PURPOSE: Consuming 375–500 ml of water 30 min before a meal has been shown to reduce energy intake in older, but not younger adults. This study investigated the effects of ingesting a water preload immediately pre-meal (<1 min before eating) on within-meal ad libitum energy intake in non-obese young males. METHODS: Fourteen healthy males [mean (SD) age 27 (3) years, height 1.83 (0.05) m, body weight 80.47 (9.89) kg, body fat 17.5 (4.0) %, body mass index 24.0 (2.5) kg/m²] completed a familiarisation trial and two experimental trials in randomised counterbalanced order. Subjects arrived at the laboratory overnight fasted and consumed an ad libitum porridge breakfast. Immediately prior to the meal, subjects consumed either a 568 ml (1 pint) water preload (preload trial) or no preload (control trial). Visual analogue scale questionnaires to assess hunger, fullness and satisfaction were completed before and after the meal in both trials, as well as after the water preload. RESULTS: Ad libitum energy intake was greater (P < 0.001) during control [2551 (562) kJ] than preload [1967 (454) kJ]. Ad libitum water intake was also greater (P < 0.001) during control [318 (226–975) ml] than preload [116 (0–581) ml]. The water preload increased fullness and satisfaction and decreased hunger compared to pre-trial (P < 0.001) and the control trial (P < 0.001). CONCLUSION: This study demonstrates that consumption of a 568 ml water preload immediately before a meal reduces energy intake in non-obese young males. This might therefore be an effective strategy to suppress energy intake in this population and possibly assist with weight management.

Ad libitum (AL) feeding of rats leads to obesity and increased result variability, as well as premature morbidity and mortality. It may also alter metabolism and responses to foreign compounds. Moderate dietary restriction (DR) reduces these untoward effects without compromising the sensitivity of rodent bioassays. The diet board (DB) is a novel method for achieving moderate DR in group housing. Food pellets are firmly attached into grooves in an aspen board, and rats have to gnaw the wood in order to eat. Food is available continuously, but due to the effort involved rats eat less. This study simulated a chronic safety test to assess the long-term effects of DB feeding. A total of 146 male and female outbred Sprague-Dawley rats, nine weeks old at onset, were housed in groups of three and fed either AL or with DBs for two years. Food and water consumption were measured at six time points. The rats were weighed every one to two weeks. Body and tibial lengths and epididymal fat weight were measured at necropsy. Modified body mass index was calculated at five time points after one year of age. DB feeding reduced body weight and fat tissue moderately, more so in males. DB males ate less than AL males, but no differences were seen in the total food consumption in the females. There was no consistent difference in the within-group variations of the measured parameters. DB is a workable DR method, albeit some modification could enhance and standardize its DR effects, especially in female rats.

Desert mammals often experience scarcity of drinking water and food for prolonged periods. In this study, the first long-term acclimation experiment in a non-domesticated desert-adapted ungulate, we investigated the mechanisms used by the Arabian oryx Oryx leucoryx, to adjust its physiology to progressive food and water restriction over 5 months, an experimental regimen and time course chosen to mimic what it typically experiences between spring and late summer in the desert. At the end of the acclimation period, oryx consumed less than one and half of food and water of animals in the control group and lost 8.2±2.6% of their initial body mass. Experimental animals reduced their mass-specific resting metabolic rate (RMR) and total evaporative water loss (TEWL) by 16.2 and 25.7%, respectively, and maintained a digestive efficiency of about 70%. We found no support for the idea that reduced RMR in oryx correlated with a decreased thyroid hormone concentration in plasma. At the end of the 5 months acclimation, oryx continued to mobilize fatty acids to fuel metabolism, and did not use protein breakdown as a major source of gluconeogenesis. Oryx in the experimental group reduced their water intake by 70% and maintained constant plasma osmolality. They adjusted their water budget by reducing mass-specific TEWL, increasing urine osmolality and reducing urine volume by 40%, and excreting feces with <50% water content. Oryx have an unusually low TEWL compared with other arid-zone ungulates; both hydrated and water-deprived individuals have TEWL values, 51.7 and 39.3%, respectively, of allometric predictions for arid-zone ungulates.

Objective: To study whether eating or physical-activity (PA) habits differ between obese and non-obese monozygotic (MZ) co-twins independent of genetic effects. Methods: Rare MZ pairs discordant for obesity (n=14, body mass index difference 5.2±1.8 kg m–2) and weight-concordant control pairs (n=10, 1.0±0.7 kg m–2), identified through a population-based registry of 24–28-year-old twins (n=658 MZ pairs), completed 3-day food and PA diaries and eating behavior questionnaires. Each twin was asked to compare his/her own eating and PA patterns with the co-twin's behavior by structured questionnaires. Accuracy of energy intake was validated by doubly labeled water. Results: Non-obese co-twins consistently reported that their obese twin siblings ate more food overall, consumed less healthy foods and exercised less than the non-obese co-twins do. However, no differences in energy intake (9.6±1.0 MJ per day vs 9.8±1.1 MJ per day, respectively) in the food diaries or in the mean PA level (1.74±0.02 vs 1.79±0.04, respectively) in the PA diaries were found between obese and non-obese co-twins. A considerable underreporting of energy intake (3.2±1.1 MJ per day, P=0.036) and overreporting of PA (1.8±0.8 MJ per day, P=0.049) was observed in the obese, but not in the non-obese co-twins. Conclusions: On the basis of rare MZ twin pairs discordant for obesity, the co-twin assessments confirmed substantial differences in eating and PA behavior between obese and non-obese persons. These may be overlooked in population studies using food and PA diaries because of considerable misreporting by the obese.

Accurate assessments of a target population&rsquo;s energy intake (EI) are essential to prevent poor nutritional status. However, self-reported dietary records (DRs) or food frequency questionnaires (FFQs) are not always accurate, thereby requiring validation and calibration studies. This study aimed to validate the EI estimated by a FFQ using the doubly labeled water (DLW) method. Participants were 109 Japanese older adults (50 women and 59 men) aged 65&ndash;88 years. The EI was obtained by a DR and 47-item FFQ over 1 year. The total energy expenditure (TEE) was measured by DLW for ~2 weeks. EI was significantly lower than TEE (p < 0.01); ratios of EI assessed by DR and FFQ against TEE were 0.91 &plusmn; 0.17 and 0.82 &plusmn; 0.22, respectively. TEE was significantly and moderately correlated with the EI estimated by the DR (r = 0.45, p < 0.01) and FFQ (r = 0.37, p < 0.01). Furthermore, the EI correlation coefficients estimated by DR and the FFQ in this study were not significantly different (p = 0.46). The EI/TEE ratio was significantly and negatively correlated with the body mass index (BMI). In conclusion, EI estimated with a DR or FFQ modestly correlated with TEE, and calibrating EI with a developed equation in this study can attenuate the underestimation of EI.

The high intake of dietary sodium (Na⁺) has been associated with obesity and insulin resistance, sparking the hypothesis that the consumption of salty foods affects food intake (FI) and postprandial blood glucose (BG) response. Therefore, we conducted 2 randomized repeated-measures experiments to examine the acute effects of the Na⁺ content of solid food and beverage on FI, water intake (WI), subjective appetite, thirst, and BG. FI and WI were measured at ad libitum pizza test meals; appetite, thirst, and BG were measured at baseline and at regular intervals before and after meals. In the first experiment, 16 males (mean body mass index (BMI), 22.2 kg·m⁻²) consumed a low-Na⁺ (71 mg) bean preload (300 kcal) with or without 740 mg or 1480 mg of added Na⁺ 120 min prior to the pizza meal. Participants ate 116 kcal more at the test meal after consuming beans with 740 mg of added Na⁺ than after beans with 1480 mg of added Na⁺. In the second experiment, 19 males (mean BMI, 23.2 kg·m⁻²) consumed a low-Na⁺ (62 mg) tomato beverage (73 kcal) with or without 500, 1000, 1500, or 2000 mg of added Na⁺ 30 min prior to a pizza meal. The beverage with 2000 mg of added Na⁺ led to higher WI during the pizza meal than the beverage with 500 mg of added Na⁺. However, compared with the control conditions (no added Na⁺), added Na⁺ treatments had no effect on dependent measures in either experiment. In conclusion, the acute intake of Na⁺, in a solid or liquid form, did not affect short-term subjective ratings of appetite or thirst, ad libitum FI or WI, or BG in healthy young men.

The usefulness of replacement of caloric sugars by low-calorie sweeteners (LCS) for weight management has been questioned on the grounds that the uncoupling of LCS sweet taste and dietary energy may confuse physiological mechanisms, leading potentially to higher energy and sugar intake. The aim of the present study was to determine whether LCS beverages compared to water, when consumed with meals, differ in their effects on energy and food intake in acute trials and after long-term habituation. Ad libitum food intake of 166 (80 women; 86 men) healthy non-obese adults (BMI between 19 and 28 kg/m2), infrequent consumers of LCS was measured in four 2-consecutive-day testing sessions (Day 1 in the laboratory, Day 2 free-living). During the first 3 sessions, held one-week apart, participants were required to drink either water or commercial non-carbonated LCS lemonade (330 ml) with their main meals (randomised cross-over design). On Day 1, motivational ratings were obtained using visual analogue scales and ad libitum food intakes (amounts and types of foods selected) were measured using the plate waste method. On Day 2, participants reported their ad libitum intakes using a food diary. After Session 3, participants were randomly assigned to the LCS habituation group or to the water control group. The habituation (660 ml LCS lemonade daily vs 660 ml water) lasted 5 weeks. The fourth and final test session measured food intakes and motivational ratings after habituation. Water and LCS beverage did not differ in their effects on total energy intake, macronutrient intakes or the selection of sweet foods and on motivational ratings. Similar results were obtained in both LCS-naïve and LCS-habituated individuals.

Background: Measurements of dietary intake in obese and overweight populations are often inaccurate because food intakes are underestimated. Objective: The purpose of this study was to evaluate the validity of the combined use of observer-recorded weighed-food records and 24-h snack recalls in estimating energy intakes in overweight and obese individuals. Design: Subjects were 32 healthy women and 22 healthy men with mean body mass indexes (in kg/m2) of 29.5 and 30.3, respectively. Energy intake (EI) was measured over 2 wk in a university cafeteria. No restrictions were made on meal frequency or EI. To document food consumed outside the cafeteria, 24-h snack recalls were conducted before meals. Energy expenditure (EE) was measured with the doubly labeled water (DLW) method (EEDLW). Energy balance was determined by measuring body weight at the beginning and end of the 2-wk period. Results: The mean EI in the women (10.40 +/- 1.94 MJ/d) and men (14.37 +/- 3.21 MJ/d) was not significantly lower than the EEDLW in the women (10.86 +/- 1.76 MJ/d) and men (14.14 +/- 2.83 MJ/d). The mean EI represented 96.9 +/- 17.0% and 103 +/- 18.9% of the measured EE for women and men, respectively. There were no significant changes in weight in the group as a whole or by sex at the end of the testing period; the men lost 0.23 +/- 1.58 kg and the women lost 0.25 +/- 1.09 kg. Conclusion: The combination of observer-recorded food records and 24-h snack recalls is a valid method for measuring EI in overweight and obese individuals.

The usefulness of replacement of caloric sugars by low-calorie sweeteners (LCS) for weight management has been questioned on the grounds that the uncoupling of LCS sweet taste and dietary energy may confuse physiological mechanisms, leading potentially to higher energy and sugar intake. The aim of the present study was to determine whether LCS beverages compared to water, when consumed with meals, differ in their effects on energy and food intake in acute trials and after long-term habituation. Ad libitum food intake of 166 (80 women; 86 men) healthy non-obese adults (BMI between 19 and 28 kg/m²), infrequent consumers of LCS was measured in four 2-consecutive-day testing sessions (Day 1 in the laboratory, Day 2 free-living). During the first 3 sessions, held one-week apart, participants were required to drink either water or commercial non-carbonated LCS lemonade (330 ml) with their main meals (randomised cross-over design). On Day 1, motivational ratings were obtained using visual analogue scales and ad libitum food intakes (amounts and types of foods selected) were measured using the plate waste method. On Day 2, participants reported their ad libitum intakes using a food diary. After Session 3, participants were randomly assigned to the LCS habituation group or to the water control group. The habituation (660 ml LCS lemonade daily vs 660 ml water) lasted 5 weeks. The fourth and final test session measured food intakes and motivational ratings after habituation. Water and LCS beverage did not differ in their effects on total energy intake, macronutrient intakes or the selection of sweet foods and on motivational ratings. Similar results were obtained in both LCS-naïve and LCS-habituated individuals.