Theodore B. Van Itallie

Contributions of age, sex and degree of fatness on preferences and magnitude estimations for sucrose in humans

Abstract Comparisons of magnitude estimate scaling for six suprathreshold concentrations (0.056–1.0 M) of sucrose by fifth graders, college students, and elderly persons revealed a steeper function for the children but no differences between the other two groups. Higher preferences were reported by males than by females for the sweeter concentrations and degree of fatness was inversely correlated with preference. These data suggest that deficits in sensory coding are not produced by old age and that important differences in sweet preference exist between human males and females.

A new method for estimation of body composition in the live rat.

Abstract Measurement of total body electrical conductivity (TOBEC) has been used to estimate lean and fat content of meat based on the principle that electrical conductivity of lean tissue is far greater than that of fat. This approach was used to estimate body composition of live rats. An instrument designed for commercial analysis of ground meat (DjMe 100) was used to measure TOBEC in 30 male Sprague-Dawley rats (197-433 g). Individual TOBEC values were obtained in 20 seconds and repeated twice for each rat. The animals were then killed with ether, hair was shaved, lungs collapsed and body density measured hydrostatically. Carcasses were homogenized and analyzed for fat, nitrogen, and water. A high correlation was found between TOBEC and lean body mass by densitometry (r = .97) and between TOBEC and fat-free mass derived from direct carcass analysis (r = .97). Rats weighing up to 450 g could be accommodated in this particular instrument. Measurement of TOBEC should prove useful in estimating body composition and monitoring its changes in live rats and other small laboratory animals.

Genetic obesity: Estrogenic influences on the body weight and food intake of lean and obese adult Zucker (fa/fa) rats

Abstract The effects of chronic estrogen withdrawal and subsequent hormone replacement on the feeding and body weight of adult lean and genetically obese Zucker rats were investigated. Following confirmation of a delay in the vaginal canalization of the fatty rat, subgroups of each genotype received either ovariectomy or sham surgery (Experiment 1). One hundred days later all subjects were injected subcutaneously (SC) with 1.0 μg of estradiol benzoate (EB) daily for 16 treatment days (Experiment 2A). A second series of daily 2.0 μg EB injections was administered intraperitoneally (IP) for 1 week (Experiment 2B). The first experiment revealed that ovariectomy produced overeating and similar weight gains in both genotypes. In the second experiment, SC hormone treatment completely reversed ovarian obesity in lean animals but failed to alter the food intake or weight gain of fatty rats. IP administration of EB depressed the feeding of fatty and lean animals to a comparable degree but a reduction in weight gain was observed only in the lean rats. These findings are discussed in light of current theories of estrogenic modulation of energy balance.

Nutritional assessment of hospital patients: New methods and new opportunities

Recently, two new methods (total body electrical conductivity [TOBEC] and bioelectrical impedance analysis [BIA]) have become available for the rapid, safe, and convenient estimation of total body water in hospital patients. Despite these clear advantages, the clinical usefulness of the TOBEC and BIA methods in patient diagnosis and care is likely to be restricted by illness‐related changes in the hydration of the lean body and in the distribution of water between the intracellular and extracellular water compartments. If these methods can be refined so as to permit their measurement of extracellular water as rapidly as they now measure total body water, the ability of clinicians to assess and monitor the nutritional and metabolic status of their hospital patients will be greatly enhanced.

Sham feeding is inhibited by dietary-induced obesity in rats ☆

A group of six female, albino rats were maintained on a cafeteria diet of cookies, milk, and elevated-fat (shortening), rat-chow mixture and rat chow while a similar group received only rat chow ad lib for 17 weeks. When the groups differed significantly in mean body weight (obese-387.5 g, controls-287.2 g; p less than 0.001), gastric fistulas were implanted in each animal. After recovery, the rats were adapted to a liquid diet and assessed for sham feeding. Control-fed, normal-body-weight subjects showed substantial sham feeding when ingesting the Vivonex with the fistulas open compared to fistula-closed intake; meal frequency, meal size (apart from the initial meal) and total food intake were significantly increased while the satiety ratios following each meal were significantly decreased. Obese animals showed no significant increased feeding and satiety ratios were unreliably altered; while normal-body-weight controls increased 4-hr food intakes by 93% and halved their mean satiety ratios the obese animals showed an 8% increase in 4-hr food intake and only a 22% decrease in mean satiety ratios. We offer the hypothesis that, when animals are induced to become obese by palatable and varied diets which are then terminated, the anorexia produced is independent of gastrointestinal interactions inasmuch as that anorexia extends to sham feeding.

An overview of therapy for morbid obesity.

Therapeutic approaches to morbid obesity include starvation, very low calorie diets, “liquid protein” diets, ketogenic diets, and surgical procedures. None of these is ideal, and all have the potential for recidivism and complications. Although conservative measures should be tried first, the potential hazards of obesity warrant drastic treatment.

Food-motivated behavior in the old-carbon enriched rat: Relationship to maintenance of carbohydrate stores during food deprivation

Abstract Rats with depot fat enriched with odd-carbon fatty acids by feeding a diet containing triundecanoin (C11:0) as the major fat source maintain significantly higher concentrations of liver glycogen and serum glucose during starvation than do rats fed a conventional fat. Following food deprivation the odd-carbon enriched (OCE) rats exhibit significantly lower response rates than their nonenriched controls when tested on high density variable interval reinforcement schedules (CRF, VI 15, VI 30) but perform as well as controls under a low density variable interval reinforcement schedule (VI 60) or during extinction. Differences in performance between OCE and control animals can be obtained following fasts of up to 96 hr; deprivation intervals over which significant differences in plasma glucose levels can be observed. These findings suggest that the OCE rat is as motivated for food as the control but satiates at a faster rate. In view of the special ability of the OCE animal to resist carbohydrate depletion during a fast, these experiments indicate a specific and important role for carbohydrate status in determining performance of deprived animals on food motivated tasks.