SEARCH · PubMed Health

Results for “FATS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources

PubMed1994

[Fat distribution in Japanese women. Part 2. Fat thickness of extremities and classification of fat distribution of whole body].

The first object of this paper was to follow the previous paper in clarifying the characteristics of the fat distribution on the extremities. The subcutaneous fat thickness was measured at 64 points on the upper extremity and on 129 points on the lower extremity. The difference of the fat distribution between obese subjects and lean subjects was mainly observed on the back of the upper arm and the thigh. The second object of this paper was to clarify the characteristics of the fat distribution on both the trunk and the extremities and to study the factors which contribute to the fat distribution of the whole body. Average subcutaneous fat thickness over the body was 7.8 mm, and the standard deviation was 1.2 mm. Types of fat distribution of the whole body were classified by principal component analysis of average fat thickness in the 8 regions. The first component was the size factor which expressed the amount of fat on the whole body. The second component showed the contrast of fat distribution in the lower extremities and in the breast, abdomen, back and arms. These two components accounted for 90.79% of the variance of fat distribution. Measuring points, which showed high correlation coefficient with the average fat thickness of the whole body, were abdomen, subscapular, back, thigh and side breast.

Adipose Tissue↗

PubMed1997

A low-fat diet supplemented with monounsaturated fat results in less HDL-C lowering than a very-low-fat diet.

OBJECTIVE: The purpose of this study was to compare the effects of a very-low-fat diet with a low-fat diet supplemented with monounsaturated oil on plasma lipid levels in subjects with hypercholesterolemia. DESIGN: The 8-week study was divided into one 2-week baseline diet and two 3-week intervention periods in a randomized crossover design. SETTING: The study was conducted in an outpatient setting at the Deakin Institute of Human Nutrition, Deakin University, Geelong, Australia. SUBJECTS: Twenty-four free-living subjects with hypercholesterolemia participated in and completed the study. INTERVENTION: After a 2-week baseline period of a self-selected diet, subjects were assigned to one of two dietary interventions: a very-low-fat (10% of energy from fat), high-carbohydrate diet or a low-fat (26% of energy from fat) diet supplemented with olive oil and an olive oil-based margarine. MAIN OUTCOME MEASURES: Lipid measurements included total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglyceride concentrations. Plasma cholesteryl esters were measured to monitor compliance. STATISTICAL ANALYSES: A paired t test was used to assess differences between treatment periods for each subject. The dependence of the difference between treatment periods on the covariates of age, sex, initial cholesterol concentration, and energy intake was analyzed using repeated measures and analysis of covariance. RESULTS: The low-fat diet supplemented with monounsaturated fat resulted in significantly less high-density lipoprotein cholesterol lowering than the very-low-fat diet (P=.005). Both interventions resulted in significant reductions in both low-density lipoprotein cholesterol and total cholesterol compared with the baseline diet. APPLICATIONS: This study suggests that a low-fat diet enriched with olive oil provides advantages over a very-low-fat diet in the control of serum lipoproteins among persons with hypercholesterolemia.

Adult↗

PubMed1999

Sex difference in measures of body fatness and the possible difference in the effect of dietary fat on body fatness in men and women.

OBJECTIVES: To examine the sex difference in anthropometric measures of body fatness and to explore the possibility that diet may have differential effects on body fatness in men and women. DESIGN: Prospective study design. SETTING: The first and second China Health and Nutrition Survey conducted in 1989 and 1991, respectively. SUBJECTS: 1449 men and 1683 women age 20-35 y at the baseline (1989) survey. METHODS: Anthropometric measures of body fatness in men and women were compared. Statistical methods were used to explore the potential difference in the effect of dietary fat on body fatness in men and women. RESULTS: Measures of body fatness, especially peripheral fatness, differed markedly between men and women in this study sample. Statistical analysis suggested that the effect of dietary fat on body fatness may be different in men compared to women. CONCLUSIONS: Sexual dimorphism in body fatness has important implications for both clinical and epidemiologic research of obesity. The possibility that diet may have differential effect on body fatness in men and women needs to be investigated.

Adipose Tissue↗

PubMed1982

[Serum cholesterol and liver deiodase activity in rats of different body composition after low or high fat diet. Effect of a feeding change in fat-rich to fat-poor diet and the reverse or of an iodine deficient diet].

Male Wistar rats with an average age of 28 weeks received diets high (HFD: 50% fat) or low (LFD: 3% fat) in fat content. Rats were restricted on iodine intake by feeding pure diets without iodine addition. The relative degree of iodine shortage of rats was estimated by 131I-uptake. PB131I and ETR. Serum cholesterol, whole body lipid content and liver deiodinase activity of LFD (control)- and HFD-rats were analyzed. A change of diet feeding from high to low fat content and vice versa took place to discriminate the effect of diet fat from body fat content of rats on serum cholesterol and deiodinase activity. HFD fed rats with high body fat content showed at iodine restriction the same serum cholesterol concentration as relative lean LFD-animals. Post feeding change from diet rich to poor on fat and vice versa at 4 weeks the obese animals have lost body fat only 10-20% at calorie restriction and exhibit higher serum cholesterol levels and equal liver deiodinase activity as lean, now fat rich fed control animals. Heavy HFD-rats fed on fat rich diet for 22 weeks have approximately two times higher liver lipid content as light LFD-animals. Because liver lipid content and deiodinase activity between light LFD- and heavy HFD-rats before and after change of diet feeding are equal, a relation between liver lipid content and enzyme activity is discussed.

Animals↗

PubMed1989

[Fecal fat excretion rate in patients with Crohn's disease--comparison of a diet containing 50 g/day of fat with elemental diet with an addition of 50 g/day butter fat].

Fecal fat excretion rate was determined by the method of Van de Kamer in 31 patients with Crohn's disease and six healthy controls, when fed by the diet containing 50 g/day of fat. Patients with jejuno-ileitis and those with partial and extensive resection showed a significantly greater excretion rate compared with patients with ileitis and healthy controls, however, there was no significant difference between patients with ileitis and healthy controls. In this study, the fecal excretion rate was less than 10 g/day in non-operated cases. Our results seems to be smaller than those in previous studies from the western countries. Fecal fat excretion rate was determined in 12 patients with non-operated Crohn's disease and six healthy controls, when fed by the additional 50 g/day butter fat during the elemental diet. With ingestion of the additional 50 g/day butter fat during elemental diet, fecal fat excretion rate was significantly increased in the patients with non-operated Crohn's disease than the results of the diet containing 50 g/day fat, but not significantly changed in the healthy controls. This result suggest that determination of fecal fat excretion rate with fed by the additional 50 g/day butter fat during elemental diet is a useful test for detecting a mild fat malabsorption in non-operated Crohn's disease.

Adolescent↗

PubMed1987

[Experimental study on pedicle fat grafts after laminectomy: comparison of pedicle fat and free fat grafts].

Scar formation adherent to the dura and nerve roots causes recurrent symptoms following laminectomy. Free and pedicle fat grafts have been performed in low-back surgery as a preventive measure. An experimental study in rats was designed to compare pedicle fat grafts and free fat grafts after wide laminectomy, for efficacy in preventing scar formation and for effects on the spinal cord. The following results were obtained. 1) Dense scar formation over the dura and degeneration of the cord were seen at control laminectomy sites. 2) Free fat grafts, examined at 2 and 4 weeks postoperatively, showed death of portions of the graft, whereas pedicle fat grafts always demonstrated the presence of living fat. 3) At 4 months postoperatively, pedicle fat grafts were statistically superior to free fat grafts, which showed scarring over the dura and degeneration of the cord. In conclusion, pedicle fat grafts were more effective in preventing dural scar formation and protecting the cord than free fat grafts.

Adipose Tissue↗

PubMed1986

Epicardial fat cell size, fat distribution and fat infiltration of the right and left ventricle of the heart.

An investigation was carried out on the hearts of 34 autopsied adults to determine fat cell size, fat distribution and fat infiltration at 10 defined points over the right and left ventricular wall. The data found were correlated with the body weight and the fat cell size of other regions of fatty tissue. The size of the fat cells at the defined sampling points over the right and left ventricular wall showed no statistically significant difference overall. On the other hand, in one and the same person statistically significant differences in epicardial fat cell size could nevertheless exist depending on the localisation. A positive correlation existed between body weight on the one hand, and on the other hand, fat cell size, epicardial fatty tissue height, and fat infiltration of the right ventricle. With increasing body weight the size of the fat cells of the other regions of fatty tissue investigated, especially of the abdominal skin, omentum majus and mesenteric root, augmented to a greater extent than that of the epicardial fat cells.

Adipose Tissue↗

PubMed1998

[Estimation of body composition based on total body water determination using phenazone for assessment of body fat gain in cattle. 2. Relationship between body fat content and back fat thickness].

Back fat thickness was measured at six points in 251 beef heifers aged 3 to 17 months, in 27 beef bulls aged 15 months and in 200 Holstein dairy cows of different age. This was paralleled by estimation of body fat content based on total body water analysis. All groups of animals showed the same pattern of back fat thickness for the measuring points investigated, which lead to the result of one optimum measuring point for determination of back fat thickness. The correlation coefficients between back fat thickness and body fat content were estimated to be between 0.80 and 0.87 for all groups investigated. Change in back fat thickness by 1 mm corresponded to gain or loss of around 5 kg body fat in all animal groups. Therefore it is possible to make concrete assessments of body fat content on the basis of back fat thickness.

Adipose Tissue↗

PubMed2000

The role of dietary fat in body fatness: evidence from a preliminary meta-analysis of ad libitum low-fat dietary intervention studies.

The role of high-fat diets in weight gain and obesity has been questioned because of inconsistent reports in the literature concerning the efficacy of ad libitum low-fat diets to reduce body weight. We conducted a meta-analysis of weight loss occurring on ad libitum low-fat diets in intervention trials, and analysed the relationship between initial body weight and weight loss. We selected controlled trials lasting more than 2 months comparing ad libitum low-fat diets with a control group consuming their habitual diet or a medium-fat diet ad libitum published from 1966 to 1998. Data were included from 16 trials with a duration of 2-12 months, involving 1728 individuals. No trials on obese subjects fulfilled the inclusion criteria. The weighted difference in weight loss between intervention and control groups was 2.55 kg (95% CI, 1.5-3.5; P < 0.0001). Weight loss was positively and independently related to pre-treatment body weight (r = 0.52, P < 0.05) and to reduction in the percentage of energy as fat (0.37 kg/%, P < 0.005) in unweighted analysis. Extrapolated to a BMI of about 30 kg/m2 and assuming a 10% reduction in dietary fat, the predicted weight loss would be 4.4 kg (95% CI, 2.0 to -6.8 kg). Because weight loss was not the primary aim in 12 of the 16 studies, it is unlikely that voluntary energy restriction contributed to the weight loss. Although there is no evidence that a high intake of simple sugars contributes to passive overconsumption, carbohydrate foods with a low glycaemic index may be more satiating and exert more beneficial effects on insulin resistance and cardiovascular risk factors. Moreover, an increase in protein content up to 25% of total energy may also contribute to reducing total energy intake. In conclusion, a low-fat diet, high in protein and fibre-rich carbohydrates, mainly from different vegetables, fruits and whole grains, is highly satiating for fewer calories than fatty foods. This diet composition provides good sources of vitamins, minerals, trace elements and fibre, and may have the most beneficial effect on blood lipids and blood-pressure levels. A reduction in dietary fat without restriction of total energy intake prevents weight gain in subjects of normal weight and produces a weight loss in overweight subjects, which is highly relevant for public health.

Body Mass Index↗

PubMed2004

Two important exceptions to the relationship between energy density and fat content: foods with reduced-fat claims and high-fat vegetable-based dishes.

OBJECTIVE: To test the hypothesis that many foods with reduced-fat (RF) claims are relatively energy-dense and that high-fat (HF) vegetable-based dishes are relatively energy-dilute. DESIGN: Nutrient data were collected from available foods in Melbourne supermarkets that had an RF claim and a full-fat (FF) equivalent. Nutrient analyses were also conducted on recipes for HF vegetable-based dishes that had more than 30% energy from fat but less than 10% from saturated fat. The dietary intake data (beverages removed) from the 1995 National Nutrition Survey were used for the reference relationships between energy density (ED) and percentage energy as fat and carbohydrate and percentage of water by weight. STATISTICS: Linear regression modelled relationships of macronutrients and ED. Paired t-tests compared observed and predicted reductions in the ED of RF foods compared with FF equivalents. RESULTS: Both FF and RF foods were more energy-dense than the Australian diet and the HF vegetable-based dishes were less energy-dense. The Australian diet showed significant relationships with ED, which were positive for percentage energy as fat and negative for percentage energy as carbohydrate. There were no such relationships for the products with RF claims or for the HF vegetable-based dishes. CONCLUSION: While, overall, a reduced-fat diet is relatively energy-dilute and is likely to protect against weight gain, there appear to be two important exceptions. A high intake of products with RF claims could lead to a relatively energy-dense diet and thus promote weight gain. Alternatively, a high intake of vegetable-based foods, even with substantial added fat, could reduce ED and protect against weight gain.

Commerce↗

PubMed2002

The influence of the type of dietary fat on postprandial fat oxidation rates: monounsaturated (olive oil) vs saturated fat (cream).

OBJECTIVE: To compare postprandial whole-body fat oxidation rates in humans, following high-fat (43% of total energy) mixed breakfast meals, of fixed energy and macronutrient composition, rich in either monounsaturated fat (MUFA) from extra virgin olive oil or saturated fat (SFA) from cream. DESIGN: Paired comparison of resting metabolic rate (RMR), thermic effect of a meal and substrate oxidation rates following consumption of isocaloric breakfast meals, differing only in the type of fat, administered in random order 1-2 weeks apart. SUBJECTS: Fourteen male volunteers, body mass index (BMI) in the range 20-32 kg/m(2), aged 24-49 y and resident in Melbourne, Australia, were recruited by advertisement in the local media or by personal contact. MEASUREMENTS: Body size and composition was determined by anthropometry and dual energy X-ray absorptiometry (DEXA). Indirect calorimetry was used to measure RMR, thermic effect of a meal, post-meal total energy expenditure and substrate oxidation rate. Blood pressure and pulse rates were measured with an automated oscillometric system. Fasting and 2 h postprandial glucose and insulin concentrations and the fasting lipid profile were also determined. RESULTS: In the 5 h following the MUFA breakfast, there was a significantly greater postprandial fat oxidation rate (3.08+/-4.58 g/5 h, P=0.017), and lower postprandial carbohydrate oxidation rate (P=0.025), than after the SFA breakfast. Thermic effect of a meal was significantly higher (55 kJ/5 h, P=0.034) after the MUFA breakfast, in subjects with a high waist circumference (HWC > or = 99 cm) than those with a low waist circumference (LWC<99 cm). This difference was not detected following the SFA breakfast (P=0.910). CONCLUSION: If postprandial fat oxidation rates are higher after high MUFA, rather than SFA meals, then a simple change to the type of dietary fat consumed might have beneficial effects in curbing weight gain in men consuming a relatively high-fat diet. This may be particularly evident in men with a large waist circumference.

Absorptiometry, Photon↗

PubMed2006

Opposed-phase MRI for fat quantification in fat-water phantoms with 1H MR spectroscopy to resolve ambiguity of fat or water dominance.

OBJECTIVE: The purpose of the study was to quantify the fat fraction in nine fat-water phantoms containing 0-80% fat using opposed-phase imaging with the qualitative guidance of 1H MR spectroscopy (MRS), which was used by observer 1 to visually assess the sizes of the water and fat peaks to apply two alternative mathematic formulas for the calculation of the fat fraction. In addition, the fat fraction was also quantified directly with 1H MRS as an independent method by two observers (observers 2 and 3). CONCLUSION: The fat fraction calculated with opposed-phase imaging (FF(OPI)) and that calculated with 1H MRS (FF(MRS)) correlated well with the known fat fractions of the phantoms (FF(P)): r = 0.99 for FF(OPI); p < 0.0001 and r = 0.96-0.98 for FF(MRS); p < 0.001, for observers 2 and 3, respectively. Opposed-phase imaging should be combined with 1H MRS to ensure accurate quantification of the fat fraction.

Animals↗

PubMed1993

Abdominal wall fat index, estimated by ultrasonography, for assessment of the ratio of visceral fat to subcutaneous fat in the abdomen.

PURPOSE: To establish a new index of regional fat distribution using ultrasonography for assessment of the ratio of the visceral fat area (V) to the subcutaneous fat area (S) (V/S ratio). SUBJECTS AND METHODS: The subjects examined were 62 patients (23 males and 39 females); 51 patients had hyperlipidemia and 11 patients had glucose intolerance. The mean body mass indices ranged from 20.3 to 42.9. The mean age of the patients was 44 +/- 13 years. The thicknesses of the preperitoneal fat layer (P) and subcutaneous fat layer (S) in the abdomen were measured by ultrasonography and the P/S ratio was calculated. The V/S ratio was obtained with radiographic computed tomography. RESULTS: Of the various P/S ratios examined, the ratio of the maximum thickness of preperitoneal fat to the minimum thickness of subcutaneous fat was most closely correlated with the V/S ratio (r = 0.746, p < 0.0001). This ratio was termed the abdominal wall fat index (AFI). AFI was positively correlated with serum triglyceride levels and negatively correlated with high-density lipoprotein cholesterol (r = -0.312, p < 0.05), whereas the V/S ratio was correlated with triglyceride levels. AFI was positively correlated with basal insulin levels in both men and women. CONCLUSION: These results suggest that AFI measured by ultrasonography may be a new indicator of visceral fat deposition, and may reflect metabolic disorders such as lipid metabolism and glucose metabolism disorders.

Abdominal Muscles↗

PubMed1971

Electrical coupling between fat cells in newt fat body and mouse brown fat.

White fat from the newt, Triturus pyrrhogaster, fat body, and brown fat from the interscapular fat pad of newborn mice have been tested for the presence of low-resistance intercellular junctions. 42 pairs of amphibian fat cells and 15 pairs of mammalian brown fat cells were found to be "electrically coupled." In most of these cases intracellular deposition of a dye, Niagara Sky Blue: 6B, was used to supplement and confirm direct observations of impalements. Coupling was often difficult to find in both preparations, but the mechanical disturbance of the tissue during the preparative procedures may have uncoupled many cells. The fact that, in both types of fat, coupling was observed between cells separated by one or more other cells suggests that coupling may be more widespread in vivo. Electron microscopy (provided by Dr. J. -P. Revel and Mrs. K. Wolken) of the brown fat revealed frequent intercellular junctions resembling "gap junctions" but possibly lacking the substructure usually visible with colloidal lanthanum infiltration. The results are discussed in relation to current ideas about the exchange of regulatory molecules via low-resistance junctions and about the control of brown fat by hormones and nerves.

Adipose Tissue↗

PubMedDate not supplied

[Body fat and fat mass-fat free mass ratio estimated by bioelectric impedance in the nutritional evaluation of women 35-55 years of age].

BACKGROUND: Nutritional evaluation during pre-menopause and menopause plays an important role in assessing the changes taking place in a woman's body, a comparison being drawn in this study between the parameters body fat and body fat-muscle ratio (BFMR) estimated by impedancemetry and the body mass index (BMI) for defining nutritional status and body composition. METHODS: A cross-sectional descriptive study. By random sampling (health card basis), thirty women within the 35-55 age range were selected and then evaluated regarding the relationship between body fat and fat mass (FM)-fat free mass (FFM) ratio (FM/FFM = BFMR) and the BMI, different means of estimating body fat distribution: waist and iliac region circumferences, waist-hip and iliac region-hip ratios and iliac region and sagittal diameters; systolic (SBP) and diastolic blood pressures (DBP) and serum levels of glucose, cholesterol, HDL-cholesterol and triglycerides. RESULTS: The percentage of body fat was highly correlated (p < 0.001) with BMI (r = 0.919), waist (r = 0.866) and iliac region (r = 0.841) circumferences and sagittal (r = 0.783) and iliac region (r = 0.772) diameters, and less highly with glycemia (r = 0.385; p = 0.036) and the SBP (r = 0.497; p = 0.005) and DBP (r = 0.582; p = 0.001). The BFMR showed similar results, no being significantly related to any biochemical parameter. 46.7% of the obese women as per their percentage of body fat (> 33%) had a BMI of under 30. CONCLUSIONS: The estimating of the body fat and BFMR parameters among women within the 35-55 age range supplements the nutritional evaluation made by means of the BMI, although in order to define their true figures in this evaluation, the reference values must for the population as a whole must be determined.

Adipose Tissue↗

PubMed2004

Failure of fat cell proliferation, mitochondrial function and fat oxidation results in ectopic fat storage, insulin resistance and type II diabetes mellitus.

BACKGROUND: It is widely accepted that increasing adiposity is associated with insulin resistance and increased risk of type II diabetes. The predominant paradigm used to explain this link is the portal/visceral hypothesis. This hypothesis proposes that increased adiposity, particularly in the visceral depots, leads to increased free-fatty acid flux and inhibition of insulin-action via Randle's effect in insulin-sensitive tissues. OBJECTIVES: In this review, limitations of this paradigm will be discussed and two other paradigms that may explain established links between adiposity and insulin resistance/diabetes will be presented. (A) Ectopic fat storage syndrome. Three lines of evidence support this concept. Firstly, failure to develop adequate adipose tissue mass (also known as 'lipodystrophy') results in severe insulin resistance and diabetes. This is thought to be the result of ectopic storage of lipid into liver, skeletal muscle and the pancreatic insulin-secreting beta cell. Secondly, most obese patients also shunt lipid into the skeletal muscle, the liver and probably the beta cell. The importance of this finding is exemplified by several studies demonstrating that the degree of lipid infiltration into skeletal muscle and liver highly correlates with insulin resistance. Thirdly, increased fat cell size is highly associated with insulin resistance and the development of diabetes. Increased fat cell size may represent the failure of the adipose tissue mass to expand and therefore to accommodate an increased energy influx. Taken together, these observations support the 'acquired lipodystrophy' hypothesis as a link between adiposity and insulin resistance. Ectopic fat deposition is therefore the result of additive or synergistic effects including increased dietary intake, decreased fat oxidation and impaired adipogenesis. (B) Endocrine paradigm. This concept was developed in parallel with the 'ectopic fat storage syndrome' hypothesis. Adipose tissue secretes a variety of endocrine hormones such as leptin, interleukin-6, angiotensin II, adiponectin and resistin. From this viewpoint, adipose tissue plays a critical role as an endocrine gland, secreting numerous factors with potent effects on the metabolism of distant tissues. CONCLUSIONS: The novel paradigms of ectopic fat and fat cell as an endocrine organ probably will constitute a new framework for the study of the links between our obesigenic environment and the risk of developing diabetes.

Adipocytes↗

PubMed1966

Studies on lipogenesis in vivo. Effect of dietary fat or starvation on conversion of [14]glucose into fat ad turnover of newly synthsized fat.

1. Lipogenesis was studied in vivo by giving mice 250mg. meals of [U-(14)C]glucose and measuring the disposition and incorporation of label. About 48% of the (14)C dose was eliminated as (14)CO(2) in the first 2hr. At 60min. after administration, 1.0, 1.9 and 11.9% of the dose was recovered as liver glycogen, liver fatty acid and carcass fatty acid respectively. Of the [(14)C]glucose converted into fat in the epididymal pads about 90% was present as glyceride fatty acid and 10% as glyceride glycerol. 2. Hepatic synthesis of fatty acid was depressed by dietary fat to a much greater extent than was synthesis outside the liver. Both feeding with fat and starvation decreased the proportion of the label taken up by adipose tissue present as fat (triglyceride) and increased the proportion of triglyceride label present as glyceride glycerol. These results are consistent with the hypothesis that the primary action of both these conditions in decreasing fat synthesis is to inhibit synthesis of fatty acids. 3. Turnover of body fat labelled in vivo from [U-(14)C]glucose was estimated from the decline in radioactivity measured over the first 24hr. of the experiment. The half-life of liver and extrahepatic fatty acids (excluding epididymal fat) was 16hr. and 3 days respectively. In contrast, no measurable decrease in radioactivity of the fatty acids of epididymal fat was observed for 7 days after administration of the [U-(14)C]glucose.

Adipose Tissue↗

PubMed1977

Carcass components at first estrus of rats on high-fat and low-fat diets: body water, protein, and fat.

Carcass analysis data show that weanling rats fed high-fat (HF) and low-fat (LF) diets until the day of first estrus had similar body compositions at estrus, although the HF rats had estrus significantly earlier and at a lighter body weight (P less than 0.01) than the LF-diet rats. Total water as percent of wet weight, protein as percent of wet weight, and the water/protein ratios of the HF- and LF-diet rats did not differ significantly, whereas the absolute amounts of body water and protein of the two diet groups differed significantly (P less than 0.01), in accord with means (+/- SEM) of total body water as percent of wet weight were 66.2 +/- 0.3% for the HF rats and 66.4 +/- 0.3% for the LF-diet rats, whereas the mean absolute total body water for the two diet groups was 69.7 +/- 2.2 g and 81.1 +/- 2.4 g, respectively (P less than 0.01). Carcass fat of the HF rats, 15.6 +/- 1.0 g, was identical with that of the LF-diet rats, 15.6 +/- 0.9 g. The HF rats were therefore relatively fatter, 14.6 +/- 0.6 wet weight %, than the LF-diet rats, 12.6 +/- 0.4 wet weight % (0.05 greater than P greater than 0.01). The percentage of water in the fat-free wet weight of the HF rats, 77.5 +/- 0.3%, was significantly (P less than 0.01) greater than that of the LF-diet rats, 76.1 +/- 0.3%. These data and the high percentages of total water of body weight show that at first estrus the HF- and LF-diet rats had not as yet attained an adult body composition, similar to the human female at menarche. Within each diet group, the percentages of total water/body weight, protein/wet weight and fat/wet weight, or fat/dry weight, did not change significantly with increasing age of estrus, whereas each absolute carcass component--body water, protein, and fat--increased significantly with increasing age of estrus. The carcass data support G.C. Kennedy's hypothesis that a metabolic signal, related to fat stores, is a signal for puberty in the rat and are in accord with the hypothesis that a critical body composition of fatness is necessary for estrus in the rat, as in the human female. The greater relative fatness of the HF-diet rats may be associated with higher levels of estrogen in the HF rats than in the LF-diet rats.

Age Factors↗