The existence of a subgroup of normal-weight individuals displaying obesity-related phenotypic characteristics was first proposed in 1981. These individuals were identified as metabolically obese but normal weight (MONW). It was hypothesized that these individuals might be characterized by hyperinsulinemia and (or) insulin resistance, as well as by hypertriglyceridemia and high blood pressure despite having a body mass index (BMI) < 25 kg/m2. Such characteristics could confer upon MONW subjects a higher cardiovascular risk; however, scientific data on MONW subjects are scarce since only 9 publications are directly related to this topic. Despite differences in the criteria for identifying MONW subjects and the small number of subjects involved in most of these studies, their consistent results indicate that: (i) the prevalence of the MONW syndrome ranges between 5% and 45%, depending on the criteria used, age, BMI, and ethnicity; (ii) when compared with control subjects, MONW subjects display an altered insulin sensitivity, a higher abdominal and visceral adiposity, a more atherogenic lipid profile, a higher blood pressure, and a lower physical activity energy expenditure; and (iii) MONW subjects are at higher risks for type 2 diabetes and cardiovascular diseases.

Mean daily water intake from fluids (WATER-FL) has proven to be difficult to measure because of a range of nonvalidated data collection techniques. Few questionnaires have been validated to estimate WATER-FL against self-reported diaries or urinary hydration markers, which may limit their objectivity. The goals of this investigation were ) to assess the validity of a 7-d fluid record (7dFLR) to measure WATER-FL (WATER-FL-7dFLR) through comparison with WATER-FL as calculated by measuring deuterium oxide (DO) disappearance (WATER-FL-DO), and ) to evaluate the reliability of the 7dFLR in measuring WATER-FL. Participants [ = 96; 51% female; mean ± SD age: 41 ± 14 y; mean ± SD body mass index (in kg/m): 26.2 ± 5.1] completed body water turnover analysis over 3 consecutive weeks. They completed the 7dFLR and food diaries during weeks 2 and 4 of the observation. The records were entered into nutritional software to determine the water content of all foods and fluids consumed. WATER-FL-DO was calculated from water turnover (via the DO dilution method), minus water from food and metabolic water. The agreement between the 2 methods of determining WATER-FL were compared according to a Bland-Altman plot at week 2. The test-retest reliability of 7dFLR between weeks 2 and 4 was assessed via intraclass correlation (ICC). The mean ± SD difference between WATER-FL-7dFLR and WATER-FL-DO was -131 ± 845 mL/d. In addition, no bias was observed ( = 0.484; = 0.006; = 0.488). When comparing WATER-FL-7dFLR from weeks 2 and 4, no significant difference (mean ± SD difference: 71 ± 75 mL/d; = 0.954; = 0.343) and an ICC of 0.85 (95% CI: 0.77, 0.90) was observed. The main findings of this study were that the use of the 7dFLR is an effective and reliable method to estimate WATER-FL in adults. This style of questionnaire may be extremely helpful for collecting water intake data for large-scale epidemiologic studies.

The kinetic parameters of absorption and distribution of ingested water (300 ml labeled with D2O; osmolality <20 mOsm kg−1) in the body water pool (BWP) and of its disappearance from this pool were estimated in 36 subjects from changes in plasma or urine deuterium to protium ratio (D/H) over 10 days using one- and two-compartment and a non-compartmental pharmacokinetic models (1-CM, 2-CM and N-CM which applied well to 58, 42 and 100% of the subjects, respectively). Compared with the volume and turnover of the BWP computed with the slope-intercept method (60.7 ± 4.1% body mass or 72.7 ± 3.2% lean body mass; turnover 4.58 ± 0.80 l day−1: i.e., complete renewal in ~50 days; n = 36), the values were accurately estimated with the N-CM and 1-CM and were slightly overestimated and underestimated, respectively, with the 2-CM (~7–8% difference, significant for water clearance only). Ingested water appeared in plasma and blood cells within 5 min and the half-life of absorption (~11–13 min) indicates a complete absorption within ~75–120 min. The 2-CM showed that in 42% of the subjects, ingested water quickly distributed within a central compartment before diffusing with a very short half-life (12.5 ± 4.3 min) to a peripheral compartment (18.5 ± 4.3 and 31.6 ± 6.4 L, respectively), which were in complete equilibrium within ~90 min. Pharmacokinetic analyses of water labeled with D2O can help describe water absorption and distribution, for which there is no well defined reference method and value; depending on the characteristics of the subjects and the drinks, and of environmental conditions.

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showed that ingestion of a glucose polymer (1.8 g min _1 ) increased exercise time from 192 to 252 min during cycling at 70 % of the maximum rate of oxygen uptake (◊J ,max ). In the study by McConell et al. (1999) exercise time at 69 % ◊J ,max increased from 152 to 199 min with ingestion of 287 g CHO. This phenomenon has also been described in animals (Dill et al. 1932; Bagby et al. 1978; Slentz et al. 1990). For instance, in the study by Slentz et al. (1990) running time to exhaustion, at 8 % gradient and 30 m min _1 , increased from 180 to 276 min in rats following administration of 1.44 g CHO. In addition, the ability to perform resistance exercise could also increase when CHO is ingested (Lambert et al. 1991;Haff et al. 2001). In the study by Haff et al. (2001), ingestion of 240 g CHO before and during intermittent isokinetic leg exercise significantly increased the total amount of work performed from 38.1 to 41.1 kJ.The effect of CHO ingestion on exercise time to exhaustion during prolonged exercise and on the ability to perform resistance exercise could be due to several factors including (1) an increased contribution of plasma glucose oxidation to the energy yield (Coyle et al. 1986), (2) muscle glycogen sparing (Tsintzas et al. 1996), (3) maintenance of blood glucose concentration, which could delay central fatigue (Davis et al. 1992) and has been shown to improve cognitive performance (Collardeau et al. 2001), (4) an increase in the exercise-induced activation of muscle pyruvate dehydrogenase (Tsintzas et al. 2000), (5) an attenuation of muscle and plasma ammonia accumulation (Snow et al. 2000) and (6) an improved muscle energy balance (McConnell et al. 1999). However, the mechanism(s), which could mediate improvements in exercise performance, associated with CHO administration : plasma glucose 11 ± 1.1, vs. 4.9 ± 0.2 mM with infusion of saline) (8 rats per group). Glucose infusion attenuated the reduction in submaximal peak dynamic force (55 % decrease vs. 70 % decrease in rats infused with saline alone, P < 0.05). In a third group of rats (n = 8), infusion of glucose 30 min after the start of stimulation partially restored submaximal peak dynamic force (P < 0.05). Maximum dynamic and isometric forces at the end of the period of stimulation were also higher (P < 0.05) in rats infused with glucose (4.0 ± 0.2 and 4.3 ± 0.2 N, respectively) than saline alone (3.0 ± 0.2 and 3.5 ± 0.2 N, respectively). The beneficial effect of glucose infusion on peripheral muscle force during prolonged stimulation was not associated with a reduction in muscle glycogen utilisation, nor with a reduction of fatigue at the neuromuscular junction, as assessed through maximal direct muscle stimulation (200 Hz for 200 ms; 150 V; pulse width, 0.05 ms). However, changes in M-wave peak-to-peak amplitude, duration and total area suggest that glucose infusion, and/or the associated increase in plasma insulin concentration, may prevent the deterioration of electrical properties of the muscle fibre membrane. Experimental Physiology (2...