Relative Energy Intake Research Articles

24 Hr Energy Intake After A Single Exercise Session In Restrained And Unrestrained Overweight Women

At rest energy intake (EI) is expected to be lower in restrained than unrestrained eaters. It is unknown however how acute exercise affects appetite and EI in restrained and unrestrained overweight/obese women. PURPOSE: To investigate acute effects of exercise on EI between restrained and unrestrained overweight/obese women. METHODS: Sedentary and overweight/obese women completed one exercise and one control trial following a crossover design. Trials were randomly counterbalanced and of 24h duration each (including overnight at home). Weighed EI record was kept for 2.5 days before 1st trial and was replicated before 2nd trial. In the exercise trial subjects completed an aerobic exercise session at 65% VO2max intensity to expend 1.67MJ. In the control trial subjects rested quietly for the same duration. Appetite was measured throughout trials using visual analogue scale (Flint et al, 2000). Absolute and relative EI (REI) were measured during 3 buffet meals served throughout each trial (day 1 post-intervention dinner and day 2 breakfast and lunch) with covert observation of EI. Cognitive restraint of eating was measured using the 3 factor eating questionnaire and the median restraint score was used for classification. Data were compared by paired and 2 sample t-test. RESULTS: 15 subjects completed the trials, with no attrition. 8 subjects were restrained (R) and 7 unrestrained (UR). Mean values of physical characteristics were not different between groups and trials (Weight (kg): 75.1 ± 10.4 (R), 79.2 ± 12.8 (UR); BMI (kg/m2): 29.5 ± 3.0 (R) 30.7 ± 2.1 (UR); Mean ± SD). Average energy cost of exercise (minus metabolic costs) was not different between groups (R: 1.85 ± 0.27; UR: 1.57 ± 0.25 MJ). No difference between trials and groups was found in subjective ratings of appetite. 24hr EI and REI was not significantly different between groups in either trial. However, REI of UR was significantly lower after exercise than control trial (Ex: 8.52 ± 1.94; Con: 9.96 ± 2.42 MJ/24hrs, p<0.05), while there was no difference in the EI of R between trials. CONCLUSIONS: These novel and preliminary findings suggest that EI in UR females may be affected by a single exercise session while EI in R females remains relatively constant. This may reflect differing levels of cognitive restraint. Further studies are required to confirm these pilot data.

Acute effect of environmental temperature during exercise on subsequent energy intake in active men

BackgroundThe performance of exercise while immersed in cold water has been shown to influence energy intake in the subsequent meal. However, the effect of ambient temperature during land-based exercise is not known. ObjectivesOur aims were to investigate the effect of exercise performed in the heat on energy intake in the subsequent meal and to determine concentrations of circulating appetite-related hormones. DesignIn a randomized, counterbalanced design, 11 active male participants completed 3 experimental trials in a fasted state: exercise in the heat (36°C), exercise in a neutral temperature (25°C), and a resting control (25°C). The exercise trials consisted of treadmill running for 40 min at 70% ▪O2peak. After each trial, participants were presented with a buffet-type breakfast of precisely known quantity and nutrient composition, which they could consume ad libitum. ResultsEnergy intake was greater after exercise in the neutral temperature compared with the control (P = 0.021) but was similar between exercise in the heat and the control and between the 2 exercise trials. When accounting for the excess energy expended during exercise, relative energy intake during exercise in the heat was lower than the control (P = 0.002) but was similar between exercise in the neutral temperature and the control and between exercise in the heat and in the neutral temperature. The lower relative energy intake after exercise in the heat was associated with an elevated tympanic temperature and circulating concentrations of peptide YY (P < 0.05). ConclusionExercise in a neutral environmental temperature is associated with higher energy intake in the subsequent meal compared with a control, whereas exercise in the heat is not.

Effect of resistance exercise, with or without carbohydrate supplementation, on plasma ghrelin concentrations and postexercise hunger and food intake

The effects of resistance exercise with and without carbohydrate (CHO) supplementation on hunger, postexercise food intake, and plasma ghrelin, an orexigenic gastric peptide, are poorly characterized. We examined the individual and combined effects of a resistance exercise bout and CHO consumption on plasma ghrelin and postexercise food intake. Twenty-one apparently healthy young male participants ([mean ± SD] age = 20 ± 1.8 years, body mass index = 24.8 ± 3.3 kg/m 2) completed in random order 3 treatment conditions: (1) ExCHO—80-minute resistance exercise bout while consuming CHO (∼77 g CHO, 306 kcal); (2) ExPLA—identical exercise with a noncaloric placebo; and (3) NoExCHO—no-exercise trial of quiet sitting and CHO consumption. Blood samples were obtained before, during, and immediately postexercise, and 110 minutes after exercise. At 2 hours postexercise, they were provided a buffet of food from which they ate ad libitum. There was a significant time × treatment interaction for plasma ghrelin caused by a decline from pre- to postexercise in the 2 exercise conditions compared with an increase over time in the NoExCHO condition. At 110 minutes postexercise, ghrelin was 21% and 13% lower in ExCHO and ExPLA compared with NoExCHO (both Ps < .05). However, despite the lower ghrelin concentrations for the 2 exercise conditions, the subjective ratings of hunger were not lower for these conditions compared with the NoExCHO. There were no differences in absolute ad libitum energy intake from the buffet among the 3 conditions, but relative energy intake from the buffet accounting for the estimated cost of exercise was lowest among the 2 exercise conditions. We conclude that (1) weight lifting lowers plasma ghrelin concentrations during exercise and attenuates its rise during the postexercise period in young men and (2) the lower plasma ghrelin concentration is not associated with lower subjective feelings of hunger measured 100 minutes postexercise, but is associated with a lower relative food intake.

Preoperative protein and energy intake and postoperative complications in well-nourished, non-hospitalized elderly cardiac surgery patients

Little is known about the impact of preoperative protein or energy intake in relation to the occurrence of postoperative complications in patients who are not undernourished but cannot keep up their daily protein or energy requirements prior to cardiac surgery. Therefore, a prospective study on intake in preoperatively well-nourished, non-hospitalized cardiac surgery patients (>or= 65 y) was carried out. Between December 2004 and November 2005 preoperative protein and energy intake and postoperative outcome data were collected from 100 consecutive patients undergoing cardiac surgery. Comparison of low protein intake (<or= 0.98 g/kg/d) with high protein intake (>0.98 g/kg/d) showed a low protein intake did not result in more complications or prolonged length of stay. In low-risk operation patients in particular, a high-energy intake (>22 kcal/kg/d) resulted in more postoperative complications than a low energy intake (<or= 22 kcal/kg/d) (33.3% and 13.2%, respectively; (OR 5.0 95% CI [1.5-16.9])). A preoperative protein intake <or= 0.80 g/kg/d was seen in 22.6%, and an energy intake <or= 25 kcal/kg/d in 72.2% of the patients. The outcome of this study suggests that detecting and correcting a preoperative low protein or energy intake is of no clinical relevance in the well-nourished, non-hospitalized elderly cardiac surgery patients. Caloric overfeeding may be associated with an increased complication rate.

Changes in gut hormone levels and negative energy balance during aerobic exercise in obese young males

We examined whether changes in gut hormone levels due to a single bout of aerobic exercise differ between obese young males and normal controls, and attempted to determine the involvement of hormonal changes during exercise in the regulation of energy balance (EB) in these obese subjects. Seven obese and seven age-matched subjects of normal weight participated in exercise and rest sessions. Subjects consumed a standardized breakfast that was followed by constant cycling exercise at 50% VO(2max) or rest for 60 min. At lunch, a test meal was presented, and energy intake (EI) and relative energy intake (REI) were calculated. Blood samples were obtained at 30 min intervals during both sessions for measurement of glucose, insulin, glucagon, ghrelin, peptide YY (PYY), and glucagon-like peptide-1 (GLP-1). Plasma levels of PYY and GLP-1 were increased by exercise, whereas plasma ghrelin levels were unaffected by exercise. The areas under the curve (AUC) of the time courses of PYY and GLP-1 levels did not significantly differ between the two groups. In contrast, EI and REI were decreased by exercise in both groups, and energy deficit was significantly larger in obese subjects than in normal controls. The present findings suggest that short-term EB during a single exercise session might be regulated not by increased amounts of these gut hormones per se.

Effects of body weight and temperature on feed intake, gonad growth and oxygen consumption in green sea urchin, Strongylocentrotus droebachiensis

The current study describes the metabolic performance of adult green sea urchin Strongylocentrotus droebachiensis in terms of oxygen consumption, feed intake and gonad growth in relation to body weight and temperature. The experiments were conducted at six constant temperatures (4, 6, 8, 10, 12 and 14 °C), and with three body size groups, i.e. small (S, 40 g), medium (M, 65 g), and large (L, 100 g). Results show that 10–12 °C is the optimum temperature for gonad growth for 40–100-g green sea urchin during summer/autumn, and that there is an inverse relationship between optimum temperature and size. Contrary to gonad growth, both feed intake and oxygen consumption continued to increase throughout the entire temperature range (4–14 °C). The Q 10 values for oxygen consumption of fed animals were in the normal range (1.72–3.01), while the corresponding values for starved animals were low (1.17–1.36), indicating negligible effects of temperature on aerobic metabolism during starvation. The energetic analyses indicate a poorly developed regulation of energy intake in relation to energy expenditure. The oxygen consumption data from this study can, together with a still missing description of the relationship between oxygen saturation and somatic and gonad growth, be used to evaluate the water requirement of green sea urchin in aquaculture.

Physical Activity Is Associated with Risk Factors for Chronic Disease across Adult Women's Life Cycle

Objective The purpose of this study was to examine the association of age (young, midlife, and older) and activity level (active and sedentary), determined by a pedometer, with risk factors of chronic disease, including body composition, dietary intake, serum lipids, insulin, leptin, C-reactive protein (CRP), plasma glucose, and resting metabolic rate (RMR) in women across the adult life cycle. Methods Young (aged 20 to 30 years) (n=49), midlife (aged 40 to 50 years) (n=62), and older (aged 60 years and older) (n=47) women were recruited for this cross-sectional study. For 7 days, participants completed weighed food records and wore a pedometer. Based on the average number of steps per day, the women were further classified as active (≥7,500 steps per day) or sedentary (<7,500 steps per day). Height, weight, and waist circumference were determined for each participant. Fasting blood samples were taken to assess serum lipid, CRP, insulin, leptin, thyroid stimulating hormone, and plasma glucose levels. RMR and body composition (via dual-energy x-ray absorptiometry) were assessed. Results Young and midlife women had lower concentrations compared to older women for serum cholesterol ( P<0.01), low-density lipoprotein cholesterol ( P<0.01), triglycerides ( P<0.01), leptin ( P<0.01), and plasma glucose ( P<0.01); midlife women had lower serum insulin concentrations vs young and older groups ( P=0.01); young women had smaller waist circumference compared to midlife and older groups ( P<0.01); percent body fat ( P<0.01) and percent fat-free mass ( P<0.01) differed between all ages. Lower values were found in active vs sedentary women for serum insulin ( P=0.02), serum leptin ( P<0.01), waist circumference ( P<0.01) and percent body fat ( P<0.01). A higher percent fat-free mass ( P<0.01) was also found in active compared to sedentary women. No differences were found between activity groups for serum cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, CRP, plasma glucose levels, or RMR. RMR was higher in young and midlife vs the older women ( P<0.01). Significant inverse correlations were found between activity (steps per day) and body mass index, insulin level, CRP concentration, leptin level, waist circumference, and body fat. Significant positive correlations were found between age and body mass index, total serum cholesterol level, low-density lipoprotein cholesterol level, serum triglyceride level, leptin level, plasma glucose level, CRP concentration, waist circumference, and body fat. Young and midlife women reported consuming more relative energy (kilocalories per kilogram body weight) and protein (grams per kilogram body weight) than older women ( P<0.01). The midlife women reported consuming more dietary cholesterol compared to the young and older women ( P<0.01). Active women reported a higher relative energy (kilocalories per kilogram body weight) and protein (grams per kilogram body weight) intake vs the sedentary women ( P<0.01). Active women also reported a higher intake of dietary carbohydrates (grams per day, P<0.01; percent of energy, P=0.04). Conclusions Overall, these results indicate that younger age and greater physical activity, despite age, are associated with fewer risk factors for chronic disease, such as cardiovascular disease, type 2 diabetes, and obesity.

Improved Nutrition During Nocturnal Hemodialysis

Nocturnal home hemodialysis (NHHD, 6x8 hours/week) is a most effective treatment, resulting in better clinical outcome than standard 3 x weekly hemodialysis. We studied the efffects of NHHD on nutritional intake. Fifteen stable dialysis patients completed a food diary for 5 days while on standard hemodialysis (base line), and for 3 days 3, 6 and 12 months after starting NHHD. Three patients received a renal transplant during the study period and one did not complete the diaries. Therefore, data in 11 patients could be analysed using an ANOVA. During one year NHHD, body weight increased from 70+4.6 to 75+5.2 kg (M+SEM) (p<0.001) and energy intake by 6% (NS). Relative energy intake remained constant (33+ 3.5 kcal/kg). Protein intake increased by 25% (p=0.001) to 1.34+0.13 g/kg. Phosphate (P) intake increased by 24% (p<0.001), while serum P normalised despite the cessation of phosphate binding agents in all but 2 patients. Calcium intake from food sources increased by 29% (p<0.001), but calcium intake from phosphate binding agents decreased significantly. Potassium intake increased by 24% to 3200+960 mg/d (p=0.002) and water intake by 29% to 2.0+0.6liter (p<0.001). The intake of dairy products was increased by 41% (p=0.042), meat and fish by 47% (p=0.015) and potatoes, vegetables and fruit by 41% (p=0.04). The adequacy of dialysis, measured by Kt/V, increased from 2.58 +0.23 to 8.30+0.79, p<0.001. During NHHD, body weight and intake of protein, P, Ca, K and water as well as dairy products, meat and vegetables increase, suggesting an improved nutritional state.

Estimating expenditure on male and female offspring in a sexually size‐dimorphic bird: a comparison of different methods

The parents of sexually size-dimorphic offspring are often assumed to invest more resources producing individuals of the larger sex. A range of different methods have been employed to estimate relative expenditure on the sexes, including quantifying sex-specific offspring growth, food intake, energy expenditure and energy intake, in addition to measures of parental food provisioning and energy expenditure. These methods all have the potential to provide useful estimates of relative investment, but each has particular problems of interpretation, and few studies have compared the estimates derived concurrently from more than two of these measures. In this study we compared these surrogate measures of parental investment in the brown songlark Cinclorhamphus cruralis, which exhibits one of the most extreme cases of sexual size dimorphism among birds. At 10 days of age we found that male chicks, on average, were 49% heavier, received 42% more prey items, expended 44% more energy and ingested 50% more metabolizable energy than their sisters. Furthermore, we created, experimentally, both all-male and all-female broods of 10-day-old chicks and found that mothers delivered 43% more prey items and expended 27% more energy when provisioning all-male broods, providing the first direct evidence for a change in parental energy expenditure in relation to brood sex ratio. These data reveal remarkable agreement between these estimates of investment and suggest that all may provide quantitatively useful information on sex allocation. However, the lower variance associated with estimates of relative mass and energy intake suggest that these methods may be of greater utility, although this may primarily reflect the shorter period over which our provisioning data were collected.

Nutritional status of adventure racers

Objective We describe the usual food intake, body composition, and biochemical profile of adventure racers during their training season and evaluate their energy and nutrient intake in relation to current recommendations for ultraendurance athletes. Methods Twenty-four adventure race athletes (18 men and 6 women), 24 to 42 y of age, participated in the study. Food intake was determined with a 3-d food record and body composition by plethysmography. Blood samples were obtained from all subjects for biochemical analyses. All assessments were made during the usual training phase. Results Female athletes had a higher body fat percentage than did male athletes (20.2 ± 5.7% versus 12.5 ± 3.5%). For men and women, food intake was high in protein (1.9 ± 0.5 g/kg in men, 2.0 ± 0.4 g/kg in women) and fat (1.6 ± 0.3 g/kg in men, 1.5 ± 1.3 g/kg in women). Carbohydrate intake of male athletes was at the lower limit of that recommended (5.9 ± 1.8 g/kg). For most vitamins and minerals, athletes’ intake was adequate, with the exception of magnesium, zinc, and potassium in men and women and vitamin E and calcium in women, which presented a high probability of being inadequate compared with reference values. High blood levels of total cholesterol and low-density lipoprotein cholesterol were found in female athletes (201.0 ± 44.7 and 104.1 ± 43.1 mg/dL, respectively) and all other biochemical analyses were within normal reference values. Conclusion The adventure racers presented an inadequate nutritional profile when compared with recommendations for endurance exercise. These athletes need to be educated about consuming an adequate diet to meet the nutritional needs of their activity.

Optimizing rumen functions in the close-up transition period and early lactation to drive dry matter intake and energy balance in cows

The large deficit in energy intake in relation to energy requirements during the transition and early lactation periods means that high-producing cows need energy-dense rations. High-starch diets are intensively fermented by the microbial ecosystem in the rumen, giving rise to a high production of VFAs and resulting in a drop in pH and the accumulation of lactic acid, which exacerbates the decline in pH and is considered as the major cause of rumen acidosis. This rumen dysfunction affects rumen microbes and results in less efficient digestion, thereby decreasing feed intake and exacerbating the energy deficit in the cows. The main way to limit the risk of acidosis is by diet management. Thus, animals must be progressively adapted to grain ingredients during the 3-week period before calving. Furthermore, the diet management strategy will be to privilege low-degradable starch and include enough fiber in the diet to stimulate rumination and salivation. Chemical additives can be used to prevent rumen acidosis. Rumen pH can be controlled by direct addition of chemical buffers at doses of 1–2% of DM intake. Metabolic hydrogen can be mobilized through specific metabolic pathways such as propionogenesis to compete with the synthesis of lactic acid. This can be achieved by adding propionate precursors such as aspartate, malate or fumarate. However, these additives are not economically viable, and will not easily be accepted by consumers. Probiotics, which are mainly supplied as live yeasts, have to be regarded as a solution for preventing subacute acidosis but they are not considered as an efficient cure for acute acidosis. Although the mechanisms of action of probiotics are not fully understood, this paper proposes a plausible model of their mode of action. Recently, additives based on plant extracts have been proposed as a solution for optimizing rumen functions, but further efficacy studies and safety trials are required before these additives can be marketed. The addition of fibrolytic enzymes has been suggested to improve the digestion of the dietary fiber fraction during acidosis. Although the results obtained so far are encouraging, more ruminant-specific research needs to be carried out on these enzymes. Some antibiotics are potential inhibitors of Gram-positive bacteria, which are involved in rumen acidosis, but their use as feed additives has been banned from 01/01/2006 in the EU.

Appetite sensations as a marker of overall intake

The aim of this study was to evaluate the clinical utility of appetite sensations to characterize individual overall energy intake. A group of men (n 28) and women (n 23) was recruited to record their 'desire to eat', 'hunger', 'fullness' and 'prospective food consumption' (PFC) on visual analogue scales before a standardized meal test, immediately after and every 10 min for a period of 1 h after the meal. The 1 h post-meal area under the curve (1 h AUC) and the satiety quotient (SQ) were calculated for all appetite sensations. In a second visit, all participants were invited to eat three meals in order to measure total energy intake (TEI) and food preferences. Metabolic rate (MR) was also assessed to derive daily relative energy intake (REI) by subtracting this variable from TEI (TEI-MR=REI). The Three-Factor Eating Questionnaire scores were also calculated for all participants. One h AUC for fullness was the appetite sensation most strongly associated with TEI and REI (r-0.42, P< or =0.003 and r-0.32, P< or =0.05, respectively). SQ for fullness was the only predictor of TEI and REI (r-0.42, P< or =0.0003 and r-0.30, P< or =0.05, respectively). Restraint, disinhibition and hunger scores were not associated with appetite sensation variables. These results suggest that the fullness dimension seems to be a useful appetite sensation to predict long-term TEI and REI. Thus, assessment of appetite sensation such as fullness in response to a fixed load may be useful to evaluate individual overall energy intake.

Effects of exercise intensity on food intake and appetite in women

Increasing exercise intensity has been shown to reduce energy intake in men. The main objective of this study was to investigate the effects of exercise intensity on energy intake in women. Thirteen moderately active (peak oxygen uptake: 44.0 +/- 4.7 mL . kg(-1) . min(-1)) women [body mass index (in kg/m(2)): 22.2 +/- 2.4; age: 22.2 +/- 2.0 y] were subjected to 3 experimental conditions: control with no exercise and 2 equicaloric (350 kcal) low- (LIE) and high- (HIE) intensity exercise sessions at 40% and 70% of peak oxygen uptake, respectively. After each session, the participants ate ad libitum from buffet-type meals at lunch and dinner and ate snacks during the afternoon and evening. Visual analogue scales were used to rate appetite. More energy was ingested at lunchtime after the HIE session than after the control session (878 +/- 309 and 751 +/- 230 kcal, respectively; P = 0.02). Relative energy intake (postexercise energy intake corrected for the energy cost of exercise above the resting level) at lunch was lower after the LIE session than after the control session (530 +/- 233 and 751 +/- 230 kcal, respectively; P < 0.001) and was lower after the HIE session than after the control session (565 +/- 301 and 751 +/- 230 kcal, respectively; P < 0.01). Similarly, daily energy intake tended to increase during the HIE session relative to that during the control session. No treatment effect was found for appetite scores throughout the experiment. The results suggest that HIE increases energy intake in women.

S 23521 Decreases Food Intake and Body Weight Gain in Diet‐Induced Obese Rats

To investigate the effect of S 23521, a new glucagon-like peptide-1-(7-36) amide analogue, on food intake and body weight gain in obese rats, as well as on gene expression of several proteins involved in energy homeostasis. Lean and diet-induced obese rats were treated with either S 23521 or vehicle. S 23521 was given either intraperitoneally (10 or 100 microg/kg) or subcutaneously (100 microg/kg) for 14 and 20 days, respectively. Because the low-dose treatment did not affect food intake and body weight, the subcutaneous treatment at high dose was selected to test the effect on selected end-points. Treated obese rats significantly decreased their cumulative energy intake in relation to vehicle-treated counterparts (3401 +/- 65 vs. 3898 +/- 72 kcal/kg per 20 days; p < 0.05). Moreover, their body weight gain was reduced by 110%, adiposity was reduced by 20%, and plasma triglyceride levels were reduced by 38%. The treatment also improved glucose tolerance and insulin sensitivity of obese rats. Regarding gene expression, no changes in uncoupling protein-1, uncoupling protein-3, leptin, resistin, and peroxisome proliferator-activated receptor (PPAR)-gamma were observed. S 23521 is an effective glucagon-like peptide-1-(7-36) amide analogue, which induced a decrease in energy intake, body weight, and adiposity in a rat model of diet-induced obesity. In addition, the treatment also improved glucose tolerance and insulin sensitivity of obese rats. These results strongly support S 23521 as a putative molecule for the treatment of obesity.

CB1 cannabinoid receptor knockout in mice leads to leanness, resistance to diet-induced obesity and enhanced leptin sensitivity.

There is growing evidence for an implication of the CB1 receptor subtype of the endocannabinoid system in the regulation of eating and fat deposition. To further define the physiological role of these receptors in the control of energy balance, we characterized the phenotype of CB1 receptor knockout (CB1(-/-)) mice maintained on an obesity-prone regimen or on a standard chow. CB1(-/-) male mice were compared to wild-type animals (CB1(+/+) male mice) in two feeding paradigms: (1) with a standard laboratory regimen (3.5 kcal/g, 14.5% of energy as fat) and (2) on a free-choice paradigm consisting of offering both the standard laboratory chow and a high-fat diet (HFD) (4.9 kcal/g, 49% of energy as fat). When maintained on the standard diet, CB1(-/-) mice are lean. At the age of 20 weeks, their body weight and adiposity are, respectively, 24 and 60% lower than that of CB1(+/+) mice. They are slightly hypophagic, but when expressed as percent of body weight, their relative energy intake is similar to that of the wild-type animals. Furthermore, inactivation of CB1 receptors reduces plasma insulin and leptin levels, and enhances the response to intracerebroventricular leptin injection. The free-choice paradigm shows that the preference for a high-fat highly palatable chow is slightly delayed in onset but maintained in CB1(-/-) mice. However, loading CB1(-/-) mice with this obesity-prone diet does not result in development of obesity. Knockout mice do not display hyperphagia or reduction of their relative energy intake in contrast to CB1(+/+) mice, and their feeding efficiency remains low. These data suggest an improved energetic metabolism with the high-fat regimen. Furthermore, the insulin resistance normally occurring in HFD-fed mice is not present in CB1(-/-) mice. These results provide evidence that the stimulation of CB1 receptors is a key component in the development of diet-induced obesity, and that these receptors and their endogenous ligands are implicated not only in feeding control but also in peripheral metabolic regulations. The lack of effect of SR141716, a selective CB1 receptor antagonist, in CB1(-/-) mice further supports this hypothesis, as this compound was previously shown to display potent anti-obesity properties in diet-induced obese C57BL/6 mice.

ENERGY INTAKE, EXPENDITURE, AND AVAILABILITY IN YOUNG FEMALE RATS WITH ACCESS TO VOLUNTARY EXERCISE

The prevalence of menstrual disorders in the exercising female continues to be a major concern. Reproductive function is altered more frequently in women who exercise strenuously and maintain stringent weight goals. Similar patterns of ovulatory dysfunction due to exercise training have also been reported in laboratory rats. PURPOSE The purpose of this study was to examine age-related patterns of ad libitum intake, voluntary exercise, and energy availability in young ovulating female rats. METHODS Diet intake, body weight (BW), estrous cycling, and voluntary running distance was determined in 12 female Sprague Dawley rats during a 14-week trial. To assess the relative availability of energy (kcal/gm BW), differences in energy intake versus expenditure were determined. Energy intake was calculated at 3.8 kcal/gm diet consumed, and total energy expenditure was based on both the maintenance energy requirement (ME) of laboratory rats (112 kcal/BWkg 0.75/day), and the derived cost of energy expended by wheel running (5.024 kcal/kg/km). RESULTS A positive correlation between energy intake and expenditure was shown in rats, with greater energy expended due to growth and/or increased wheel running compensated by greater caloric intake (p < 0.001). An age-related (34 to 129 days) inverse relationship was noted between animal growth and relative energy intake (0.466 ± 0.01 to 0.258 ± 0.01 kcal/gm BW), expenditure (0.237 ± 0.00 to 0.200 ± 0.00 kcal/gm BW), and availability (0.229 ± 0.01 to 0.058 ± 0.00 kcal/gm BW), with a mean BW increase of 97% and a 75% decrease in available kcal/gm BW (p < 0.001). Regardless of growth-related decreasing trends in available energy or greater energy expended due to running distances, rats' continued with normal estrous cycling. CONCLUSION Results suggest that voluntary exercise does not adversely impact estrous cycling in the young ad lib-fed rat. In this study, greater energy expenditure was compensated with greater energy intake, allowing for greater energy availability to maintain the caloric cost of estrous cycling. Supported by Texas Food and Fiber Commission and Human Nutrition Research.

Predicting total energy expenditure from self-reported dietary records and physical characteristics in adult and elderly men and women

Energy requirements and nutrient intakes are commonly estimated from self-reported dietary records, but such estimation has proven to be unreliable. When energy intakes determined from dietary records are compared with energy expenditures measured with the use of doubly labeled water, the former consistently underestimate energy requirements and have a high degree of variability. The objective of this study was to reduce the bias and variability of self-reported dietary records through the use of stepwise multiple regression analysis to develop models that relate energy expenditure measured with the use of doubly labeled water to energy intake from dietary records, sex, and fat-free mass (or weight and height). Data from 54 healthy adult men and women were used to develop these models. Fat-free mass, energy intake, and sex accounted for 86% of the variability in energy expenditure, whereas energy intake, sex, height, and weight accounted for 83%. When the model relating fat-free mass, energy intake, and sex to energy expenditure was tested on published data, it reduced the bias and variability of self-reported dietary records from -17 +/- 27% to 3 +/- 16%. When the model relating energy intake, sex, weight, and height to energy expenditure was tested on published data, it reduced the bias and variability of self-reported dietary records from -19 +/- 25% to -0.3 +/- 19%. Results from this study indicate that a simple relation can be used to correct self-reported dietary records to estimated energy requirements.

Lactation, maternal behavior and infant growth in common marmoset monkeys ( Callithrix jacchus ): effects of maternal size and litter size

We examined the relationship between lactation performance and infant growth in a captive population of common marmosets (Callithrix jacchus) that varied in both maternal and litter size. Though common marmosets display a typical primate pattern of dilute milk and relatively slow infant growth rates (factors associated with low daily lactation investment and minimal maternal size effects), we hypothesized that the marmoset's small body size would make lactation investment more sensitive to maternal size than is true for larger-bodied primates. Smaller mothers rearing twins had lower milk fat, lower gross energy in milk samples collected in mid to late lactation and lower nursing-bout frequencies than did large mothers nursing twins. Lactation performance and maternal behavior did not differ between large and small mothers when rearing singletons, with a single exception: small mothers had a lower gross energy in mid-lactation milk samples. Relative growth rates in twins but not singletons were affected by maternal size, such that small mothers supported more growth per infant when rearing singletons while large mothers supported more growth per infant when rearing twins. Among the larger mothers, only, older mothers supported somewhat, though not significantly, less growth per infant, regardless of litter size. Twin infants of small mothers appeared to respond to below-optimal levels of milk yield by initiating maternal carrying less often. The relative energy intake of mothers was similar regardless of litter or maternal size. Small mothers rearing twins drew more heavily on reserves, reflected in a linear weight loss during lactation; however, the reserves drawn upon were inadequate to meet the lactation demand, resulting in lower milk energy output. In addition, small mothers rearing twins were more likely to be ill and less likely to be fertile in the year following lactation than were large mothers of twins or mothers of any size rearing singletons.

Energy and macronutrient intake in relation to dental caries incidence in urban black South African preschool children in 1991 and 1995: the Birth-to-Ten study.

To study energy and macronutrient intake in relation to dental caries incidence among urban black South African children at the ages of 1 and 5 years. Food frequency questionnaires and WHO caries diagnostic criteria were used. The study sample of 1639 urban black children with nutrition and dental information from the 1991 and/or 1995 Birth-to-Ten (BTT) Study interceptions comprised true longitudinal (n = 259) and cross-sectional (n = 1216 for 1991 and n = 164 for 1995) subjects. For the longitudinal group true dmfs (decayed, missing, filled surfaces) incidence and average intakes of energy and macronutrients between 1991 and 1995 were calculated. South Africa. Median macronutrient intakes were not significantly different between the cross-sectional and longitudinal samples. Dental caries prevalences at age 1 were 1.2% and 1.5% for the cross-sectional and longitudinal samples, respectively. By age 5 these values were 60.4% and 62.2%, respectively. The median dmfs score at age 1 was 0. At 5 years this was 2 for all children and 5 for those with caries. Statistical analysis for trend at age 5 showed a significant increase in caries prevalence with increasing energy, carbohydrate and added sugar in the cross-sectional sample only. The only significant changes in dmfs scores were seen for energy and added sugar for the whole sample. The r values between log(dmfs incidence + 0.3) and the average nutrient log variables were low, and a general linear models analysis showed no statistically significant effects on log(dmfs incidence + 0.3) of any of the log nutrient variables. For the relationship between macronutrient intake and caries (prevalence and incidence), a cross-sectional and true longitudinal study gave similar results.

Under- and overreporting of energy intake using urinary cations as biomarkers: relation to body mass index.

Under- and overreporting of energy intake in relation to body mass index (BMI, kg/m2) were examined by using 24-hour urinary sodium and potassium as biomarkers. The data were obtained from 2,124 men and 1,998 women aged 25-74 years who participated in the 1981-1984 Belgian Interuniversity Research on Nutrition and Health study conducted in Belgium. The ratios of dietary intake to urinary excretion of sodium and potassium, as a measure for relative underreporting, were inversely associated with BMI (for men, beta = -0.019 for sodium ratio and beta = -0.026 for potassium ratio; for women, beta = -0.017 for sodium ratio and beta = -0.019 for potassium ratio; all p < 0.0001) independent of age, smoking, alcohol intake, and educational level. Since 77% of dietary potassium was reported to be excreted in the urine, subjects for whom the (dietary potassium x 0.77)/urinary potassium ratio was <1 were considered underreporters and >1 as overreporters. The percentage of underreporters increased with increasing pooled sex-specific deciles of BMI (beta = 1.88, p < 0.0001) and was higher than the percentage of overreporters in 13 of 20 deciles. At a BMI of 25.4, the percentage of under- and overreporters equalized. In conclusion, the relative underreporting of energy intake and the percentage of underreporters increased with increasing BMI.