Effect of dietary energy density on total ad-libitum energy consumption by recovering malnourished children.

Clinical trials were conducted to measure the effect of dietary energy on total daily energy intakes by nine hospitalized young children recovering from protein-energy malnutrition. Semi-solid mixed diets containing either 50 or 100 kcal/100 g were offered at fixed intervals five times per day until the children refused further intake. Each diet was offered for seven consecutive days in alternate order. The mean +/- SD amount consumed with the low-density (LD) diet was significantly greater than with the high-density (HD) diet (220 +/- 35 vs 148 +/- 21 g/kg/d, P less than 0.001), but the amount of energy consumed with the HD diet was significantly greater than with the LD diet (148 +/- 21 vs 110 +/- 18 kcal/kg/d, P less than 0.001). There were no differences in total daily intake by day of diet period with the HD diet, but the intakes increased during the first 2-4 days with the LD diet. The maximum intakes at a single meal averaged between 40 and 66 g/kg/d for individual children receiving the LD diet, and were negatively related to the children's lengths and weight-for-length Z scores. We conclude that dietary energy density limited the amount of energy consumed from LD weaning diets offered at fixed frequencies, presumably because the volume of intake required to satisfy the children's energy needs exceeded their gastric capacity.     

Effects of energy density and feeding frequency of complementary foods on total daily energy intakes and consumption of breast milk by healthy breastfed Bangladeshi children

BACKGROUND: Information is needed on the minimum energy density and feeding frequency of complementary foods that can provide adequate energy intakes (EIs) for healthy breastfed children. OBJECTIVES: The objectives of the study were to evaluate the effects of various energy densities and feeding frequencies of complementary foods on EI from these foods, breast milk consumption, and total EI from both sources. DESIGN: During 9 separate, randomly ordered dietary periods lasting 3-6 d each, we measured intakes of food and breast milk by 18 healthy breastfed children 8-11 mo of age who, 3, 4, or 5 times/d, were fed porridge with a coded energy density of 0.5, 1.0, or 1.5 kcal/g. Food intake was measured by weighing the feeding bowl before and after meals, and breast milk intake was measured by test weighing. RESULTS: The mean amounts of complementary foods consumed were inversely related to their energy density and positively related to the number of meals/d (P < 0.001 for both); EIs from foods were positively related to both factors. Breast milk intake decreased slightly but progressively, with greater energy density and feeding frequency of complementary foods; total EIs (kcal/d) increased in relation to both factors (P < 0.001 for both). CONCLUSIONS: The energy density and feeding frequency of complementary foods affect infants' total daily EI and breast milk consumption. Recommendations can be developed for the appropriate combinations of these dietary factors that are compatible with adequate EI, although longer-term effects of complementary feeding practices on breast milk intake and breastfeeding duration need further community-based studies.     

Energy cost of lactation, and energy balances of well-nourished Dutch lactating women: reappraisal of the extra energy requirements of lactation

At 9 wk postpartum the difference in energy intake of 40 lactating (2440 +/- 430 kcal/d) and 16 nonlactating women (1680 +/- 400 kcal/d) was 760 kcal/d but decreased to 550 kcal/d when adjusted for habitual intakes and body weight. Energy cost of lactation amounted to 650 kcal/d (breast-milk production, 745 +/- 130 g/d). When compared with nonlactating counterparts, the lactating women mainly achieved energy balance by eating more. Sixteen of the 40 lactating women were also studied at 56 wk. Their cost of lactation at 5-13 wk was 630 kcal/d (breast-milk production, 720 +/- 124 g/d); these women met their energy cost of lactation by eating more (415 kcal/d); by tissue mobilization (35 kcal/d), and by reducing energy expenditure (180 kcal/d). The present study helps in the understanding of how well-nourished women with an adequate lactational performance may cope in everyday life with the energy stress of lactation, and suggests that current recommendations of energy needs during lactation are too high.     

Effects of common illnesses on infants' energy intakes from breast milk and other foods during longitudinal community-based studies in Huascar (Lima), Peru

To assess the effects of common infections on dietary intake, 131 Peruvian infants were observed longitudinally. Home surveillance for illness symptoms was completed thrice weekly, and food and breast-milk consumption was measured during 1615 full-day observations. Mean (+/- SD) energy intakes on symptom-free days were 557 +/- 128 kcal/d (92.4 +/- 26.5 kcal.kg-1.d-1) for infants aged less than 181 d and 638 +/- 193 kcal/d (77.7 +/- 25.7 kcal.kg-1.d-1) for infants aged greater than 180 d. Statistical models controlling for infant age, season of the year, and individual showed significant 5-6% decreases in total energy intake during diarrhea or fever. There were no changes with illness in the frequency of breast-feeding, total suckling time, or amount of breast-milk energy consumed. By contrast, energy intake from non-breast-milk sources decreased by 20-30% during diarrhea and fever, and the small decrements in total energy consumption during illness were explained entirely by reduced consumption of non-breast-milk foods.     

Effect of low- and high-calcium dairy-based diets on macronutrient oxidation in humans

OBJECTIVE: Higher calcium and dairy intakes may be associated with lower body weights, but a mechanism in humans has yet to be elucidated. We compared the effects of a dairy-based high-calcium diet and a low-calcium diet on macronutrient oxidation. RESEARCH METHODS AND PROCEDURES: Subjects (10 men and nine women) consumed a low-dairy (LD, approximately one serving per day, approximately 500 mg Ca(2+)/d) or high-dairy (HD, approximately three to four servings per day, approximately 1400 mg Ca(2+)/d) energy balance diet for 1 week. Each diet condition was performed twice. On the 7th day, subjects were studied in a room calorimeter under one of four study conditions, applied in a randomized crossover design. Within each diet condition, subjects were studied under conditions of energy balance and acute energy deficit. The deficit (-600 kcal/d) was induced only for the 24 hours that subjects resided in the room and was achieved by a combination of caloric restriction and exercise. RESULTS: Under energy balance conditions, there was no effect of diet treatment on respiratory quotient or 24-hour macronutrient oxidation. Under energy deficit conditions, 24-hour fat oxidation was significantly increased on the HD diet (HD with deficit = 136 +/- 13 g/d, LD with deficit = 106 +/- 7 g/d, p = 0.02). DISCUSSION: Consumption of a dairy-based high-calcium diet increased 24-hour fat oxidation under conditions of acute energy deficit. We hypothesize that these effects are due to an increased fat oxidation during exercise.     

Effects of dietary viscosity and energy density on total daily energy consumption by young Peruvian children.

BACKGROUND: Results of prior studies of the effect of viscosity reduction of high-energy-density, starch-containing diets on young children's energy intakes are inconsistent, possibly because of differences in the characteristics of the unmodified diets with which the low-viscosity diets were compared. OBJECTIVE: Our objective was to determine the effects of dietary viscosity and energy density on total daily energy consumption by young, non-breast-fed children. DESIGN: We measured the amount of food consumed and the duration of meals during 3 substudies, in each of which 3 study diets were offered for 4 consecutive days each in random sequence: high energy density, high viscosity (HD-HV); high energy density, low viscosity (HD-LV); and low energy density, low viscosity (LD-LV). The viscosity and energy density of the unmodified starch-containing HD-HV diet were varied across substudies to determine whether the effect of amylase liquefaction was related to the initial characteristics of the HD-HV diet. The viscosity of the HV diets ranged from 79000 to 568000 mPa s; energy density of the HD diets ranged from approximately 4.18 to 4.93 kJ (1.00-1.18 kcal)/g. Viscosity of the LV diets was approximately 3000 mPa s and the energy density of the LD diets was approximately 2.47 kJ (0.6 kcal)/g. RESULTS: In each substudy, children consumed more of the LD-LV diet (g kg body wt(-)(1) d(-)(1)) than of the other diets and more of the HD-LV diet than of the HD-HV diet (P < 0.001). Energy consumption from the HD-LV diet was greater than from the other diets (P < 0.001), but the energy intakes from the latter diets were not significantly different. CONCLUSION: Amylase liquefaction of HD-HV porridges resulted in increased energy consumption by young children.     

Protein requirements of infants: a reexamination of concepts and approaches

Estimates of protein requirements of infants aged 3-4 mo by FAO/WHO/UNU (1.47 +/- 0.26 g.kg-1.d-1 as crude protein, N X 6.25) are judged to be overestimates. From simulation analyses we suggest that 1.1 +/- 0.1 - 0.2 g.kg-1.d-1 is a more reasonable estimate. This is consistent with statements that 1) breast milk that provides an average of 16 g protein/1000 kcal or a fixed-composition formula that contains 17 g protein/1000 kcal is adequate for essentially all such infants and 2) average protein intakes from that milk or formula would be approximately 1.65 or 1.75 g.kg-1.d-1, close to current average requirements estimates. It appears that there has been a difference in the concepts of requirement usually applied to infants and to adults and a systematic misinterpretation of breast-milk data in estimating requirements. A plea is issued for the application of epidemiologic approaches as a part of requirement estimation.     

Smoking during pregnancy and lactation and its effects on breast-milk volume

The influence of cigarette smoking on daily breast-milk volume was measured by the dose-to-mother deuterium-dilution method in 10 smoking and 10 nonsmoking mothers. After administration of deuterium to the mother, breast milk and infant saliva were sampled over 14 d and analyzed by mass spectrometry. Nonsmoking mothers had a significantly greater breast-milk volume than did smokers [961 +/- 120 vs 693 +/- 110 g/d, mean +/- SD; t = 5.21, P less than 0.0001). Growth rates of the infants were also measured. Weight increase of infants of non-smoking mothers was 550 +/- 130 g whereas of infants of smoking mothers it was only 340 +/- 170 g (t = 3.11, P less than 0.01). These results indicate that cigarette smoking has a negative influence on breast-milk volume whereas the lower infant-growth rates of the smoking mothers suggest also that their breast-milk output was insufficient to support the energy requirements of their infants.     

Energy metabolism, body composition, and milk production in healthy Swedish women during lactation

Variables of relevance to energy requirements during reproduction were studied in 23 healthy lactating Swedish women. Body composition and resting metabolic rate (RMR) were studied before pregnancy and three times postpartum. Energy intake was studied before pregnancy and, together with breast-milk production, 2 mo postpartum. The women gained 5.8 +/- 4.2 kg fat during pregnancy and their average fat content was unchanged during the first 2 mo of lactation whereas a slight loss (1.7 +/- 4.2 kg) occurred during the following 4 mo. RMR increased slightly during lactation in spite of a decrease in fat-free body weight 2 and 6 mo postpartum. Energy intake increased during lactation (280 +/- 440 kcal/d). The women produced 740 +/- 150 g breast milk/d containing 0.64 +/- 0.08 kcal/g. The results indicate that current estimates of energy needs during lactation may be too high.     

The contribution of breast milk to toddler diets in western Kenya

OBJECTIVE: To understand the relative contributions of breast milk and the weaning diet to overall nutrient intake, with a view to designing and implementing appropriate programmes to improve complementary feeding in developing countries. METHODS: Complementary food intake was measured in a sample of 250 toddlers (mean baseline age: 13.9 +/- 2.4 months) using 24-h dietary recall interviews administered once every 3 weeks over a 6-month period. Breast-milk intake over a 24-h period was measured using the test-weighing method in a subsample of 50 children. Regression effects of age and sex on observed milk intakes were estimated and imputed to the whole sample to estimate mean intake over the observation period. Total energy and nutrient intakes were evaluated for adequacy with reference to published estimates of toddler requirements. FINDINGS: Total energy intake (1029 kcal/day) was adequate, with breast milk supplying an average of 328 kcal/day (32%), but vitamin A, riboflavin, calcium, iron and zinc intakes were below current estimates of required intakes. Observed limitations in nutrient intake were consistent with the finding that almost half of the toddlers were stunted. The prevalence of wasting was 6% at baseline and 4% at final assessment. Although food consumption increased when breastfeeding stopped, it could not fully compensate for the fat and vitamin A previously supplied by breast milk. CONCLUSIONS: The nutritional role of mother's milk in the second year is inversely related to the adequacy of the complementary diet. In this study, breast milk was an irreplaceable source of fat and vitamin A. When the weaning diet is inadequate for key nutrients because of low intake or poor bioavailability, breast milk assumes greater nutritional significance in the second year of life but does not guarantee adequate nutrient intakes.     

Sources of variance in milk and caloric intakes in breast-fed infants: implications for lactation study design and interpretation

Between-individual variation (BIV) and day-to-day variation (DDV) of total caloric and human milk intakes were examined in 17 infants. Nine were studied at months 5 and 6; 8 at months 6 and 7. All 17 were exclusively breast-fed for 5 full mo after which solid foods were added to the diet. Each infant was studied for five consecutive 24-h periods during which serial measurements were made of milk intake (test weighing) and solid food intake (pre- and postfeeding jar weighing). Total daily caloric intakes (kcal/day) were (mean +/- SD) 492 +/- 57, 547 +/- 70, and 567 +/- 98 at months 5, 6, and 7, respectively. Estimates of caloric intakes (kcal/kg/day) adjusted for body weight were 65.9 +/- 6.7, 72.6 +/- 11.2, and 70.9 +/- 13.0 at months 5, 6, and 7, respectively. Milk intakes (g/day) were 735 +/- 85, 640 +/- 106, and 562 +/- 214 at months 5, 6, and 7, respectively. BIV of milk intake increased after the introduction of solid foods. DDV (expressed as coefficient of variation) of caloric intake was nearly constant at each monthly observation and BIV increased from 8.8 at month 5 to 14.6 at month 7. The numbers of 24-h periods and subjects required for estimates of known precision of caloric and milk intakes of older breast-fed infants can be determined from these estimates of variance.     

Human milk intake and growth faltering of rural Mesoamerindian infants.

To determine whether growth faltering during early infancy was attributable to inadequate intake of human milk, the nutrient intakes and growth of 30 Otomi infants from Capulhuac, Mexico, were studied at 4 or 6 mo of age. Growth was monitored monthly from 1 through 6 mo of age. The 2H dose-to-the-mother method was used to measure human milk intake. Energy, protein, lactose, and fat concentrations in milk were analyzed by standard techniques. Mean (+/- SD) human milk intakes were 885 +/- 145 and 869 +/- 150 g/d at 4 and 6 mo, respectively. Protein and lactose concentrations in milk were normal but fat and consequently energy concentrations were abnormally low. Energy intakes averaged 81 +/- 14 kcal.kg-1.d-1 at 4 mo and 72 +/- 14 kcal.kg-1.d-1 at 6 mo. Growth faltering by 6 mo was evidenced by the significant decline in growth velocities and National Center for Health Statistics Z scores. Weight gain at 6 mo was 8.1 +/- 3.5 g/d and length gain was 1.0 +/- 0.34 cm/mo. Weight-for-age and length-for-age Z scores were -0.81 +/- 0.94 and -1.51 +/- 0.83, respectively. Growth velocities were not significantly correlated with nutrient intakes. Growth faltering among the Otomi infants despite energy intakes comparable to those of breast-fed infants in more protected environments may have resulted from an increase in the need for nutrients or from a growth-limiting nutrient, other than energy, in their diet.     

Fortified complementary foods with or without alpha-amylase treatment increase hemoglobin but do not reduce breast milk intake of 9-mo-old Zambian infants

BACKGROUND: Malnutrition in late infancy in developing countries may result from poor-quality complementary foods that displace breast milk. OBJECTIVE: The objective of the study was to assess the effects of fortified complementary blends of different energy densities on growth, hemoglobin concentrations, and breast milk intake of 9-mo-old Zambian infants. DESIGN: Infants were randomly assigned at 6 mo of age to receive for 3 mo a fortified blend of maize, beans, bambaranuts, and groundnuts [Chilenje Baby Mix (CBM); energy density: 68 kcal/100 g; n = 37] or a similar blend with alpha-amylase (CBMA; energy density: 106 kcal/100 g; n = 44). Cross-sectional data were obtained at 9 mo for a control group of infants (n = 69) not given the diets. Breast milk intake was measured by using the dose-to-the-mother deuterium dilution technique. RESULTS: No differences in weight or length z scores, all of which were within normal ranges, were seen between groups at 9 mo. Percentage fat mass was significantly (P = 0.01) greater in the infants in both the CBM (23.2 +/- 2.7%) and CBMA (23.4 +/- 2.5%) groups than in the control group (21.6 +/- 2.6%). Hemoglobin concentrations were significantly (P = 0.03) greater in both intervention groups (CBM group: 104 +/- 12 g/L: CBMA group: 103 +/- 12 g/L) than in the control group (98 +/- 14 g/L). Breast milk intake was not significantly (P = 0.87) different between groups (CBM group: 614 +/- 271 g/d; CBMA group: 635 +/- 193 g/d; control group: 653 +/- 221 g/d). CONCLUSIONS: The study foods improved hemoglobin concentrations without reducing breast milk intake and may be used to improve the nutritional status of infants in developing countries.     

Disagreement of energy and macronutrient intakes estimated from a food frequency questionnaire and 3-day diet record in girls 4 to 9 years of age

BACKGROUND: The Block98 food frequency questionnaire (FFQ) has been validated for dietary assessment of usual intakes in adults, but not in children. OBJECTIVE: To assess the agreement of the Block98 FFQ and 3-day diet records for measuring dietary intakes in young girls. SUBJECTS/SETTING: Healthy 4- to 9-year-old girls (N=61; 6.5+/-1.6 years) were recruited from the Athens/Clarke county area in Georgia. DESIGN: Dietary intakes were measured using the Block98 FFQ and 3-day diet records, with nutrient analysis of the 3-day diet records conducted using the Food Processor computer program (ESHA; version 7.21, 1998, ESHA Research, Salem, OR). The Block98 FFQ was completed by a trained interviewer and parent, with input from the child, if able. Food models and portion size pictures were used to increase reporting accuracy. STATISTICAL ANALYSIS: Paired sample t tests and simple regression were conducted to determine whether the two diet instruments reported similar values for energy and macronutrients. RESULTS: Block98 FFQ overestimated intakes from 3-day diet records for energy (2,180+/-692 vs 1,749+/-328 kcal), protein (68.3+/-25.9 vs 57.9+/-14.8 g/day), carbohydrate (298.7+/-97.0 vs 244.7+/-46.1 g/day) and fat (83.6+/-30.5 vs 62.3+/-14.7 g/day) (P<.05). Furthermore, the nutrients assessed using the two different methods were only moderately correlated (range: r=0.40 to 0.55). APPLICATIONS/CONCLUSIONS: The Block98 FFQ agreed weakly to moderately with the 3-day diet records, and resulted in consistently higher intakes of all nutrients. These findings suggest that additional work is needed to develop a FFQ that reflects young children's energy and macronutrient intakes.     

Metabolisable energy consumption in the exclusively breast-fed infant aged 3--6 months from the developed world: a systematic review

The present study aimed to evaluate evidence on metabolisable energy consumption and pattern of consumption with age in infants in the developed world who were exclusively breast-fed, at around the time of introducing complementary feeding. We carried out a systematic review aimed at answering three questions: how much milk is transferred from mother to infant?; does transfer increase with the age of the infant?; and what is the metabolisable energy content of breast milk? Thirty-three eligible studies of 1041 mother--infant pairs reported transfer at 3--4 months of age, the weighted mean transfer being 779 (SD 40) g/d. Six studies (99 pairs) measured transfer at 5 months, with a weighted mean transfer of 827 (SD 39) g/d. Five studies (72 pairs) measured milk transfer at 6 months, reporting a weighted mean transfer of 894 (SD 87) g/d. Nine longitudinal studies reported no significant increases in milk transfer after 2--4 months. Twenty-five studies on breast-milk energy content were based on 777 mother--infant pairs. The weighted mean metabolisable energy content was 2.6 (SD 0.2) kJ/g. Breast-milk metabolisable energy content is probably lower, and breast-milk transfer slightly higher, than is usually assumed. Longitudinal studies do not support the hypothesis that breast-milk transfer increases markedly with age. More research on energy intake in 5--6-month-old exclusively breast-fed infants is necessary, and information on the metabolisability of breast milk in mid-infancy is desirable. This evidence should inform future recommendations on infant feeding and help to identify research needs in infant energy balance.     

Validation study of energy expenditure and intake during calorie restriction using doubly labeled water and changes in body composition

BACKGROUND: Clinical trials involving calorie restriction (CR) require an assessment of adherence to a prescribed CR with the use of an objective measure of energy intake (EI). OBJECTIVE: The objective was to validate the use of energy expenditure (EE) measured by doubly labeled water (DLW), in conjunction with precise measures of body composition, to calculate an individual's EI during 30% CR. DESIGN: Ten participants underwent 30% CR for 3 wk. During the last week (7 d), 24-h EE was measured in a respiratory chamber and simultaneously by DLW (EEDLW). EI was calculated from 7-d EE measured by DLW and from changes in energy stores (ES) (weight and body composition). Calculated EI was then compared with the actual EI measured in the chamber by using the following equations: calculated EI (kcal/d) = EEDLW + DeltaES, where DeltaESFM/FFM (kcal/d) = (9.3 x DeltaFM, g/d) + (1.1 x DeltaFFM, g/d), FM is fat mass, and FFM is fat-free mass. RESULTS: We found close agreement (R = 0.88) between EE measured in the metabolic chamber and EEDLW during CR. Using the measured respiratory quotient, we found that the mean (+/-SD) EE(DLW) was 1934 +/- 377 kcal/d and EE measured in the metabolic chamber was 1906 +/- 327 kcal/d, ie, a 1.3 +/- 8.9% overestimation. EI calculated from EEDLW and from changes in ES was 8.7 +/- 36.7% higher than the actual EI provided during the chamber stay (1596 +/- 656 kcal/d). CONCLUSIONS: DLW methods can accurately estimate 24-h EE during CR. Although the mean difference between actual and calculated EIs for the group was small, we conclude that the interindividual variability was too large to provide an assessment of CR adherence on an individual basis.     

Metabolizable energy of diets low or high in dietary fiber from cereals when eaten by humans

The metabolizable energy (ME) of two diets that differed in their content of dietary fiber (DF) from cereal products was measured in balance experiments in six human subjects. DF intake was 19.7 g/d with the low fiber diet and 48.3 g/d with the high fiber diet. Daily gross energy intakes were 2114 kcal (8845 kJ) and 2341 kcal (9795 kJ)/d with the low and the high fiber diets, respectively. DF contributed 83 kcal (347 kJ) and 203 kcal (849 kJ) to daily gross energy intake with the low and the high fiber diets, respectively, when heat of combustion of DF of 4.2 kcal (17.6 kJ)/g was assumed. Increasing the intake of DF resulted in an increase in stool weight and a greater fecal energy loss. Total energy losses were 253 kcal (1056 kJ) and 409 kcal (1711 kJ)/d with the low and the high fiber diets, respectively. ME provided by the low and the high fiber diet were 1861 kcal (7786 kJ) and 1932 kcal (8083 kJ)/d. The total increase in energy losses due to the increase in DF consumption exceeded the gross energy provided by additional DF. Compared with the low fiber diet, ME provided by protein and fat was decreased during the high fiber diet. Calculation of the apparent digestibility of DF indicated that fiber may have provided ME in the form of short-chain fatty acids during the low as well as during the high fiber intake. However, estimation of the amount of fecal gross energy indicated that available components of the diet, such as starch, must have been utilized incompletely during both experimental periods.     

Increasing dietary palmitic acid decreases fat oxidation and daily energy expenditure

BACKGROUND: Oleic acid (OA) is oxidized more rapidly than is palmitic acid (PA). OBJECTIVE: We hypothesized that changing the dietary intakes of PA and OA would affect fatty acid oxidation and energy expenditure. DESIGN: A double-masked trial was conducted in 43 healthy young adults, who, after a 28-d, baseline, solid-food diet (41% of energy as fat, 8.4% as PA, and 13.1% as OA), were randomly assigned to one of two 28-d formula diets: high PA (40% of energy as fat, 16.8% as PA, and 16.4% as OA; n = 21) or high OA (40% of energy as fat, 1.7% as PA, and 31.4% as OA; n = 22). Differences in the change from baseline were evaluated by analysis of covariance. RESULTS: In the fed state, the respiratory quotient was lower (P = 0.01) with the high OA (0.86 +/- 0.01) than with the high-PA (0.89 +/- 0.01) diet, and the rate of fat oxidation was higher (P = 0.03) with the high-OA (0.0008 +/- 0.0001) than with the high-PA (0.0005 +/- 0.0001 mg . kg fat-free mass(-1) . min(-1)) diet. Resting energy expenditure in the fed and fasting states was not significantly different between groups. Change in daily energy expenditure in the high-OA group (9 +/- 60 kcal/d) was significantly different from that in the high-PA group (-214 +/- 69 kcal/d; P = 0.02 or 0.04 when expressed per fat-free mass). CONCLUSIONS: Increases in dietary PA decrease fat oxidation and daily energy expenditure, whereas decreases in PA and increases in OA had the opposite effect. Increases in dietary PA may increase the risk of obesity and insulin resistance.     

Calculating the energy values of foods: towards new empirical formulae based on diets with varied intakes of unavailable complex carbohydrates.

A statistical analysis has been made by generalised linear regression of the relationship between the availability of digestible energy (DE) and the intakes of dietary gross energy (E) and of dietary 'fibre' or unavailable complex carbohydrate (U), for published observations on 43 human diets with varied intakes and sources of U (2-93 g daily) and varied intakes of E (7598-15104 kJ or 1816-3610 kcal daily). Simple formulae were devised also for the availability of metabolizable energy (ME) assuming urinary energy losses of 30 kJ or 7 kcal/g nitrogen (N) intake. For the calculation of DE and ME in mixed human diets with accuracy greater than obtained with previously published methods, the following linear formulae are proposed and their limitations discussed: DE (kJ) = 0.96E(kJ)-9U(g) ME (kJ) = 0.96E(kJ)-9U(g)-30N(g) DE (kcal) = 0.96E(kcal)-2U(g) ME (kcal) = 0.96E(kcal)-2U(g)-7N(g) The equations devised are used to identify atypical observations on faecal energy excretion, and their possible causes are considered. In particular diets high in whole-grain cereal cause faecal energy losses greater than predicted by these equations which is possibly explained by more carbohydrate reaching the colon than expected from current compositional analytical methods.     

Glycogen storage capacity and de novo lipogenesis during massive carbohydrate overfeeding in man

The metabolic balance method was performed on three men to investigate the fate of large excesses of carbohydrate. Glycogen stores, which were first depleted by diet (3 d, 8.35 +/- 0.27 MJ [1994 +/- 65 kcal] decreasing to 5.70 +/- 1.03 MJ [1361 +/- 247 kcal], 15% protein, 75% fat, 10% carbohydrate) and exercise, were repleted during 7 d carbohydrate overfeeding (11% protein, 3% fat, and 86% carbohydrate) providing 15.25 +/- 1.10 MJ (3642 +/- 263 kcal) on the first day, increasing progressively to 20.64 +/- 1.30 MJ (4930 +/- 311 kcal) on the last day of overfeeding. Glycogen depletion was again accomplished with 2 d of carbohydrate restriction (2.52 MJ/d [602 kcal/d], 85% protein, and 15% fat). Glycogen storage capacity in man is approximately 15 g/kg body weight and can accommodate a gain of approximately 500 g before net lipid synthesis contributes to increasing body fat mass. When the glycogen stores are saturated, massive intakes of carbohydrate are disposed of by high carbohydrate-oxidation rates and substantial de novo lipid synthesis (150 g lipid/d using approximately 475 g CHO/d) without postabsorptive hyperglycemia.