The relationship between dietary energy density and energy intake

Much of the research in ingestive behavior has focused on the macronutrient composition of foods; however, these studies are incomplete, or could be misleading, if they do not consider the energy density (ED) of the diet under investigation. Lowering the ED (kcal/g) by increasing the volume of preloads without changing macronutrient content can enhance satiety and reduce subsequent energy intake at a meal. Ad libitum intake or satiation has also been shown to be influenced by ED when the proportions of macronutrients are constant. Since people tend to eat a consistent weight of food, when the ED of the available foods is reduced, energy intake is reduced. The effects of ED have been seen in adults of different weight status, sex, and behavioral characteristics, as well as in 3- to 5-year-old children. The mechanisms underlying the response to variations in ED are not yet well understood and data from controlled studies lasting more than several days are limited. However, both population-based studies and long-term clinical trials indicate that the effects of dietary ED can be persistent. Several clinical trials have shown that reducing the ED of the diet by the addition of water-rich foods such as fruits and vegetables was associated with substantial weight loss even when patients were not told to restrict calories. Since lowering dietary energy density could provide effective strategies for the prevention and treatment of obesity, there is a need for more studies of mechanisms underlying the effect and ways to apply these findings.     

The effects of caloric dilution on meal patterns and food intake of ponies

In order to determine if horses will increase their intake in response to caloric dilution, four pony geldings were fed ad lib a mixed grain diet either undiluted (3.4 Mcal/kg of digestible energy) or diluted (wt/wt) with 25% sawdust (2.6 Mcal/kg) or with 50% sawdust (1.7 Mcal/kg). The mean daily caloric intake was 17,457 kcal (3.4 Mcal diet), 17,546 kcal (2.6 Mcal diet) and 12,844 kcal (1.7 Mcal). The mean time spent eating was 246 (3.4 Mcal), 351 (2.6 Mcal), and 408 (1.7 Mcal) minutes/day. Meal size increased and meal frequency decreased with increasing dilution. The median long survivorships of intermeal intervals were 6.4 min (3.4 Mcal), 3.95 min (2.6 Mcal) and 4.91 min (1.7 Mcal). Ponies responded to caloric dilution by increasing the volume of intake to maintain caloric intake when the diet had 25% diluent. When the diet was diluted by 50%, intake was increased, but not at a rate adequate to maintain caloric intake. However, the ponies were able to maintain body weight.     

Dietary restraint and obesity: Their effects on dietary intake

The current investigation evaluated the effects of levels of restraint, dietary intake, and obesity on both immediate (i.e., in the laboratory) and subsequent (i.e., outside the laboratory) self-reported dietary intake. Subjects were 102 college females, half of whom were given a high-caloric snack of a chocolate milkshake. Subjects were classified according to their level of chronic dieting status and relative weight. Chronic dieting status was measured by utilizing both the Concern for Dieting (CD) and the Weight Fluctuation (WF) factors of the revised restraint scale (Polivy, 1980). When using the WF factor, results indicated that obesity interacted with dieting status on total food consumption (i.e., calories for the entire day). That is, nondieting obese subjects reportedly ate significantly more calories than nondieting normal-weight subjects. Further, nondieting overweight subjects reported eating significantly more than low-restrained normal-weight subjects. On the CD factor, restrained eaters who received a preload reported eating significantly more calories than nondieters at lunch. For those subjects not receiving a milkshake, restrained eaters ate fewer calories at lunch than nondieters. The significance of these results for understanding possible energy imbalances in obese individuals as well as understanding pathological overeating and its consequences is discussed.This research was supported by funds from the National Heart, Lung, and Blood Institute (Grant HL36553) and a Centers of Excellence grant awarded to the Department of Psychology, Memphis State University, by the State of Tennessee. This research was conducted by the first author as part of her thesis requirement under the direction of the second author.     

Stomach filling may mediate the influence of dietary energy density on the food intake of free-living humans

The energy density of the diet has been demonstrated to be a significant influence on the daily intakes of humans which has led to the hypothesis that intake control is based upon the weight and volume of food and not its energy content. The study explored the roles of the components used in the calculation of energy density and stomach filling in dietary energy density effects upon intake. Dietary energy density relationships with intake and body size were studied in 264 male and 406 female free-living adult humans who provided a detailed record of their eating and drinking in 7-day diaries. High energy density was associated with larger amounts of food energy and larger amounts of solids, but lower total weight of meals, daily intakes, and weekly intakes. The lower total weight occurred due to lower fluid intake in drinks. Multiple regression analysis revealed that overall dietary energy density was more important than the energy density of particular nutrients. Intake of fluids in drinks did not contribute to the relationship of dietary energy density with intake. The estimated weight of the contents of the stomach following the meals was relatively constant regardless of the energy density of the meals, daily, or weekly intakes. Energy density was not significantly related with body size, height, weight, or BMI. The findings support the notion that short-term intake is controlled on the basis of its weight and volume as opposed to its food energy content.     

A twin study of the effects of energy density and palatability on energy intake of individual foods

The relative effects of energy density and palatability on energy intake, and whether there are familial influences on these effects, are not known. We investigated this issue in 7 pairs of healthy, male monozygotic twins (mean+/-SD age 26.3+/-8.6 years, BMI 23.7+/-3.2 kg/m(2)) in a clinical study involving covert ad libitum feeding of high-fat (HF, approximately 40%) and low-fat (LF, approximately 20%) diets in two 9-day phases. Diets were matched for average energy density, protein, fiber, and initial reported taste pleasantness, but these factors varied among the individual foods. Relationships between energy density, palatability, and energy intake were explored using regression and path analyses. Food energy density was positively associated with average taste pleasantness (r=0.46, P=0.03) independent of fat content, while energy intake from individual foods was positively associated with both energy density (r=0.56, P=0.007) and taste pleasantness (r=0.73, P<0.0001). In path analysis, both energy density and taste pleasantness directly influenced energy intake, and energy density also indirectly influenced energy intake by influencing taste pleasantness. In addition, there were significant within-twin pair similarities for the energy density-taste pleasantness and energy density-energy intake relationships (P<0.03) with the result that some twin pairs but not others identified foods high in energy density as more pleasant tasting and consumed relatively more energy from them compared to foods low in energy density. These results suggest that there are familial influences on the extent to which high energy density foods are preferred and contribute to total energy intake.     

Acute effects of knowledge-based work on feeding behavior and energy intake

The aim of this study was to evaluate the impact of knowledge-based work (KBW) on feeding behavior and spontaneous energy intake with the use of a repeated measures/within-subjects design. We used a two-session protocol including an ad libitum buffet preceded by either rest in a sitting position for 45 min or a cognitive task (reading a document and writing a summary of 350 words using a computer) over the same time period. In this regard, 15 healthy Laval University female students (mean age = 24.1+/-2.2 years, mean BMI = 24.0+/-4.3 kg/m2) were recruited to participate in this study. Anthropometric variables, energy expenditure, heart rate, blood pressure, food intake (dietary record), and appetite sensation markers were measured at each testing session, and two questionnaires [Three-Factor Eating Questionnaire (TFEQ) and State-Trait Anxiety Inventory (STAI)] were administered. In addition, a buffet-type meal was used to measure spontaneous energy intake and macronutrient preferences. We found that the mean energy expenditure of the two conditions was about comparable (difference of 13 kJ between the two tasks) whereas the mean ad libitum energy intake after the KBW task exceeded that measured after rest by 959 kJ (p < 0.01). Although a higher absolute energy intake was observed for the three macronutrients after the KBW task (p < 0.05), no specific preference was detected, as reflected by the comparable percent of energy from each macronutrient in the two conditions. No significant difference in appetite sensation markers was observed between the two conditions, although the subjects ate more in the buffet-type meal after the KBW task. Furthermore, the subjects did not compensate by decreasing food intake for the rest of the day, suggesting a net caloric surplus. We also observed negative correlations between cognitive dietary restraint (TFEQ) and spontaneous energy intake in both conditions. In conclusion, our results demonstrate that mental work solicited by KBW has the potential to induce a higher spontaneous energy intake. This also raises the possibility that KBW adds a new component to sedentariness that might further accentuate the positive energy balance that is more likely to occur when one is inactive.     

Beneficial effects of high dietary fiber intake in patients with type 2 diabetes mellitus

BACKGROUND: The effect of increasing the intake of dietary fiber on glycemic control in patients with type 2 diabetes mellitus is controversial. METHODS: In a randomized, crossover study, we assigned 13 patients with type 2 diabetes mellitus to follow two diets, each for six weeks: a diet containing moderate amounts of fiber (total, 24 g; 8 g of soluble fiber and 16 g of insoluble fiber), as recommended by the American Diabetes Association (ADA), and a high-fiber diet (total, 50 g; 25 g of soluble fiber and 25 g of insoluble fiber), containing foods not fortified with fiber (unfortified foods). Both diets, prepared in a research kitchen, had the same macronutrient and energy content. We compared the effects of the two diets on glycemic control and plasma lipid concentrations. RESULTS: Compliance with the diets was excellent. During the sixth week, the high-fiber diet, as compared with the the sixth week of the ADA diet, mean daily preprandial plasma glucose concentrations were 13 mg per deciliter [0.7 mmol per liter] lower (95 percent confidence interval, 1 to 24 mg per deciliter [0.1 to 1.3 mmol per liter]; P=0.04) and mean median difference, daily urinary glucose excretion 1.3 g (0.23; 95 percent confidence interval, 0.03 to 1.83 g; P= 0.008). The high-fiber diet also lowered the area under the curve for 24-hour plasma glucose and insulin concentrations, which were measured every two hours, by 10 percent (P=0.02) and 12 percent (P=0.05), respectively. The high-fiber diet reduced plasma total cholesterol concentrations by 6.7 percent (P=0.02), triglyceride concentrations by 10.2 percent (P=0.02), and very-low-density lipoprotein cholesterol concentrations by 12.5 percent (P=0.01). CONCLUSIONS: A high intake of dietary fiber, particularly of the soluble type, above the level recommended by the ADA, improves glycemic control, decreases hyperinsulinemia, and lowers plasma lipid concentrations in patients with type 2 diabetes.     

Effects of energy density of daily food intake on long-term energy intake

An important question that has been raised recently is whether it is mainly the energy density (ED) of the food consumed or its macronutrient composition that determines daily energy intake (EI). In this scope, the effect of ED on EI has been assessed in short-term as well as long-term experiments. Over the short term, i.e., during a meal, it was found that ED affects EI directly; then subjects mainly monitor the weight of the food ingested. Over the long term, the effects of ED on EI are modulated. Average daily energy intake (ADEI) does not only consist of meals but also includes snacks and drinks. ADEI appears to be related to ED of the food and drinks where ED is at least determined by specific macronutrients (primarily fat and carbohydrate), but not when ED is determined only by the weight of water. With respect to the separate effects of the ED of foods and of drinks on ADEI, only ED from foods had a significant relationship with total EI. Moreover, during daily food intake, subjects seem to adapt their portion sizes to estimated EDs. Long-term studies have shown that dietary restraint compensates for the effect of increases in ED on ADEI, whereas unrestrained eaters compensate for the effect of decreases in ED on ADEI. In conclusion, ED determines short-term EI. This cannot be extrapolated to the long term because only the ED of food, and not the ED of drinks, determines total EI. In addition, over the long term, the short-term effect is modulated by dietary restraint and adapted portion sizes. ED is not a universal concept that determines EI, yet rather a characteristic of the macronutrients: mainly fat and carbohydrate contributing to variation in EI.     

The relationship between dietary intake, exercise, energy balance and the space craft environment

Space flight is associated with the loss of skeletal muscle, principally from muscles with anti-gravity functions. Examination of data across different missions can permit a distinction to be made between true microgravity responses and what are mission-specific responses. Protein metabolism has been investigated on six missions, four short-term [Shuttle missions Space Life Sciences 1 (1991, SLSI), Space Life Sciences 2 (1993, SLS2), Deutsche-2 (1993, D2) and the Life and Microgravity Sciences (1996, LMS)] and two long-term missions (Skylab 1993 and NASA/MIR, 1996-1998). Measurements made include dietary intake (six missions), nitrogen balance (four missions), whole-body protein kinetics with [15N]glycine as the tracer (four missions) and cortisol excretion (three missions). Also available for comparison are bed rest studies with and without exercise. The purpose of this paper is to see what can be learnt about the muscle loss problem by comparing metabolic results across the six missions for which data are available and against bed rest. The analysis suggests that there is a linkage between the inability to maintain energy balance and exercise, and the connection is the decreased efficiency of removal of the metabolic by-products of exercise (heat, CO2) during space flight.     

The effects of alterations in dietary carbohydrate intake on the performance of high-intensity exercise in trained individuals

This study was designed to examine the effects of alterations in dietary carbohydrate (CHO) intake on the performance of high-intensity exercise lasting approximately 10 min (EXP 1) and 30 min (EXP 2). Trained subjects exercised to exhaustion on four occasions on a cycle ergometer at 90% of maximal oxygen consumption (V˙O_2max; EXP 1, n?=?5) and 80% of V˙O_2max (EXP 2, n?=?7). The first two tests were familiarisation trials and were carried out following the subjects' normal diet. Normal training was continued but standardised during the periods of dietary control. The subsequent two tests were performed 2 weeks apart after 7 days of dietary manipulation. The two diets were a 70% and a 40% CHO diet, isoenergetic with each subject's normal diet and administered in a randomised order. At both exercise intensities, time to exhaustion following the high CHO and low CHO diets was not different [mean (SD) EXP 1: 11.56 (3.78) min and 8.95 (2.35) min, P?=?0.22; EXP 2: 26.9 (7.4) min and 26.5 (6.5) min, P?=?0.90]. No differences in resting blood metabolite concentrations were found apart from a lower β-hydroxybutyrate (β-HB) level following the high CHO diet in EXP 2. Blood lactate was higher after exercise at 90% of V˙O_2max following the high CHO diet. Blood lactate was higher, and β-HB lower during exercise at 80% of V˙O_2max following the high CHO diet. No differences were found in the other blood metabolites tested. The respiratory exchange ratio after 15 min of exercise at 80% of V˙O_2max was higher on the high CHO diet. No differences in oxygen uptake, heart rate (EXP 2) or ratings of perceived exertion (both experiments) were found between conditions. These results indicate that moderate changes in diet composition during training do not affect the performance of high-intensity exercise in trained individuals when the total energy intake is moderately high.     

Effects of dietary fat on appetite and energy intake in health and obesity--oral and gastrointestinal sensory contributions

While epidemiological studies have revealed a strong positive relationship between the intake of dietary fat with total energy intake and body weight, laboratory-based studies investigating physiological effects of fat have demonstrated that the direct exposure of receptors in the oral cavity and small intestine to fat, specifically fatty acids (FAs), induces potent effects on gastrointestinal (GI) motility and gut peptide secretion that favor the suppression of appetite and energy intake. Recent studies in humans have demonstrated an association between a decreased ability to detect the presence of FAs in the oral cavity with increased energy intake and body mass index suggesting that impairment of oral fat sensing mechanisms may contribute to overeating and obesity. Furthermore, while sensing of the presence of FAs in the small intestine results in the modulation of GI motility, stimulation of GI hormone release, including cholecystokinin (CCK) and peptide YY (PYY), and suppression of subsequent energy intake, recent data indicate that these effects of fat are attenuated in individuals with reduced oral sensitivity to fat, and following consumption of a high-fat diet. This review will focus on emerging knowledge about the physiological mechanisms that sense the presence of fat in both the oral cavity and the small intestine, and environmental factors, such as high-fat diet exposure and energy restriction, that may modulate sensitivity to nutrients, and thereby contribute to the regulation of appetite and body weight.     

Self-management of dietary intake using mindful eating to improve dietary intake for individuals with early stage chronic kidney disease

Using mindful eating to improve specific dietary recommendations has not been adequately studied. This feasibility study examined an intervention, self-management of dietary intake using mindful eating, with 19 participants that had mild to moderate chronic kidney disease, using a prospective, single group, pretest–posttest design. The intervention had six weekly classes focused on self-management using mindful eating, goal-setting, problem-solving, and food label reading. Weight, body mass index (BMI), 3-day 24-h dietary recalls and fasting blood samples were measured. Participants improved significantly in mean weight (203.21 ± 42.98 vs 199.91 ± 40.36 lbs; P = 0.03) and BMI (32.02 ± 5.22 vs 31.57 ± 5.27 kg/m²; P = 0.04), but not in dietary intake nor blood measures with the exception of cis-beta-carotene levels (0.020 + 0.012 vs 0.026 + 0.012 mcg/mL; P = 0.008), which correlates to fruit and vegetable servings. These promising results warrant further testing of the intervention in randomized control trials.     

Sleep symptoms associated with intake of specific dietary nutrients

Sleep symptoms are associated with weight gain and cardiometabolic disease. The potential role of diet has been largely unexplored. Data from the 2007–2008 National Health and Nutrition Examination Survey (NHANES) were used (n = 4552) to determine which nutrients were associated with sleep symptoms in a nationally representative sample. Survey items assessed difficulty falling asleep, sleep maintenance difficulties, non‐restorative sleep and daytime sleepiness. Analyses were adjusted for energy intake, other dietary factors, exercise, body mass index (BMI) and sociodemographics. Population‐weighted, logistic regression, with backwards‐stepwise selection, examined which nutrients were associated with sleep symptoms. Odds ratios (ORs) reflect the difference in odds of sleep symptoms associated with a doubling in nutrient. Nutrients that were associated independently with difficulty falling asleep included (in order): alpha‐carotene (OR = 0.96), selenium (OR = 0.80), dodecanoic acid (OR = 0.91), calcium (OR = 0.83) and hexadecanoic acid (OR = 1.10). Nutrients that were associated independently with sleep maintenance difficulties included: salt (OR = 1.19), butanoic acid (0.81), carbohydrate (OR = 0.71), dodecanoic acid (OR = 0.90), vitamin D (OR = 0.84), lycopene (OR = 0.98), hexanoic acid (OR = 1.25) and moisture (OR = 1.27). Nutrients that were associated independently with non‐restorative sleep included butanoic acid (OR = 1.09), calcium (OR = 0.81), vitamin C (OR = 0.92), water (OR = 0.98), moisture (OR = 1.41) and cholesterol (OR = 1.10). Nutrients that were associated independently with sleepiness included: moisture (OR = 1.20), theobromine (OR = 1.04), potassium (OR = 0.70) and water (OR = 0.97). These results suggest novel associations between sleep symptoms and diet/metabolism, potentially explaining associations between sleep and cardiometabolic diseases.     

Dissociation of the effects of preload volume and energy content on subjective appetite and food intake

Previous research suggests that enhancing the volume of a food preload without altering energy content can result in reduced appetite, although the limited evidence means that the conditions under which this effect will occur are not yet clear. In the present study, we used a Universal Eating Monitor (UEM) to record test meal intake constantly, in parallel with appetite ratings, following soup-based preloads that varied both in volume (150 vs. 450 ml) and energy density (1.4 vs. 4.2 kJ/ml). Healthy young men (n=20) received four different preload conditions (repeated measures) followed by unlimited hot pasta test meals (interval 30 min). They completed appetite ratings during and after each laboratory session, and food diaries for the afternoon and evening following each session. Subjective appetite after the preloads was reduced by the high-volume preloads relative to low-volume preloads, with no difference between the two at each volume level. This indicates an effect of volume, but no effect of energy. Test meal intake in the high-volume, high-energy-density condition was reduced relative to the other conditions, which did not differ from one another. This indicates an effect of total energy, but no effect of volume. The dissociation between these different measures of appetite might be explained in terms of largely cognitive influences on subjective appetite between preload and test meal, contrasted with stronger physiological influences on actual intake during the test meal. With regard to previous studies, it is argued that food volume is more influential under circumstances where gastric volume is closer to its normal limits.     

Effects of dietary intake of garlic on intestinal trematodes

The current strategy for the control of helminth infections relies on chemotherapy. However, resistance appearance is promoting the necessity of developing new drugs against trematodes. Herein, potential trematocidal effects of garlic (Allium sativum) are investigated in the context of intestinal foodborne trematodes, employing the Echinostoma caproni-mouse model. Daily administration of dietary doses of garlic was conducted in three groups of mice: (i) before infection (prophylaxis), (ii) after infection (therapeutic) and (iii) both, before and after infection (continuous). A fourth group of mice, not exposed to garlic, was used as control. No differences in worm recovery, fecundity and local cytokine expression profiles were found with respect to control infections. However, considerable alterations in tegument structure, including swelling, furrowing, vacuolization and changes in secretory bodies were detected in garlic-exposed parasites using scanning and transmission electron microscopy. Protein secretion was markedly reduced in response to garlic, whereas up-regulation of several proteins, such as major vault protein and tER-ATPase, was observed in treated worms. The results presented herein provide new insights in the anthelminthic activity of bioactive garlic compounds and the manner that parasites respond to toxins.

     

Energy density and portion size: their independent and combined effects on energy intake

The energy density (kcal/g) and the portion size (g) of foods have been identified as two properties of foods that can modulate energy intake. Recent studies have shown that when either the energy density or the portion size of foods is increased, energy intake increases. Within a meal, when both factors are increased simultaneously, their effects are independent and add together to increase energy intake. On the other hand, reducing the energy density of a first course, while increasing the volume that is consumed, leads to a decrease in energy intake at the entire meal. The mechanisms by which both factors exert their influence are not well understood but likely include cognitive and orosensory factors as well as physiological controls related to gastric distention and gastric emptying. Findings from studies in this area of research provide evidence that the energy density and the portion size of foods are important determinants of energy intake. An environment in which the food supply is ample and large portions of energy-dense foods are readily available to consumers can contribute to an overconsumption of calories.     

Quantitative estimation of dietary intake in patients on hemodialysis

A simple method to calculate the amount of dietary (protein, sodium and potassium) intake in hemodialyzed patients was developed. In 8 nutritionally stable patients, the amount of dietary intake was monitored conventionally by a dietary record method. In contrast, assuming that the amount of dietary intake was equal to the amount of accumulation in the body, the former was calculated as the change in the product of serum concentrations and total body fluid volume, which was estimated based on the sex and body build of each patient. The urea accumulation was converted to the protein intake. The interdialytic dietary protein and sodium intake calculated by this method, 120 +/- 10 g and 240 +/- 40 mEq, respectively, was not significantly different from that obtained by the dietary record, while the interdialytic potassium accumulation, 60 +/- 7 mEq, was significantly smaller than the dietary intake, 110 +/- 9 mEq, obtained by the record method, though the correlation was significant. Thus, the amount of protein and sodium intake can be calculated simply without diet research or body fluid volume measurements. Although potassium intake can not be calculated exactly because of intestinal loss, this simple method gives us a rough estimate. In addition, multiple regression analysis showed that the amount of energy intake obtained by the record method may be explained by the protein and sodium intake estimated by simple calculation.     

Effect of increased dietary salinity on the reproductive status and energy intake of xeric and mesic populations of the spiny mouse, Acomys

The possible role of increased dietary salinity as a proximate regulator of reproduction in xeric population of golden spiny mice (Acomys russatus) and mesic population of common spiny mice (A. cahirinus) was tested. In the wild, as the dry season progresses, evaporative water loss in the vegetation increases. This leads to increase in particle concentration of plant tissues. Thus, species consuming a plant diet are exposed to increased dietary salinity. Both male and female individuals of A. russatus were subjected to gradually increasing dietary salinity (0.9%, 2.5%, 3.5%, and 5%) while those of A. cahirinus only up to 3.5% for a total period of 8 and 6 weeks, respectively. Urine osmolarity showed a significant increase under 3.5% and 5% salinity in A. russatus and 2.5% and 3.5% in A. cahirinus. Testis mass and spermatogenesis were significantly reduced while uterine mass and vaginal estrus cycles were not affected in A. russatus. None of the parameters was significantly affected in A. cahirinus. Increase in salinity also significantly reduced body mass in A. russatus but not in A. cahirinus. Mass-specific daily digestible energy intake was not significantly affected by increased salinity in both species. Recovery individuals regained body mass quickly and surpassed initial values after four weeks. However, testis mass and spermatogenesis did not show recovery. The results suggest that increase in dietary salinity could be used as a proximate signal to regulate reproduction in A. russatus by halting it in males, as the dry season progresses while such role in the mesic population of A. cahirinus is unlikely.     

Effect of the preceding day's energy intake on the total energy cost of light exercise

The effect of a variation in the preceding day's dietary energy intake-4, 10 and 18 MJ-on the oxygen consumption and respiratory quotient at rest and at work before and after a test meal (4 MJ) was investigated. 7 normal male subjects were studied at 3 different experimental situations. During the first day the subjects had an energy intake of 10 MJ and normal activity. The following morning measurements of V(O2) and V(CO2) were performed at rest and at work on a bicycle ergometer (36 W) before and after the test meal. The same measurements were performed on the following day but the dietary intake between the two sets of measurement was then either 6, 0 or 14 MJ. No significant effect was found of the preceding day's dietary energy intake on the oxygen consumption or on the energy transformed during rest, during exercise before and after the test meal. The results do not support the conclusions of previously published studies, proposing a significant feed-back mechanism tending to control the body energy content by regulation of the energy expenditure through chemical or mechanical uncoupling.