approached significance, r = 0.46, P = 0.07. Changes in GWG and REE did not differ among normal, overweight, or obese women (EC: F(2,15) = 0.36, P = 0.70; LC: F(2,15) = 2.37, P = 0.13; OC: F(2.15) = 1.27, P = 0.31). Conclusions Early changes in REE demonstrated a moderate, positive correlation with total and rate of GWG suggesting that assessment of REE early in pregnancy may help understand changes in GWG. Future research that evaluates both REE and dietary composition throughout pregnancy may provide insight into appropriate GWG. Funding Sources Project HoneyBee, Arizona State University.

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Obese Women With Hypothyroidism Treated with Levothyroxine Have Reduced Resting Energy Expenditure

Clinical Thyroidology ◽

10.1089/ct.2020;32.218-220 ◽

2020 ◽

Vol 32 (5) ◽

pp. 218-220

Author(s):

Mary H. Samuels

Keyword(s):

Energy Expenditure ◽

Resting Energy Expenditure ◽

Obese Women ◽

Resting Energy

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Resting Energy Expenditure in Obese Women with Primary Hypothyroidism and Appropriate Levothyroxine Replacement Therapy

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/clinem/dgaa097 ◽

2020 ◽

Vol 105 (4) ◽

pp. e1741-e1748 ◽

Cited By ~ 3

Author(s):

Emanuele Muraca ◽

Stefano Ciardullo ◽

Alice Oltolini ◽

Francesca Zerbini ◽

Eleonora Bianconi ◽

...

Keyword(s):

Body Composition ◽

Energy Expenditure ◽

Replacement Therapy ◽

Resting Energy Expenditure ◽

Primary Hypothyroidism ◽

Normal Serum ◽

Fat Free Mass ◽

Model Assessment ◽

Obese Women ◽

Resting Energy

Abstract Context Growing evidence suggests that appropriate levothyroxine (LT4) replacement therapy may not correct the full set of metabolic defects afflicting individuals with hypothyroidism. Objective To assess whether obese subjects with primary hypothyroidism are characterized by alterations of the resting energy expenditure (REE). Design Retrospective analysis of a set of data about obese women attending the outpatients service of a single obesity center from January 2013 to July 2019. Patients A total of 649 nondiabetic women with body mass index (BMI) > 30 kg/m2 and thyrotropin (TSH) level 0.4–4.0 mU/L were segregated into 2 groups: patients with primary hypothyroidism taking LT4 therapy (n = 85) and patients with normal thyroid function (n = 564). Main outcomes REE and body composition assessed using indirect calorimetry and bioimpedance. Results REE was reduced in women with hypothyroidism in LT4 therapy when compared with controls (28.59 ± 3.26 vs 29.91 ± 3.59 kcal/kg fat-free mass (FFM)/day), including when adjusted for age, BMI, body composition, and level of physical activity (P = 0.008). This metabolic difference was attenuated only when adjustment for homeostatic model assessment of insulin resistance (HOMA-IR) was performed. Conclusions This study demonstrated that obese hypothyroid women in LT4 therapy, with normal serum TSH level compared with euthyroid controls, are characterized by reduced REE, in line with the hypothesis that standard LT4 replacement therapy may not fully correct metabolic alterations related to hypothyroidism. We are not able to exclude that this feature may be influenced by the modulation of insulin sensitivity at the liver site, induced by LT4 oral administration.

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