Metabolic effects of a very low calorie diet in obese children and adolescents with special reference to nitrogen balance

Eight obese children and adolescents, mean age (+/- SD) 12.0 +/- 2.5 years, were treated for 3 weeks with a liquid formula very low calorie diet (VLCD), containing 320 kcal/1339 kj (44 g protein, 33 g carbohydrate, 0.9 g fat). Weight loss after 3 weeks was 8.0 +/- 1.8 kg resulting in 15.3 +/- 4.6% reduction of body overweight. During the dietary period no patient complained of hunger and no serious side effects were observed. Four patients achieved positive N-balance during the second week, all but one in the third week. Mean cumulative N-balance after 3 weeks was calculated to be -23.2 +/- 31.6 gN. Great interindividual variances were observed in the rate of N-loss during the course of the study. No significant correlation was found between cumulative N-balance and weight loss or initial body weight. Blood parameters remained unaffected, except for glucose and urea, which decreased slightly from 74.6 +/- 13.6 to 50.4 +/- 20.1 mg/dl and from 14.1 +/- 4.3 to 8.6 +/- 7.4 mg/dl, respectively. Uric acid concentrations increased slightly, three of eight patients had levels higher than 8 mg/dl and therefore were treated with allopurinol. Total serum protein decreased; serum albumin values did not change. The type of VLCD used in this study proved therapeutically useful in achieving rapid weight loss. Compared with VLCD containing 30% less protein and carbohydrate, a marked improvement of N-balance in 3 weeks could be achieved with the VLCD containing 1 g protein/kg IBW/day. This amount of protein seems to be necessary to obtain the nitrogen sparing effect in children and adolescents undergoing weight reduction with VLCDs.     

Nitrogen balance in obese patients receiving a very low calorie liquid formula diet.

Eleven obese patients were placed on a liquid formula diet containing 320 kcal (1.34 MJ), 31 g protein, 44 g oligosaccharides, 1.5 g fat, vitamins, and essential minerals for a period of 4 weeks under metabolic ward conditions. The diet was well tolerated, and mean weight loss was 2.49 kg/week during the 4-week period. Nitrogen excretion diminished in all patients during the period of treatment, but nitrogen balance remained slightly negative in most patients, mean daily deficit being 1.3 g N/day at the end of the study. The rate at which nitrogen was loss declined in a biphasic fashion, a slower second phase after an initial rapid period of adjustment to the diet. During the study a mean of 4.1 +/- 1.4% SD of calculated total body nitrogen was lost. Potassium excretion studies did not reveal significant potassium losses. The amount of nitrogen loss was correlated with the urinary creatinine excretion, suggesting that nitrogen loss during reduced dietary intake of protein is largely dependent on the size of the lean body mass.     

Lipids, lipoproteins and fatty acid composition in obese adolescents undergoing a very low calorie diet

Sixteen obese adolescents (mean +/- SD age: group I 12.5 +/- 2.1 and group II 12.0 +/- 2.5 years) were treated at least 3 weeks with two different very low calorie diet (VLCD) regimens. The VLCD in group I contained 33g proteins, 25.5g carbohydrates and 0.7g fat (240 kcal, 1004KJ) and in group II 44g protein, 33g carbohydrates and 0.9g fat (320 kcal, 1339KJ). After the 3 weeks treatment total serum cholesterol decreased from 180 +/- 34 mg/dl in group I and 184 +/- 34 mg/dl in group II respectively, to 125 + 16 mg/dl and 120 + 22 mg/dl. This fall was mainly due to the highly significant decrease of LDL-cholesterol. VLDL-cholesterol, HDL-cholesterol and triglycerides in group I remained almost unchanged. In group II triglycerides increased significantly from 81 +/- 19 mg/dl to 104 +/- 19 mg/dl and HDL-cholesterol decreased slightly. The LDL-C HDL-C- ratio in both groups improved considerably. Fatty acid composition of the serum lipids changed only slightly: In total serum linoleic acid levels declined slightly in group I and remained constant in group II. Linoleic acid content in cholesterylesters declined moderately in group I from 37.5 +/- 5.6% to 34.8 +/- 5.6% whereas arachidonic acid increased slightly in both groups. In phospholipids, oleic acid declined in both groups significantly, linoleic acid declined significantly in group I and arachidonic acid increased in group I significantly. Similar changes occurred in triglycerides. After 3 weeks treatment with a practically fat free alimentation no biochemical signs of essential fatty acid deficiency could be detected.     

Outcome attribution in a very low calorie diet program

Examined attributions for self-perceived failure or success among participants in a short- term very low calorie diet (VLCD) weight loss program. At 6 months follow-up, each subject was asked to attribute the outcome to internal factors, external factors, or to treatment pro- gram. Results showed that perceived failures and successes attributed about 50% of the out- come to internal factors. Perceived successes attributed outcome more to the treatment program than did perceived failures. Subjects also perceived the general success rates of VLCD treatments to be higher than those reported in the literature.     

Relationship between protein intake and nitrogen balance in obese patients on low energy diet

The effect of nitrogen intake on nitrogen balance was studied in six obese patients receiving low energy diets. They were given a control diet containing 2,000 kcal of energy and 80 g of protein for the first ten days. Then they were given Diet A with 1,100 kcal of energy and 70 g of protein for the next 2 weeks, followed by Diet B with 1,100 kcal of energy and 50 g of protein for 2 weeks. The relationship between nitrogen intake (X, mg/kg) and nitrogen balance (Y, mg/kg) during the low energy diet periods was statistically significant, with Y = 0.388X-60.32 (SD = 17.71, r = +0.67, n = 11, p less than 0.05). The nitrogen and protein requirements were estimated from this equation to be 201.1 mg/kg and 1.26 g/kg, respectively. In our experiment, the nitrogen balance in obese patients was well maintained although total energy was reduced to 1,100 kcal/day in Diet A. It is suggested that protein quantity in the diets should be taken into account when a low energy diet is used for the treatment of obesity.     

The effect of a high protein-low calorie diet on the energy expenditure of obese adolescents.

Resting energy expenditure (REE), and body composition, as fat-free mass (FFM) and fat mass, were determined in seven obese adolescents before and after weight loss of a mean 13.5 kg on an approximately 800 kcal/d (3349 kJ), high protein reducing diet regimen. Ideal body weight decreased from 166% to 142% in 8 weeks. There were no significant changes in total body potassium (TBK), extracellular water (ECW), intracellular water (ICW) or total body water (TBW) with weight loss. The REE (kcal/d) fell from 2034 +/- 392 (8514 +/- 1641 kJ) to 1762 +/- 453 (7376 +/- 1896 kJ) with weight loss (P < 0.05). However, when the REE was expressed as kcal/body weight there was no difference between before and after weight loss, 21.4 +/- 2.8 (90 +/- 21 kJ) and 21.6 +/- 4.5 (90 +/- 19 kJ). Similarly, when REE was examined in relation to FFM (kcal/kg) before and after weight loss, there were also no significant differences: 34.6 +/- 5.1 (145 +/- 21 kJ) and 32.1 +/- 7.9 (134 +/- 33 kJ).     

Dieting dilemmas: the very low calorie diet and surgical treatment programs.

Mean serum magnesium values with one standard deviation are presented for 224 women during pregnancy and 1559 women taking birth control pills, with 4145 women, aged 15-49 years, as controls. In addition, similar data are presented for 2,884 women, aged 50-74 years, after menopause. All these women were surveyed in the first National Health and Nutrition Examination Survey in the United States of America, 1971-1974 (NHANES I). Information on use of birth control pills is based on two questions taken from the NHANES I medical history interview. Pregnant women had significantly lower serum magnesium values than controls (nonpregnant and no birth control pills), regardless of age or race. Women on the pill also showed significantly lower serum magnesium values than other nonpregnant women of similar age, but the differences were much smaller than those between pregnant women and controls. Women older than 50 years (postmenopausal women) had significantly higher serum magnesium values than premenopausal women. These findings are compared with similar findings from other studies in the United States and other parts of the world.     

Effect of a very low calorie diet on the diagnostic category of individuals with binge eating disorder

OBJECTIVE: This study examined the factors associated with the diagnostic outcome of obese individuals with and without binge eating disorder (BED) 1 year after completing a very low calorie diet (VLCD) program. METHOD: Participants included 63 individuals with BED, 36 individuals with subthreshold BED, and 29 individuals with no binge eating symptoms. Diagnoses before and after VLCD were obtained using the Structured Clinical Interview for DSM-IV (SCID) interviews. The severity of psychiatric symptoms were assessed using various rating scales. RESULTS: Fifty-six percent (n = 36) of the participants who met criteria for BED at baseline did not meet diagnostic criteria 1 year later. None of the baseline factors were statistically associated with outcome. DISCUSSION: Although the main hypothesis was not supported, absence of a BED diagnosis at 12-month follow-up after a VLCD diet appears to be associated with less weight gain at 1-year follow-up regardless of baseline diagnosis.     

The effect of pretreatment eating patterns on the completion of a very low calorie diet

Pretreatment eating patterns of severely obese patients (n = 209) were investigated as predictors of attrition from a very low calorie diet. Subjects who ate three meals per day prior to the program were significantly more likely to complete the 6 month program than were those who reported skipping breakfast and consuming most of their calories in the evening. Those who ate mainly in the evening dropped out most frequently during the fasting phase of the program, possibly indicating an inability to conform to the requirements of a supplemented fast.     

Zinc and copper nutriture in obese men receiving very low calorie diets of soy or collagen protein

Balance studies for Zn and Cu were conducted over 40 days in 10 obese men housed in a metabolic balance unit. Two weight reduction diets providing 400 kcal and 100 g protein daily were administered; to five subjects, a collagen diet which was severely deficient in both Zn and Cu, and to another five subjects, a soy diet which provided a marginal intake of Zn and an adequate intake of Cu. Zn and Cu content of diets, plasma, red blood cells, urine, and feces were determined during eight 5-day periods. Balances were corrected for lean tissue catabolism or deposition. Holter ECG monitoring and measurement of the QTc interval were done on days 0 and 40. Both diets resulted in elevated plasma and red blood cell concentrations of Zn and Cu and in high urinary and fecal losses of Zn. By day 40, 6 of 10 subjects were in negative Zn balance. Urinary Zn was inversely correlated with measures of lean tissue catabolism. During each period, Cu balance was markedly positive in the soy-diet group and negative in the collagen-diet group. Shortening of prolonged QTc intervals was related to the Cu but not Zn status of the individual.     

Basal metabolism of obese adolescents: inconsistent diet and exercise effects

Effects of 20 wk of diet-plus-behavior (DB) therapy or exercise-plus-diet-plus-behavior (EDB) therapy on changes in basal energy expenditure (BEE) were studied in 36 obese male and female adolescents. BEE was assessed by open-circuit spirometry and body composition by hydrostatic weighing. Dietary restriction was based on the dietary-exchange program. Behavioral treatment included record-keeping, stimulus-control, and reinforcement techniques. EDB therapy included 50 min/d, 3 d/wk of aerobics. A time-by-group (2 X 3) repeated-measures ANOVA was used to analyze pre-to-postintervention differences between groups (DB, EDB, and control). Results revealed small but statistically significant (p less than 0.05) differences in body composition between the two experimental groups and control subjects. There were no differences in body composition between the DB and EDB groups, although all control subjects gained body mass (p less than 0.05). There was no group-by-time interaction for BEE. Moderate correlations of r = less than or equal to 0.61 were obtained between change in BEE and change in body composition for the subjects in the experimental groups.     

Short-term effects of a hypocaloric diet on nitrogen excretion in morbid obese women

OBJECTIVE: To determine whether the daily pattern of urine excretion of N wastes is affected by obesity and very low-calorie diets (VLCD). DESIGN: The plasma amino acid, urea and other energy parameters, as well as the urinary excretion of total nitrogen, urea and creatinine were studied in obese and normal-weight women. The obese women's data were obtained under hospital basal controlled conditions (8.1 MJ/day) and after 3 days of VLCD diet (1.9 MJ/day) controls were studied only once (5.8 MJ/day). The hourly excretion patterns of total N, urea and creatinine were determined from the composition of each bladder voiding. SUBJECTS: Twenty morbidly obese and 10 age-matched normal-weight control women. RESULTS: Plasma amino acid levels were higher in obese women, which showed a limited ability to metabolize amino acid hydrocarbon skeletons. Neither differences in the patterns between groups nor total 24 h values for urine volume were found. Total N and urea excretion diminished under VLCD diet. Hourly creatinine excretion showed a flat pattern and was higher in obese women than in the controls, VLCD diet diminished the amount of creatinine excreted in 24 h. CONCLUSIONS: The early change in energy availability that the creatinine excretion figures reflect may result from the energy conservation mechanisms induced in response to energy restriction. The early onset of this effect (3 days, and the extent of decrease (approximately 19%) also suggest that the impact of VLCD on the muscle energy budget of the obese is more marked than usually assumed.     

Clinical relevance of L-carnitine-supplemented total parenteral nutrition in postoperative trauma. Metabolic effects of continuous or acute carnitine administration with special reference to fat oxidation and nitrogen utilization

Carnitine-free total parenteral nutrition (TPN) is claimed to result in a carnitine deficiency with subsequent impairment of fat oxidation. The present study was designed to evaluate the possible benefit of carnitine supplementation on postoperative fat and nitrogen utilization. Sixteen patients undergoing total esophagectomy were evenly randomized and received TPN without or with L-carnitine supplementation (74 mumol.kg-1.d-1) during 11 postoperative days. On day 11, a 4-h infusion of L-carnitine (125 mumol/kg) was performed in both groups. The effect of supplementation was evaluated by indirect calorimetry, N balance, and repeated measurements of plasma lipids and ketone bodies. Irrespective of continuous or acute supplementation, respiratory quotient and fat oxidation were similarly maintained throughout the study in both groups whereas N balance appeared to be more favorable without carnitine. We conclude that carnitine-supplemented TPN does not improve fat oxidation or promote N utilization in the postoperative phase.     

Adherence rates to the Mediterranean diet are low in a representative sample of Greek children and adolescents

Data from studies in pediatric samples exploring adherence to the Mediterranean diet are scarce. The aim of the present work was to explore adherence to a Mediterranean diet pattern in a representative sample of Greek children and adolescents. The study sample (n = 1305, 3-18 y) was representative of the Greek pediatric population in terms of sex and age. Information on participants' sociodemographic, anthropometric, and lifestyle characteristics were collected through telephone interviews. Adherence to the Mediterranean diet guidelines for adults and to the general dietary guidelines for children was evaluated using KIDMED scores: the higher the score, the more favorable the dietary pattern. The Goldberg cut-off limits for the ratio of energy intake:basal metabolic rate were used to evaluate dietary underreporting and children were accordingly classified as low energy reporters (LER) or non-LER. Only 11.3% of children and 8.3% of adolescents had an optimal KIDMED score (>/=8). In adolescents, partial correlation analysis revealed a negative weak association between KIDMED and BMI (r = -0.092; P = 0.031), which remained significant in the non-LER subgroup (r = -0.137, P = 0.011). Multiple regression analysis revealed that higher KIDMED scores were associated, in non-LER children, with less time spent on sedentary activities (P = 0.002) and higher paternal education (P = 0.050), whereas in adolescents, with younger age (P = 0.001), less time spent on sedentary activities (P = 0.015), higher maternal education (P = 0.014), and higher eating frequency (P = 0.041). In conclusion, low adherence rates to the Mediterranean diet were observed in Greek children and adolescents; this evidence needs to be further explored regarding its impact on health and disease.