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Biomedical subjects

T B van Itallie

Publications and source records attributed to T B van Itallie.

6 recordsLinked to original sources
PubMed1984

Variability in body protein loss during protracted, severe caloric restriction: role of triiodothyronine and other possible determinants.

Six morbidly obese subjects were maintained in a metabolic ward for 64 days on liquid diets providing 600 to 800 kcal/day. Three received protein at a level of 1.5 g/kg desirable weight per day. The other three were given an identical diet in which half the protein was replaced by carbohydrate. Because there were no significant differences in either mean protein or mean fat losses between the two groups, the data on all six subjects were combined. Over the 64 days, the mean weight loss (+/- SEM) of the subjects per 1000 kcal deficit was 174.3 +/- 25.5 g. The composition of this weight loss was 36.0% water, 58.9% fat, and 5.1% protein. Although the rate of fat loss was relatively constant throughout the study, wide interindividual variations in cumulative protein (nitrogen) deficit were observed. Total nitrogen losses per subject ranged from 90.5 to 278.7 g. Cumulative nitrogen loss during the first 16 days tended to correlate negatively with initial mean fat cell size and positively with initial lean body mass. Most notable was the strong negative correlation between the size of the decrease in serum triiodothyronine over the 64-day study and the magnitude of the concurrent cumulative N deficit. During severe caloric restriction, one's ability to decrease circulating serum triiodothyronine levels may be critical to achievement of an adaptational decrease in body protein loss.

Adaptation, Physiological↗
PubMed1982

Caloric regulation in normal-weight men maintained on a palatable diet of conventional foods.

The spontaneous food intake of six normal-weight male volunteers was measured for 24 days while the subjects were inpatients on a metabolic unit. They were fed a palatable diet of conventional foods and were kept unaware that their food intake was being measured. On days 7-18 the caloric content of their diet was covertly reduced by 25% by substituting aspartame-sweetened analogues for all menu items containing sucrose. Subjects did not alter their food intake for 3 days. Then between days 4-6 on the aspartame diet, they increased their intake to compensate for 40% of the missing calories. Food intake stabilized at 85% of baseline and remained the same for the rest of the 12-day dilution period. Subjects did not show a shift in either sweetened or unsweetened food choices while their diet was being diluted. In adjusting for the missing calories, they simply ate more of their customary diet. The replacement of sucrose by aspartame tended to curb the weight gain observed on the baseline diet.

Adult↗
PubMed1979

Ingestive behavior and composition of weight change during cyproheptadine administration.

The effect of cyproheptadine on spontaneous energy intake was studied by means of an automated (liquid diet) food-dispensing apparatus in two nonobese adults confined to a metabolic ward. The experimental design included both single and double-blind periods. Throughout, the composition of daily weight change was determined by the energy-nitrogen balance method. While on cyproheptadine, both subjects exhibited increases in energy intake with the following average composition of weight gain: protein 16%, fat 14% and water 70% (first subject), and protein 5%, fat 49% and water 46% (second subject). The cyproheptadine-induced increase in energy intake was statistically significant in one of the subjects, who was at his desirable weight level at the outset. The other subject was underweight initially and tended to gain throughout the experiment, although rate of weight gain appeared to be more rapid during the periods of cyproheptadine administration. Energy output in both subjects remained fairly constant throughout. We conclude that cyproheptadine induces weight gain of 'normal' composition by stimulating increased energy intake.

Adult↗