Influence of a monotonous food on body weight regulation in humans

Four human subjects were fed ad lib with a bland diet for a period of 3 weeks. Their body weight decreased by 3.13 kg during this period. It was observed that the shift of the palatability response to sucrose solutions induced by a gastric glucose load (alliesthesia) was not affected by such a reduction of body weight. This result was compared to a previous experiment showing a decreased alliesthesia after a body weight loss due to the restriction of a palatable diet. These results confirm the role of the palatability of the diet on the maintenance of a body weight level and provide evidence for an interaction between the two factors in determining the oral satiation process.     

Fluoxetine-maintained obese humans: effect on food intake and body weight

The effects of fluoxetine on food intake, body weight, and mood of obese individuals was examined in a 16-week inpatient/outpatient study. Six male and eight female obese volunteers began the study (four male and five females completed all phases of the study). They lived in a residential laboratory during three one-week inpatient periods separated by a 5-week and an 8-week outpatient period. Following an initial 4-day placebo baseline, participants were maintained on fluoxetine (60 mg/day) for the remainder of the study. Food intake parameters (total daily energy intake, macronutrient intake, mean number of eating bouts, interbout interval), body weight, subjective effects, and task performance were measured several times during the day during inpatient periods; food intake questionnaires were completed daily during the outpatient periods. Fluoxetine significantly reduced daily energy intake derived from fat, carbohydrate, and protein by decreasing the mean number of eating bouts per day throughout the study. No other food intake parameter was affected. Body weight was significantly reduced after 7 weeks, but not after 16 weeks of daily fluoxetine administration. These results indicate that fluoxetine reduced food intake for at least 16 weeks in nondepressed obese individuals without specifically affecting carbohydrate intake. Weight that was lost during the first few weeks of daily fluoxetine administration was subsequently regained even though food intake remained reduced. Therefore, fluoxetine maintenance does not appear promising as a sole long-term therapy for obesity.     

Food intake,body weight,and sweetness preferences over the menstrual cycle in humans

The body weight and reported food intake of 34 women were measured at the midpoint of the follicular and luteal phases of the menstrual cycle. Both body weight and reported food intake were significantly higher during the luteal phase than during the follicular phase. In addition, sweetness (sucrose) preferences were measured on both occasions before and after a glucose load. Examination of the pre- to post-load changes revealed a significant decline during the luteal phase and the absence of such a decline in the follicular phase. The results were discussed in terms of the influence of ovarian hormones on food regulation and carohydrate metabolism.     

Regulation of the body weight of the european hamster during the annual cycle

Summary The effects of body weight losses of European Hamsters after food deprivation were investigated at various periods of the year. In November and December normally occurs a body weight decrease which can be accelerated by food deprivation. When the animals have again access to food, they either reduce their weight loss or regain weight according to the importance of the previous weight loss. Weight gain after food deprivation proceeds at rates which vary with the season; the rate is faster in spring and summer than in autumn and winter. It is concluded that body weight is regulated and that two characteristics of the regulating mechanism (somatostat) undergo circannual variations: the level of the set point and the rate of weight loss compensation.With the technical assistance of Miss A. Koch (C.N.R.S.).     

Regulation of arterial blood pressure in humans during isometric muscle contraction and lower body negative pressure

Previous studies have shown that the blood pressure response to isometric handgrip remains unchanged during reductions in preload induced by lower body negative pressure (LBNP). The purpose of the present study was to assess the beat-by-beat haemodynamic mechanisms allowing for precise control of mean arterial pressure (MAP). We have followed the cardiovascular variables involved in the regulation of MAP during isometric handgrip with and without additional application of LBNP during defined periods of the ongoing contraction. Sixteen subjects participated. Mean arterial blood pressure (MAP), heart rate (HR), stroke volume (SV), cardiac output (CO), blood flow velocity in the brachial artery, acral skin blood flow, as well as total (TPR) and local (LPR) peripheral resistance were continuously recorded/calculated before, during and after 2 min of handgrip both with and without concomitant LBNP. The main finding was that MAP increased at the same rate and to the same absolute level whether or not LBNP was applied. A uniform increase in MAP was observed even though the cardiovascular variables evolved differently in the periods with and without LBNP. At the onset of LBNP at –20 mmHg, there was a transient drop in MAP and a transient increase in HR, but within seconds, MAP was regulated back to the slope caused by the isometric handgrip proper. CO and SV, which were declining gradually, showed an additional marked but gradual reduction upon LBNP application. At the same time, both LPR and TPR increased markedly and continuously. In summary, the increase in MAP during isometric handgrip remained essentially unchanged by LBNP-induced alterations in preload. The increase in MAP was caused by a marked increase in peripheral resistance. This supports the concept of a central set point, continuously regulated upwards as long as the isometric handgrip persists. Furthermore, it reveals a considerable flexibility in the cardiovascular control mechanisms used to achieve the desired arterial pressure.     

The influence of age, sex, race, and body habitus on kidney weight in humans

The impact of age, sex, race, and body build on kidney weight was examined in 357 normal individuals who died suddenly. Mulivariate, stepwise linear-regression analysis demonstrated that kidney weight was best predicted by body surface area. Age, sex, and race had no additional impact on kidney weight once differences in body build were taken into account. Similar results were obtained with heart and liver weights. These findings were confirmed using a second, independent paired sample of 16 lean and 16 massively obese adults. Body build-associated changes in kidney weight were paralleled by changes in both glomerular and tubulointerstitial areas. Body build is the major determinant of kidney weight and nephron size in normal humans.     

Lipectomy, body weight, and body weight set point in rats.

Adult, Wistar male rats were lipectomized or sham lipectomized. The food-hoarding behavior was measured repeatedly and plotted against the animals' body weights. Body weight set point was estimated as the intercept of regression line of hoarding with the X axis. Body fat content was measured with a TOBEC body composition analyzer. Body weight set point, fat content, and girth were obtained initially, after surgery, and after recovery. The hoarding threshold was lowered for 2 weeks after surgery, from 561 +/- 20 to 512 +/- 19 g (lipectomized), and from 582 +/- 15 to 558 +/- 14 g (sham lipectomized). After a 4-week recovery, all rats reached their prelipectomy body weight set point and regained their initial body fat. Five weeks after surgery, no significant difference was found between the body weight set points of lipectomized and sham-lipectomized rats. This indicates that the body weight set point was not mainly modulated by fat depots. The transient lowering of the set point is thought to be due to surgical stress.     

Heart weight as a function of body weight in mammals

Linear regression analysis was carried out on logarithmically transformed heart weight and body weight data in 104 mammalian species. It was shown that heart weight varies as the 0.98 power of body weight over essentially the whole mammalian weight range. The coefficient of correlation between heart weight and body weight is 0.99. Student's test was employed to compare the slopes of the several regression lines as between male and female animals, and as between terrestrial and aquatic mammals. In neither case were the differences in slope found to be statistically significant (df greater than 177, p less than 0.5).     

Regulation of local sweating in sleep-deprived exercising humans

Summary Thermoregulatory sweating [total body (m _sw,b), chest (m _sw,c) and thigh (m _sw,t) sweating], body temperatures [oesophageal (T _oes) and mean skin temperature (T _sk)] and heart rate were investigated in five sleep-deprived subjects (kept awake for 27 h) while exercising on a cycle (45 min at approximately 50% maximal oxygen consumption) in moderate heat (T _air andT _wall at 35° C. Them _sw,c andm _sw,t were measured under local thermal clamp (T _sk,1), set at 35.5° C. After sleep deprivation, neither the levels of body temperatures (T _oes,T _sk) nor the levels ofm _{sw, b},m _{sw, c} orm _{sw, t} differed from control at rest or during exercise steady state. During the transient phase of exercise (whenT _sk andT _sk,1 were unvarying), them _{sw, c} andm _{sw, t} changes were positively correlated with those ofT _oes. The slopes of them _{sw, c} versusT _oes, orm _{sw, t} versusT _oes relationships remained unchanged between control and sleep-loss experiments. Thus the slopes of the local sweating versusT _oes, relationships (m _{sw, c} andm _{sw, t} sweating data pooled which reached 1.05 (SEM 0.14) mg·cm^–2·min^–1°C^–1 and 1.14 (SEM 0.18) mg·cm^–2·min^–1·°C^–1 before and after sleep deprivation) respectively did not differ. However, in our experiment, sleep deprivation significantly increased theT _oes threshold for the onset of bothm _{sw, c} andm _{sw, t} (+0.3° C,P<0.001). From our investigations it would seem that the delayed core temperature for sweating onset in sleep-deprived humans, while exercising moderately in the heat, is likely to have been due to alterations occurring at the central level.     

Relationship between perilipin gene polymorphisms and body weight and body composition during weight loss and weight maintenance

BackgroundGenetic variation in the perilipin (PLIN) gene may play a role in the etiology and treatment of obesity.ObjectiveTo examine different polymorphisms in the PLIN gene in relation to body-weight regulation.Methods118 subjects followed a 6 wk VLCD, followed by 1 year weight maintenance. Body-weight (BW), body-composition, leptin concentration, and polymorphisms of the PLIN gene: PLIN1:rs2289487, PLIN4:rs894160, PLIN6:rs1052700, PLIN5:rs2304795 and PLIN7:rs 2304796 were determined.ResultsBW loss during VLCD was 7.0 ± 3.1 kg (p < 0.05), and BW regain was 3.7 ± 1.4 kg (p < 0.05), including changes in body mass index (BMI), waist-circumference, body-composition and leptin concentrations (p < 0.05).Linkage disequilibria were observed between PLIN1 and PLIN4: D' > 0.9, r² = 0.72; PLIN5 and PLIN7: D' > 0.9, r² = 0.85.In men, body weight, BMI, waist circumference, body fat, leptin concentrations were significantly lower for the haplotype of PLIN1 (C-alleles) and PLIN4 (A-alleles). In women weight loss and loss of fat mass were larger for the haplotype of PLIN1 (C-alleles) and PLIN4 (A-alleles). For PLIN6 genotypes body weight and body fat were lower for homozygotes of the minor allele (T/T) in the men; in the women leptin concentrations were lower.The haplotype of PLIN5 and PLIN7 consisting of A/G and G/G of PLIN5 and A/A of PLIN7 showed a reduction in FM: 5.9 ± 0.6 kg vs 3.1 ± 0.4 kg, % body fat: 5.5 ± 0.6% vs 2.2 ± 0.2%, and leptin: 20.5 ± 10.8 ng/ml vs 12.9 ± 6.7 ng/ml over time in the women (p < 0.05).ConclusionSince the haplotype of the minor alleles PLIN1–4, PLIN5–7 and PLIN6, was related to body-weight regulation at a lower level of body-weight in the men as well in the women we conclude that the PLIN1–4, 6, and 5–7 locus appears as a genetic influencer of obesity risk in humans.     

The relationship of organ weight,body weight and age in mice

A method is described which permits the examination of the influences of increasing age and body weight on organ weights. Polynomial multivariate analysis is performed by computer, and the predicted organ weight values permit the construction of three dimensional graphs which show the influence on organ weight of all combinations of age and body weight. The application of the method will allow the physical biology of organisms to be determined with considerable precision over their life span.     

Influence of chronic sublethal cyanide on body weight in neonatal swine: Implications for humans consuming cassava (Manihot esculenta)

The consumption of CN^? containing foods (particularly cassava) is pervasive among millions of humans throughout the tropics, yet very little is known about the long-term implications of this dietary pattern on growth. In this study Liberian (West African) levels of dietary cyanide (CN^?) intakes were replicated in juvenile swine for 24 weeks to quantify the effects of specified, chronic, sublethal doses of this metabolic poison on body weight. Twelve female and male littermates were partitioned into a control (Ø mg CN^?) and 3 treatment groups (1.2, 0.7, or 0.4 mg CN^? per kg body weight per day). CN^? treatments depressed absolute weight gain in a dose-dependent manner with significant differences apparent as early as week 12. Thyroid hormones T₃ and T₄ and fasting blood glucose values were evaluated at 6-week intervals. T₃ levels were ostensibly suppressed and blood glucose values elevated with increasing CN^? ingestion. Serum thiocyanate (SCN^?), the major metabolite of sublethal CN^? ingestion, was positively correlated with CN^? intake loads (r = 0.83, P < 0.01). Hypothesized physiological foundations for these observations and theoretical implications for human growth are elaborated.     

Changes in body weight and body composition during the menstrual cycle

Objectives

The general perception is that menstrual cycle is a factor related to body weight and body composition fluctuations in women. The lack of a standardized methodology of the so far conducted studies has led to controversial results. The aim of the current study is to identify if there are any changes in body weight and body composition during the menstrual cycle.

Methods

In the current study measurements of body weight, circumferences, skinfolds and body composition with bioelectrical impedance analysis were conducted twice per week in 42 women during their menstrual cycle.

Results

Body weight was found to be statistically significantly higher during menstruation compared to the first week of the menstrual cycle by 0.450 kg, which could be attributed to a statistically significant increase of 0.474 kg observed in extracellular water. No other statistically significant changes were observed regarding body composition.

Conclusions

An increase of approximately 0.5 kg was observed during women's menstrual cycle, mostly due to extracellular fluid retention at menstruation days. These findings could be taken into account to interpret body weight and composition periodic fluctuations in women of reproductive age.     

Alexithymia and body weight in obese patients

The authors evaluated severely obese patients to determine whether being far different in body shape from the accepted standard may cause obese people to develop alexithymic personality traits. They evaluated the food- and weight-related attitudes in obesity surgery patients and in long-term follow-up of those who had previously had biliopancreatic diversion (BPD) for obesity. One quarter of the obese patients had alexithymic characteristics without any modification following stable weight loss, a rate of alexithymia similar to that observed in the nonclinical population. Furthermore, the frequency of alexithymia and the patients' scores on the Toronto Alexithymia Scale were similar in obese and post-BPD individuals. The authors concluded that being obese by itself does not influence the presence of alexithymic personality traits. However, they suggest that the improvement in food-related and weight-related attitudes following stable weight loss may be different in alexithymic and in nonalexithymic obese patients.     

Effect of increased growth rate during the suckling period on subsequent body weight and muscle weight to body weight ratio

The effect of increased growth rate during the suckling period on subsequent body growth rate and muscle weight to body weight (MW/BW) ratio was examined in inbred and outbred male and female mice. Growth rate during the suckling period was increased by reducing litter size to 4 pups within six hours of birth. Body weight, MW/BW ratio, and dry weight to wet weight (DW/WW) ratio for the soleus, tibialis anterior, extensor digitorum longus, biceps brachii, and heart muscles were measured at 4, 8, 16, and 24 weeks of age. The results indicate that increasing growth rate during the suckling period results in an increased body weight at 24 weeks of age in outbred male and female mice; whereas, in inbred male and female mice body weight is greater at 4 weeks of age but by 8 weeks of age the mice raised in normal litters have "caught up" with those raised in small litters. MW/BW ratio is increased in several muscles during the suckling period but returns to normal during the post weaning period.