Daily energy expenditure across the course of lactation among urban Bangladeshi women

Measures of energy intake of lactating women in developing countries show that intakes are often lower than those recommended by international bodies, while fat-mass losses are often substantially less than the 3-4 kg used in the calculations of recommendations, suggesting that physiological adaptation must be commonplace among such women. The cost of lactation may be met by reduction in energy expenditure, including reduced physical activity, as well as by mobilization of bodily soft tissue. However, daily energy expenditure of lactating women has been shown to increase across the course of lactation among women in a rural population in the Philippines and an urban population in India, with a decline in body weight across the course of lactation in both studies. In the present study, total daily energy expenditure and anthropometric body composition were measured longitudinally in 68 mothers from a poor urban area of Dhaka, Bangladesh, at 0, 1, 2, 4, and 8 months of lactation, to determine whether the increasing energy expenditure across lactation observed elsewhere also occurs in Bangladeshi women. In addition, the extent to which an extended period of lactation was accompanied by weight and body fat change in these women was determined. Energy expenditure by heart-rate monitoring and activity report, and body composition from anthropometry was carried out four times across the 8-month period of lactation. A small decline in body fat mass and a significant increase in total energy expenditure across this period were observed, confirming similar observations elsewhere in the developing world.     

Effect of trunk load on the energy expenditure of treadmill walking and ergometer cycling

Data concerning the effect of trunk loads on the energy expenditure of various activities are scanty and partly conflicting. The energy expenditure of walking (4.5 km hr-1, 1.5% inclination) and ergometer cycling (60 watt, 60 rpm) was measured in 23 apparently healthy subjects with and without a trunk load of 10% of the body weight. For walking, the increment in energy expenditure per kg of load was 2.55 +/- 0.25 watt, while the increment per kg of body weight was 4.01 +/- 0.45 watt. For ergometer cycling, the increment per kg of load was 1.12 +/- 0.64 while that per kg of body weight was 2.73 +/- 0.56 watt. Prediction of energy expenditure for trunk loads has previously been made on the basis of the relation between energy expenditure and body weight. Our data show that this may lead to considerable overestimation.     

Modified activity-stress paradigm in an animal model of the female athlete triad.

The exercising woman with nutritional deficits and related menstrual irregularities is at risk of compromising long-term bone health, i.e., the female athlete triad. There is no animal model of the female athlete triad. The purpose of this study was to examine long-term energy restriction in voluntary wheel-running female rats on estrous cycling, bone mineral content, and leptin levels. Twelve female Sprague-Dawley rats (age 34 days) were fed ad libitum and given access to running wheels during an initial 14-wk period, providing baseline and age-related data. Daily collection included dietary intake, body weight, estrous cycling, and voluntary running distance. At 4 mo, rats were randomized into two groups, six restrict-fed rats (70% of ad libitum intake) and six rats continuing as ad libitum-fed controls. Energy intake, energy expenditure, and energy availability (energy intake - energy expenditure) were calculated for each animal. Serum estradiol and leptin concentrations were measured by RIA. Femoral and tibial bone mineral density and bone mineral content (BMC) were determined by dual-energy X-ray absorptiometry. Restrict-fed rats exhibited a decrease in energy availability during Weight Loss and Anestrous phases (P = 0.002). Compared with controls after 12 wk, restrict-fed rats showed reduced concentrations of serum estradiol (P = 0.002) and leptin (P = 0.002), lower ovarian weight (P = 0.002), and decreased femoral (P = 0.041) and tibial (P = 0.05) BMC. Decreased energy availability resulted in anestrus and significant decreases in BMC, estrogen and leptin levels, and body weight. Finally, there is a critical level of energy availability to maintain estrous cycling.     

Estimation of the amount of dietary starch available to different populations

The daily per capita availability of dietary starch was estimated for 38 selected countries using food disappearance data from the FAO provisional food balance sheets (1972-1974 average); starch availability was also estimated for Canada from 1960 to 1987 using Agriculture Canada disappearance data. Total starch availability varies fourfold among the difference countries; the availability of different sources of starch vary up to 80-fold. Wheat and roots-tubers were the major sources of starch in countries with low total starch availability. Either corn and pulses, rice and pulses, or wheat and potatoes were the major sources of starch in those countries with high total starch availability. Starch availability in Canada, both total and by source, has been relatively constant over the 27 years examined. Slight increases in total starch and starch from cereals and pulses in 1987 will need to be followed to determine whether these represent the beginning of a real change in per capita starch availability.     

Optimal rate of work for mountaineers

The physiological responses of seven young male highlanders were recorded at high altitude while they were carrying loads (0, 25, 35, 45, and 55 kg) on snow at different speeds, supporting the loads on their backs by circular straps around the forehead. The rates of work calculated from the gross weight (body weight plus actual load in kg) multiplied by the speed of walking, m.min-1, ranged from 4,460 to 8,440 kg.m.min-1. The relationship between the rate of work and energy expenditure was rectilinear within the present range of values. The oxygen consumption (51.6 and 59.7 ml.min-1.kg-1 BW) for 55-kg load (at 4.09 and 4.64 km.h-1) possibly reached maximal aerobic capacity. At higher energy output at high altitude the subjects were exhausted after a short period of work. The proportion of increase of oxygen consumption per kg gross weight carried or per kg.m was almost constant up to a 55-kg experimental load. It is suggested that for day-to-day operations work should not be undertaken at more than 30-40% of maximal work capacity; a rate of work around 4,000 kg.m.min-1 (25-30 kg actual load at 3.0 to 3.5 km.h-1) may be considered as optimal for highlanders and porters at high altitude.     

Changes in nutrient intakes of conditioned men during a 5-day period of increased physical activity and other stresses

Nutrient intakes and selected blood and urinary constituents of 16 Navy servicemen were obtained before and during a period of 113 hours of physical activity, sleep deprivation, and psychological stress, to document the dietary adaptation of physically conditioned men to an extended period of hard physical work and other stresses. Food intakes were monitored by 1-day diet records prior to and by direct observation during the period. The factorial method was used to calculate energy expenditure. Carbohydrates provided 45 and 43% of the total energy intake before and during the experiment. Protein intakes and intakes of all the vitamins and minerals studied exceeded the Recommended Dietary Allowances, both before and during the period. Total energy intake averaged 18.7 MJ.d-1 before and 24.4 MJ.d-1 during the experiment. Body weight increased significantly by 2.7 +/- 0.4 kg (mean +/- s.e.) during the experiment (p less than 0.0001). There was a significant correlation (r = 0.74; p less than 0.001) between the change in body weight and urinary sodium from before to after the experiment suggesting that increased dietary sodium may have contributed to the weight gain. A significant increase in plasma volume (11.9 +/- 3.2%; p less than 0.0003) provided further support that the observed weight gain was due to sodium intake rather than a positive energy balance. In conclusion, conditioned men increased food consumption adequately to meet increased energy demands.     

Nutrition transition and dietary energy availability in Eastern Europe after the collapse of communism.

After the economic transition of the late 1980s and early 1990s there was a rapid increase in overweight and obesity in many countries of Eastern Europe. This article describes changing availability of dietary energy from major dietary components since the transition to free-market economic systems among Eastern European nations, using food balance data obtained at national level for the years 1990-92 and 2005 from the FAOSTAT-Nutrition database. Dietary energy available to the East European nations satellite to the former Soviet Union (henceforth, Eastern Europe) was greater than in the nations of the former Soviet Union. Among the latter, the Western nations of the former Soviet Union had greater dietary energy availability than the Eastern and Southern nations of the former Soviet Union. The higher energy availability in Eastern Europe relative to the nations of the former Soviet Union consists mostly of high-protein foods. There has been no significant change in overall dietary energy availability to any category of East European nation between 1990-1992 and 2005, indicating that, at the macro-level, increasing rates of obesity in Eastern European countries cannot be attributed to increased dietary energy availability. The most plausible macro-level explanations for the obesity patterns observed in East European nations are declines in physical activity, increased real income, and increased consumption of goods that contribute to physical activity decline: cars, televisions and computers.     

Economic transition and household food consumption: A study of Bulgaria from 1985 to 2002

Major economic transitions typically entail changes in the availability of and purchasing power for different types of foods leading to long-term changes in the composition of the diet. Bulgaria, a former Eastern Bloc country, underwent a difficult and protracted transition from a centralized to market economy with acute economic crises and a much slower recovery of income levels than in Poland, the Czech Republic, and Hungary. Using annual data from the Bulgarian National Household Survey, we study changes in the reported consumption of major foods (excluding alcoholic drinks) and their constituent macronutrients from 1985 to 2002, examining also the differences in dietary patterns between the period prior to and following the transition. The consumption of most major food items decreased, resulting in a fall in per capita energy consumption of 429 kcal/day (1.80 MJ/d), following the economic transition of 1991. As expected, the consumption of foods that were more expensive per unit of energy decreased greater than cheaper foods, -34% for animal products and -19% for visible fats, but only -10% for carbohydrates. These changes are related to the changes in income and market prices as well as the general negative trend in economic growth and hyperinflation in the mid-1990s. Thus, Bulgaria experienced a decrease in food consumption without significant changes in the dietary pattern following the economic transition of 1991. The fact that part of this decline may be attributed to continued economic challenges suggests that future transitions in the diet may be expected as economic development proceeds.     

Pattern and cost of weight gain in previously obese women

Weight gain is common among postobese individuals, providing an opportunity to address the cost of weight regain on energy expenditure. We investigated the energy cost of weight regain over 1 yr in 28 women [age 39.5 +/- 1.3 (SE) yr; body mass index 24.2 +/- 0.5 kg/m(2)] with recent weight loss (>12 kg). Body composition, total energy expenditure (TEE) using doubly labeled water, resting metabolic rate (RMR), and thermic effect of a meal (TEM) were assessed at 0 and 12 mo. Metabolizable energy intake (MEI) was calculated from TEE and change in body composition. Fourteen women had a weight gain of 13.2 +/- 2.1 kg. Twelve-month cumulative excess MEI, calculated as the intake in excess of TEE at month 0, was 749 +/- 149 MJ. Of this, 462 +/- 83 MJ (62%) were stored as accrued tissue, and 287 +/- 72 MJ (38%) was increased TEE. Expressed per kilogram of body weight gain, the energy cost of weight gain was calculated to be 54.8 +/- 4.6 MJ/kg. Interestingly, weight regain time courses fell into three distinct patterns, possibly requiring varying countermeasures.     

Effects of dietary protein content on IGF-I, testosterone, and body composition during 8 days of severe energy deficit and arduous physical activity.

Energy restriction coupled with high energy expenditure from arduous work is associated with an altered insulin-like growth factor-I (IGF-I) system and androgens that are coincident with losses of fat-free mass. The aim of this study was to determine the effects of two levels of dietary protein content and its effects on IGF-I, androgens, and losses of fat-free mass accompanying energy deficit. We hypothesized that higher dietary protein content would attenuate the decline of anabolic hormones and, thus, prevent losses of fat-free mass. Thirty-four men [24 (SD 0.3) yr, 180.1 (SD 1.1) cm, and 83.0 (SD 1.4) kg] participated in an 8-day military exercise characterized by high energy expenditure (16.5 MJ/day), low energy intake (6.5 MJ/day), and sleep deprivation (4 h/24 h) and were randomly divided into two dietary groups: 0.9 and 0.5 g/kg dietary protein intake. IGF-I system analytes, androgens, and body composition were assessed before and on days 4 and 8 of the intervention. Total, free, and nonternary IGF-I and testosterone declined 50%, 64%, 55%, and 45%, respectively, with similar reductions in both groups. There was, however, a diet x time interaction on day 8 for total IGF-I and sex hormone-binding globulin. Decreases in body mass (3.2 kg), fat-free mass (1.2 kg), fat mass (2.0 kg), and percent body fat (1.5%) were similar in both groups (P = 0.01). Dietary protein content of 0.5 and 0.9 g/kg minimally attenuated the decline of IGF-I, the androgenic system, and fat-free mass during 8 days of negative energy balance associated with high energy expenditure and low energy intake.     

Effects of fermentable starch and straw-enriched housing on energy partitioning of growing pigs

Both dietary fermentable carbohydrates and the availability of straw bedding potentially affect activity patterns and energy utilisation in pigs. The present study aimed to investigate the combined effects of straw bedding and fermentable carbohydrates (native potato starch) on energy partitioning in growing pigs. In a 2 × 2 factorial arrangement, 16 groups of 12 pigs (approximately 25 kg) were assigned to either barren housing or housing on straw bedding, and to native or pregelatinised potato starch included in the diet. Pigs were fed at approximately 2.5 times maintenance. Nitrogen and energy balances were measured per group during a 7-day experimental period, which was preceded by a 30-day adaptation period. Heat production and physical activity were measured during 9-min intervals. The availability of straw bedding increased both metabolisable energy (ME) intake and total heat production (P < 0.001). Housing conditions did not affect total energy retention, but pigs on straw bedding retained more energy as protein (P < 0.01) and less as fat (P < 0.05) than barren-housed pigs. Average daily gain (P < 0.001), ME intake (P < 0.001) and energy retention (P < 0.01) were lower in pigs on the native potato starch diet compared to those on the pregelatinised potato starch diet. Pigs on the pregelatinised potato starch diet showed larger fluctuations in heat production and respiration quotient over the 24-h cycle than pigs on the native potato starch diet, and a higher activity-related energy expenditure. The effect of dietary starch type on activity-related heat production depended, however, on housing type (P < 0.05). In barren housing, activity-related heat production was less affected by starch type (16.1% and 13.7% of total heat production on the pregelatinised and native potato starch diet, respectively) than in straw-enriched housing (21.1% and 15.0% of the total heat production on the pregelatinised and native potato starch diet, respectively). In conclusion, the present study shows that the availability both of straw bedding and of dietary starch type, fermentable or digestible, affects energy utilisation and physical activity of pigs. The effects of housing condition on protein and fat deposition suggest that environmental enrichment with long straw may result in leaner pigs. The lower energy expenditure on the physical activity of pigs on the native potato starch diet, which was the most obvious in straw-housed pigs, likely reflects a decrease in foraging behaviour related to a more gradual supply of energy from fermentation processes.     

Evidence for an intrinsic energetic ceiling in free-ranging kittiwakes Rissa tridactyla

1. The rate at which free-living animals can expend energy is limited but the causes of this limitation are not well understood. Theoretically, energy expenditure may be intrinsically limited by physiological properties of the animal constraining its capacity to process energy. Alternatively, the limitation could be set extrinsically by the amount of energy available in the environment or by a fitness trade-off in terms of reduced future survival associated with elevated metabolism.
2. We measured daily energy expenditure (DEE) using the doubly labelled water method in chick-rearing black-legged kittiwakes ( Rissa tridactyla ) at a study site close to the northern limit of their breeding range over 5 years. We measured breeding success, foraging trip duration and diet composition as proxies of resource availability during these years and estimated the probability of parent kittiwakes to return to the colony in relation to their energy expenditure in order to determine whether kittiwakes adjust their DEE in response to variation in prey availability and whether elevated DEE is associated with a decrease in adult survival.
3. We found that DEE was strikingly similar across all five study years. There was no evidence that energy expenditure was limited by resource availability that varied considerably among study years. Furthermore, there was no evidence of a negative effect of DEE on adult return rate, which does not support the hypothesis of a survival cost connected to elevated energy expenditure.
4. The additional lack of variation in DEE with respect to ambient temperature, brood size or between sexes suggests that kittiwakes at a time of peak energy demands may operate close to an intrinsic metabolic ceiling independent of extrinsic factors.     

Declining body size in an endangered large mammal

Body size affects almost every aspect of the biology of a species. According to the ‘resource rule’, decreasing resource availability (e.g. prey density) will lead to a reduction in body size or, alternatively, a decline in mass‐independent energy expenditure. In the present study, we provide a test of this hypothesis, assessing the effect of significantly decreasing prey density on endangered African wild dog (Lycaon pictus) body size and energy expenditure over a 20‐year period. As predicted from the ‘resource rule’, decreasing resource availability resulted in energetic re‐allocation: wild dogs' body size decreased significantly (both shorter and slimmer), whereas our fitness‐related measure of energy expenditure (i.e. litter size) remained constant over time. A phenotypic change of up to 17% within 20 years, as found in the present study, appears to be unprecedented in a nonharvested large mammal, thus advancing the emerging field of eco‐evolutionary dynamics. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 8–12.     

Adaptation of energy metabolism in under-fed ruminants. Quantification in the whole animal and body tissues]

Ruminants respond to underfeeding by a progressive adaptation until a new equilibrium between dietary supply and requirements is reached. The resulting drop in maintenance energy requirements originates from a decrease in basal metabolism that depends on the level and duration of undernutrition. These modifications are not totally accounted for by changes in live weight but might be explained by differential changes in individual tissue weight and metabolism. Tissues contribute to whole animal expenditure in a disproportionate manner relative to their weight. Thus digestive tract, liver and muscle masses contribute 5-11, 1-2.5 and 35-50% to live weight but about 16-29, 17-31 and about 16% to whole animal energy expenditure, respectively, because of differences in tissue metabolic activity. Underfeeding results in a decrease in the contribution of viscera to energy expenditure, whereas results on muscle mass are scarce. These changes in contribution are due to changes in tissue mass, nutrient supply (blood flow) and/or in metabolic activity.     

Food Consumption and Nutrient Flows: Nitrogen in Sweden Since the 1870s

Changes in food consumption and related processes have a significant impact on the flow of nitrogen in the environment. This study identifies both flows within the system and emissions to the hydrosphere and atmosphere. A case study of an average inhabitant of the city of Linköping, Sweden, covers the years 1870, 1900, 1950, and 2000 and includes changes in food consumption and processing, agricultural production, and organic waste handling practices. Emissions to the hydrosphere from organic waste handling increased from 0.57 kilograms of nitrogen per capita per year (kg N/cap per year) to 3.1 kg N/cap per year, whereas the total flow of nitrogen to waste deposits grew from a negligible amount to 1.7 kg N/cap per year. The largest flow of nitrogen during the entire period came from fodder. The input of chemical fertilizer rose gradually to a high level of 15 kg N/cap per year in the year 2000. The total load per capita disposed of to the environment decreased during these 130 years by about 30%.     

Social structure and energy efficiency: A preliminary cross-national analysis

This study questions the assumption that there is an immutably positive relationship between per capita GNP and per capita energy consumption among human societies. A ratio of per capita GNP to per capita energy consumption ($U.S./kg coal equivalent) is proposed as a measure of energy efficiency for a cross-national analysis of 118 world nation-states and a subset of 25 developed market economies. This ratio is found to vary considerably, between 0.19 and 9.80. A review of literature suggests possible relationships among several sociodemographic characteristics of nations and levels of efficiency with which energy is converted into goods and services. Among the total sample, level of production (measured in terms of per capita GNP) bears a substantial inverse association with energy efficiency. When per capita GNP is held constant, agricultural share of gross domestic product and percentage of labor force in agriculture continue to be positively associated with energy efficiency among the total sample. Variables measuring defense expenditure, urbanization, and population density exhibit somewhat smaller multivariate relationships with energy efficiency when per capita GNP is controlled, i.e., these variables have significant multivariate parameters, but are less closely related to energy efficiency than level of production and agricultural composition of the economy and labor force. Agricultural composition of the economy and labor force is the major predictor of energy efficiency among the subset of 25 developed market economies. The results suggest that among the developed industrial societies level of production is less important than the composition of production activities in determining aggregate energy efficiency.This paper was originally presented at the annual meeting of the North Central Sociological Association, Pittsburgh, Pennsylvania, May 1977. This research was supported by funds from the Michigan Agricultural Experiment Station, the Ohio Agricultural Research and Development Center, and the National Research Council, National Academy of Sciences.     

Response of chicks to two diets of differing energy levels under conditions of brooding with or without supplemental heat

A 2×2 factorial experiment was conducted to determine the performance and certain physiological parameters of 200 day-old chicks fed diets containing either 2600 or 3000 kcal metabolizable energy (ME) per kilogram for a period of 28 days under conditions of brooding with or without supplemental heat in a hot humid tropical area. The results indicated that within each dietary energy level, there was no significant difference in growth rates of chicks brooded with or without supplemental heat, however, the high energy diet significantly (P<0.01) promoted greater weight gains than the low energy diet. Brooding chicks with supplemental heat and with the high energy diet, decreased feed intake and improved feed conversion efficiency. Chicks brooded without supplemental heat consumed significantly (P<0.01) less water than those brooded with heat, irrespective of the dietary energy level. Mortality and blood glucose levels were not affected by the heat and dietary energy treatments. Thyroid weight expressed as percentage of body weight, haemoglobin and hematocrit values were significantly (P<0.01) higher for chicks brooded without supplemental heat. On the other hand, dietary energy levels did not exert any effect on these physiological parameters. No significant heat and dietary energy level interaction effects were noted on all the parameters considered under this trial.     

Calorimetric measurements made on rats during repeated periods of weight gain and weight loss

1. Rats in respiration chambers were grown for 32 days and their weight reduced by 27-40% on three occasions and realimentated. After the first cycle rats lost body weight more rapidly and regained that weight more quickly than previously. 2. The initial growth phase took 32 days compared with only 8 days in the final period. Each gram of weight gain was associated with 13-14 kJ of dietary net energy during the last two periods of realimentation compared with 19-20 kJ during the first period. 3. Calorimetric measurements showed that although maintenance energy requirement increased during the periods of growth, mean net availability of metabolizable energy was 0.91 compared to 0.60 during weight loss. 4. During the final period much of the weight gain was in the form of lean (67%) but the majority of energy retained was as fat (67-70%).     

Decline in energy storage in the Antarctic minke whale (<Emphasis Type="Italic">Balaenoptera bonaerensis</Emphasis>) in the Southern Ocean

The annual trend in energy storage in the Antarctic minke whale was examined using catch data from all 18 survey years in the Japanese Whale Research Program (JARPA). Regression analyses clearly showed that blubber thickness, girth and fat weight have been decreasing for nearly 2 decades. The decrease per year is estimated at approximately 0.02 cm for mid-lateral blubber thickness and 17 kg for fat weight, corresponding to 9% for both measurements over the 18-year period. Furthermore, “date”, “extent of diatom adhesion”, “sex”, “body length”, “fetus length”, “latitude”, “age” and “longitude” were all identified as partially independent predictors of blubber thickness. The direct interpretation of this substantial decline in energy storage in terms of food availability is difficult, since no long-term krill abundance series is available. However, an increase in the abundance of krill feeders other than minke whales and a resulting decrease in the krill population must be considered as a likely explanation.     

The ecology of young turbot, Scophthalmus maximus (L.), at Borth, Cardiganshire, Wales

The ecology of 0- and 1-group turbot was studied at Borth, Cardiganshire, during the years 1966–68. Newly-metamorphosed turbot appeared in the surf zone from July to October, Abundance during the period September 1967 to May 1968 decreased at an average rate of 25% of the sampled population per month. Fish of the 1966 year-class grew from a mean length of 4.5 cm in September 1966 to 14.4 cm in October 1967. Growth was fast in the spring and summer, slowing during the late autumn and winter. The most important food items of 0- and 1-group turbot by percentage occurrence and dry weight were polychaetes and mysids. The daily food intake of 0-group turbot in September 1967 was estimated as 2.5 % of the body weight per day.