PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Energy Intake”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,369 records · Page 76Linked to original sources
PubMed1998

[Energy expenditure at rest and obesity].

Adult human body has to have, because of every day fluctuating energy intake and energy needs, very precious adaptive mechanisms for maintenance of heat homeostasis in the body and nearly stable body weight and body composition, which are optimal for life and reproduction. These short term functioning adaptive mechanisms are called "empty biochemical mechanisms", where chemically bound energy is transformed to heat without work performance. These mechanisms are present on the cellular level (substrates cycles, uncoupling of respiration chain), on the interorgan metabolic level (glycolysis and gluconeogenesis between liver and adipose tissue-glucose-lactate cycle). Central nervous system controls them via many factors; the most important are catecholamines, leptin, insulin, thyroid hormones, cortisol, growth and sex hormones. Neurotransmitters and neuronal net influence energy intake and other behavior. Obesity seems to be associated with the amelioration or overcoming of possibilities of function short-term effective adaptive mechanisms.

Adaptation, Physiological↗
PubMed2000

Interactions between physical activity and diet in the regulation of body weight.

The increasing worldwide prevalence of obesity suggests that there is a chronic positive energy balance. This situation implies poor coupling between energy intake and energy expenditure, but the contribution of each of these factors remains unclear. Epidemiological data suggests that physical activity has a role in the prevention of weight gain, although there is little evidence that it has a beneficial role in weight loss. High-fat diets have also been implicated, evidence from a variety of sources suggests that diets high in fat undermine appetite regulatory mechanisms. There has been much research to investigate the coupling between energy expenditure and energy intake in the short term in an attempt to elucidate some of the mechanisms involved. However, mechanisms regulating appetite are very complex, and it is currently unclear at which points physical activity and diet may have an influence.

Appetite Regulation↗
PubMed1997

The new biology of body weight regulation.

A growing body of evidence suggests that energy balance (the difference between energy intake and expenditure) and body fuel stores in the form of adipose tissue are maintained by the body within a narrow range. This regulation of adiposity is mediated by the secretion of hormonal signals into the circulation in proportion to body adipose stores and their subsequent actions on brain systems that control caloric intake and energy expenditure. As a result, changes in energy balance sufficient to alter fuel stores elicit compensatory changes in energy intake and expenditure that return fat stores to their regulated level. Recent scientific break-through have identified the key components of this physiologic system. These include the circulating signals, leptin (the hormone encoded by the ob gene that is secreted by fat cells) and the pancreatic hormone insulin; and brain peptides such as neuropeptide Y, which is released from nerve terminals in the hypothalamus to elicit changes in feeding behavior and energy expenditure that mediate adaptive changes in energy balance. This article reviews the discovery of leptin and its receptor and discusses the interaction of leptin and insulin with the hypothalamic neuropeptide Y system. These observations provide a basis for understanding how weight lost during a period of negative energy balance (because of the inability to consume and/or store sufficient energy to meet ongoing energy demands) is eventually recovered. As our understanding of this weight-regulatory system increases, new insights into the causes of human obesity are likely to follow. Such insights may yield improvements in the medical and nutrition management of obese patients.

Animals↗
PubMed1999

Quantitative genetics of energy balance--lessons from animal models.

Evidence for quantitative genetic variation in components of energy balance in animals is overwhelming. Much of this evidence is drawn from livestock species and relevant rodent models, especially long-term selection lines. This mini-review summarizes findings from several animal studies that have characterized quantitative genetic variation in energy intake and energy expenditure. Applications of this information toward understanding and treatment of human obesity are explored.

Animals↗
PubMed2004

Mind versus metabolism in the control of food intake and energy balance.

In a restrictive food environment, the homeostatic control system regulates body weight and adiposity with remarkable precision. However, this regulation appears to break down in many genetically predisposed individuals under conditions prevailing in the modern era characterized by a sedentary lifestyle and easy availability of large portions of palatable and calorically dense food. The nervous system is the main interface by which food-related environmental factors influence the regulatory process. Thus, focusing on the neural systems located in the telencephalon dealing with environmental factors, and on their connections with the homeostatic regulatory system distributed mainly in the hypothalamus and brainstem, should result in new drug targets and behavioral strategies for prevention and therapy. The structures providing this interface with the environment are involved in the initiation, procurement, and appetitive phases of ingestive behavior and associative learning before, during, and after the consummatory phase. It is thought that learned and unlearned representations of foods and food cues in the orbitofrontal and other cortical areas are filtered for affective/emotional value in the amygdala and for motivational salience in the nucleus accumbens/ventral striatum to initiate goal-directed motor programs. Internal state signals generated by the metabolic sensing mechanisms in the hypothalamus interact with each of these corticolimbic structures through reciprocal connections. While many projections from the hypothalamus contain the various "feeding peptides," the neurochemistry of projections to the hypothalamus has not been well characterized.

Animals↗
PubMed2003

Biopsychosocial characteristics of overweight and obese primary care patients: do psychosocial and behavior factors mediate sociodemographic effects?

BACKGROUND: The increasing prevalence of obesity and obesity-related conditions in primary care settings challenges the health care system. Thus, we used available baseline data from an on-going clinical trial to examine the biopsychosocial characteristics of overweight and obese primary care patients. The primary research objective was to ascertain whether theoretically important psychosocial and behavioral variables mediate the empirical relationships between sociodemographic factors and body mass index (BMI). METHODS: Overweight or obese primary care patients (n=665) enrolled in an on-going trial of a cognitive-behavioral obesity intervention provided baseline sociodemographic, psychosocial, nutritional, physical activity, and anthropometric data that were analyzed via multiple regression. RESULTS: Lower educational attainment was associated with a higher BMI after controlling for decisional balance, social support, self-efficacy, energy intake, and energy expenditure (P<0.05). In contrast, ethnicity was not associated with BMI after controlling for the psychosocial and behavioral variables. Decisional balance and social support variables were associated with BMI and energy intake, but the directions of some of the associations were not consistent with a priori expectations. CONCLUSIONS: Overall, we found some evidence of mediation by the psychosocial and behavioral variables of the relationship between ethnicity and BMI, but not for the relationship between education and BMI. In addition, some of the relationships between the psychosocial variables and BMI were opposite of our expectations.

Aged↗
PubMed1997

Energy balance and liver respiratory activity in rats fed on an energy-dense diet.

In the present study energy balance and liver respiratory activity were studied in rats fed on either a control diet or an energy-dense diet. Liver respiration was assessed both without added substrates and after the addition of hexanoate, glycerol, or sorbitol. The effect of ouabain on hexanoate-supported respiration was also determined. Metabolizable energy intake and energy expenditure increased in rats fed on an energy dense diet, but body-weight gain, as well as lipid and protein content, remained unchanged. When net energy expenditure, obtained excluding the total cost of storage, was expressed as a percentage of metabolizable energy, significant differences were found between the two groups of rats. This finding supports the presence of regulatory mechanisms in rats fed on an energy-dense diet, which are useful to counteract development of obesity. In addition, a significant increase in liver respiratory activity was found in rats fed on an energy-dense diet, both in the basal state and in that stimulated by added substrates. Na/K-pump-dependent O2 consumption also increased in rats fed on an energy-dense diet. The results indicate that a greater production of metabolic heat by the liver can contribute to the increased energy expenditure found in rats fed on an energy-dense diet.

Animal Feed↗
PubMed2002

Energy metabolism in humans at a lowered ambient temperature.

OBJECTIVE: Assessment of the effect of a lowered ambient temperature, ie 16 degrees C (61 degrees F), compared to 22 degrees C (72 degrees F), on energy intake (EI), energy expenditure (EE) and respiratory quotient (RQ) in men. DESIGN: Randomized within-subject design in which subjects stayed in a respiration chamber three times for 60 h each, once at 22 degrees C, and twice at 16 degrees C, wearing standardized clothing, executing a standardized daily activities protocol, and were fed in energy balance (EBI): no significant difference between EE and EI over 24 h). During the last 24 h at 22 degrees C, and once during the last 24 h at 16 degrees C, they were fed ad libitum. SUBJECTS: Nine dietary unrestrained male subjects (ages 24+/-5 y, body mass index (BMI) 22.7+/-2.1 kg/m(2), body weight 76.2+/-9.4 kg, height 1.83+/-0.06 m, 18+/-5% body fat). RESULTS: At 16 degrees C (EB), EE (total 24 h EE) was increased to 12.9+/-2.0 MJ/day as compared to 12.2+/-2.2 MJ/day at 22 degrees C (P<0.01). The increase was due to increases in sleeping metabolic rate (SMR; the lowest EE during three consecutive hours with hardly any movements as indicated by radar): 7.6+/-0.7 vs 7.2+/-0.7 MJ/day (P<0.05) and diet-induced thermogenesis (DIT; EE-SMR, when activity induced energy expenditure as indicated by radar=0): 1.7+/-0.4 vs 1.0+/-0.4 MJ/day (P<0.01). Physical activity level (PAL; EE/SMR) was 1.63-1.68. At 16 degrees C compared to at 22 degrees C, rectal, proximal and distal skin temperatures had decreased (P<0.01). RQ was not different between the two ambient temperature situations. During ad libitum feeding, subjects overate by 32+/-12% (at 22 degrees C) and by 34+/-14% (at 16 degrees C). Under these circumstances, the decrease of rectal temperature at 16 degrees C was attenuated, and inversely related to percentage overeating (r(2)=0.7; P<0.01). CONCLUSION: We conclude that at 16 degrees C, compared to 22 degrees C, energy metabolism was increased, due to increases in SMR and DIT. Overeating under ad libitum circumstances at 16 degrees C attenuated the decrease in rectal core body temperature.

Activities of Daily Living↗
PubMed1999

Fat balance and hepatic mitochondrial function in response to fat feeding in mature rats.

OBJECTIVE: To study the effects of fat feeding on fat balance and hepatic mitochondrial function in postpubertal male rats. DESIGN: Rats were fed low fat, medium fat or high fat diet for 15 days. MEASUREMENTS: Energy balance, body composition, resting metabolic rate (RMR), mitochondrial state 3 and state 4 oxygen consumption rates, succinic dehydrogenase (EC 1.3.99.1) and mitochondrial alpha-glycerophosphate dehydrogenase (EC 1.1.1.8) activities. RESULTS: Rats fed medium fat or high fat diet, in comparison with rats fed low fat diet, showed a significantly greater metabolisable energy intake and energy expenditure. In addition, body energy and lipid gains were significantly higher in rats fed medium fat or high fat diet than in rats fed low fat diet. Mitochondrial respiration and enzymatic activities were not affected by fat feeding. CONCLUSION: These results indicate that in postpubertal rats fed high fat diets, the increase in energy expenditure counteracts only in part the excess fat deposition. This is probably due to the impairment in regulatory responses, and enhances thermogenesis.

Adipose Tissue↗
PubMed2005

Interindividual variation in posture allocation: possible role in human obesity.

Obesity occurs when energy intake exceeds energy expenditure. Humans expend energy through purposeful exercise and through changes in posture and movement that are associated with the routines of daily life [called nonexercise activity thermogenesis (NEAT)]. To examine NEAT's role in obesity, we recruited 10 lean and 10 mildly obese sedentary volunteers and measured their body postures and movements every half-second for 10 days. Obese individuals were seated, on average, 2 hours longer per day than lean individuals. Posture allocation did not change when the obese individuals lost weight or when lean individuals gained weight, suggesting that it is biologically determined. If obese individuals adopted the NEAT-enhanced behaviors of their lean counterparts, they might expend an additional 350 calories (kcal) per day.

Activities of Daily Living↗
PubMed1998

Slow restoration of LH pulsatility by refeeding in energetically disrupted women.

In other energy-restricted mammals, a single large meal restores luteinizing hormone (LH) pulsatility within a few hours. To determine whether this is so in women, we measured LH pulsatility during the 5th day of low energy availability [dietary energy intake - exercise energy expenditure = 10 kcal . kg lean body mass (LBM)-1 . day-1] and during a 6th day of aggressive refeeding (90 kcal . kg LBM-1 . day-1) in 15 meals providing 4,100 kcal for an energy availability of 75 kcal . kg LBM-1 . day-1. Low energy availability raised beta-hydroxybutyrate 1,000% (P < 0.001) and reduced plasma glucose 15% (P < 0.01), insulin 63% (P < 0.001), and triiodothyronine 22% (P < 0.005). In five of eight subjects, low energy availability also unambiguously suppressed LH pulse frequency 57% to 8.2 +/- 1.5 pulses/24 h (P < 10(-4)) and raised LH pulse amplitude 94% to 3.1 +/- 0.3 IU/l (P < 10(-4)), levels below the 5th and above the 95th percentile, respectively, in energy-balanced women. Aggressive refeeding restored beta-hydroxybutyrate, glucose, and insulin, but not triiodothyronine. In the five women with unambiguously disrupted LH pulsatility, aggressive refeeding had no effect on LH pulse amplitude (P > 0.9) and raised LH pulse frequency only slightly (2.4 +/- 0.6 pulses/24 h, P = 0.04) and not above the fifth percentile. This striking contrast between women and other mammals may be another clue to the unidentified mechanism mediating the effect of energy availability on LH pulsatility.

3-Hydroxybutyric Acid↗
PubMed2001

Limits to sustainable human metabolic rate.

There is a limit to the performance of an organism set by energy intake and energy mobilization. Here, the focus is on humans with unlimited access to food and for whom physical activity can be limited by energy mobilization. The physical activity level (PAL) in the general population, calculated as doubly-labelled-water-assessed average daily metabolic rate as a multiple of basal metabolic rate, has an upper limit of 2.2-2.5. The upper limit of sustainable metabolic rate is approximately twice as high in endurance athletes, mainly because of long-term exercise training with simultaneous consumption of carbohydrate-rich food during exercise. Endurance athletes have an increased fat-free mass and can maintain energy balance at a PAL value of 4.0-5.0. High altitude limits exercise performance as a result of combined effects on nutrient supply and the capacity to process nutrients. Thus, trained subjects climbing Mount Everest reached PAL values of 2.0-2.7, well below the observed upper limit at sea level.

Altitude↗
PubMed1992

Socioeconomic and behavioral correlates of body mass index in black adults: the Pitt County Study.

BACKGROUND: Obesity is more prevalent among Black women than Black men, but there is little information on the correlates of obesity in Blacks. This study describes the relations of sociodemographic factors and health behaviors to body mass index in a southern, Black population. METHODS: In 1988, a community probability sample of 1784 Black adults, aged 25 to 50, was examined in Pitt County, NC. RESULTS: More women than men were at least 20% overweight (57% vs 36%). The relation of socioeconomic status (a composite of education and occupation) to age-adjusted body mass index level was inverse in women but not in men. Body mass index did not differ with either current energy intake or energy expenditure. Smokers and drinkers had lower age-adjusted levels than non-smokers and abstainers. CONCLUSIONS: Since the excess body mass index levels associated with low socioeconomic status in women could not be explained after controlling for adverse health behaviors, further epidemiologic study of risk factors for obesity in Black women is recommended.

Adult↗
PubMed2001

Plasma leptin and exercise: recent findings.

The cloning of murine and human obese genes in 1994, and the subsequent identification that the product of the obese gene, leptin, is secreted from adipose tissue, stimulated a tremendous amount of interdisciplinary interest in adipose tissue endocrinology and the potential role of this tissue in the regulation of energy balance. Exercise, with concomitant changes in fuel flux, systemic hormone levels and energy expenditure, may contribute to the regulation of plasma leptin levels and presumably, leptin action. The initial work characterising the leptin-exercise relationship was equivocal. Cross-sectional studies provided some mixed evidence regarding the relationship between aerobic capacity or habitual physical activity and plasma leptin. In contrast, studies on acute bouts of exercise and exercise training interventions have, with few exceptions, suggested that exercise does not alter systemic leptin independent of changes in fat mass. In general, these studies did not carefully control for energy balance, and sampled only a single fasting plasma leptin level. Two recent studies utilising experimental designs in which energy balance was controlled and 24-hour profiles of plasma leptin were determined have provided the most compelling evidence to date of the interaction between exercise, energy balance and systemic leptin in humans. These studies provide a clear explanation for the apparent lack of an acute effect of exercise on systemic leptin and underscore the importance of clearly defining the balance between energy intake and energy expenditure when studying the physiology of leptin. The aim of this brief review is to provide an overview of the interaction between energy expenditure during physical activity and systemic leptin level. Special emphasis will be placed on those studies in which energy intake/balance was carefully controlled.

Circadian Rhythm↗
PubMedDate not supplied

[Body mass index and its relationship to nutritional and socioeconomic variables: a linear regression approach to a Brazilian adult sub-population].

This paper focuses on the relationship between body mass index (BMI) and family energy intake, occupational energy expenditure, per capita family expenditure, sex, age, and left arm circumference for a group of Brazilian adults randomly selected among those interviewed for a survey on food consumption and family budgets, called the National Family Expenditure Survey. The authors discuss linear regression methodological issues related to treatment of outliers and influential cases, multicollinearity, model specification, heteroscedasticity, as well as the use of two-level variables derived from samples with complex design. The results indicate that the model is not affected by outliers and that there are no significant specification errors. They also show a significant linear relationship between BMI and the variables listed above. Although the hypothesis tests indicate significant heteroscedasticity, its corrections did not significantly change the model's parameters, probably due to the sample size (14,000 adults), making hypothesis tests more rigorous than desired.

Adult↗