K-L. Catherine Jen

Short-Term Effect of Eggs on Satiety in Overweight and Obese Subjects

Objective: To test the hypotheses that among overweight and obese participants, a breakfast consisting of eggs, in comparison to an isocaloric equal-weight bagel-based breakfast, would induce greater satiety, reduce perceived cravings, and reduce subsequent short-term energy intake. Subjects: Thirty women with BMI’s of at least 25 kg/M2 between the ages of 25 to 60 y were recruited to participate in a randomized crossover design study in an outpatient clinic setting. Design: Following an overnight fast, subjects consumed either an egg or bagel-based breakfast followed by lunch 3.5 h later, in random order two weeks apart. Food intake was weighed at breakfast and lunch and recorded via dietary recall up to 36 h post breakfast. Satiety was assessed using the Fullness Questionnaire and the State-Trait Food Cravings Questionnaire, state version. Results: During the pre-lunch period, participants had greater feelings of satiety after the egg breakfast, and consumed significantly less energy (kJ; 2405.6 ± 550.0 vs 3091.3 ± 445.5, Egg vs Bagel breakfasts, p < 0.0001), grams of protein (16.8 ± 4.2 vs 22.3 ± 3.4, Egg vs Bagel breakfasts, p < 0.0001), carbohydrate 83.1 ± 20.2 vs 110.9 ± 18.7, Egg vs Bagel breakfasts, p < 0.0001), and fat 19.4 ± 5.1 vs 22.8 ± 3.2, Egg vs Bagel breakfasts, p < 0.0001) for lunch. Energy intake following the egg breakfast remained lower for the entire day (p < 0.05) as well as for the next 36 hours (p < 0.001). Conclusions: Compared to an isocaloric, equal weight bagel-based breakfast, the egg-breakfast induced greater satiety and significantly reduced short-term food intake. The potential role of a routine egg breakfast in producing a sustained caloric deficit and consequent weight loss, should be determined.

The benefits of early intervention in obese diabetic patients with FBCx: a new dietary fibre.

Obesity and diabetes have become epidemic in the US. Dietary fibres have been reported to reduce the absorption of dietary fat, prevent weight gain, and reduce blood lipid levels. In the current double‐blind study, obese patients with type 2 diabetes were recruited for a 3‐month study to examine the health effects of a new dietary fibre, FBCx™.

Differential effects of fatty acids and exercise on body weight regulation and metabolism in female Wistar rats.

High-fat diets made with different fats may have distinct effects on body weight regulation and metabolism. In the present study, the metabolic effects of high-fat (HF) diets made with fish oil, palm oil, and soybean oil were compared with a low-fat diet in female Wistar rats that were either exercised (EX, swimming) or that remained sedentary as controls. Each adult rat was exposed to the same diet that their dams consumed during pregnancy and lactation. When they were 9 weeks old, rats began an EX regimen that lasted for 6 weeks. Twenty-four hours after the last EX bout, rats were sacrificed in a fasted state. It was observed that HF feeding of soybean oil induced more body weight and fat gain, as well as insulin resistance, as indicated by insulin/glucose ratios, than other oils. Female rats fed a HF diet made with fish oil had body weight and insulin sensitivity not different from that observed in low fat fed control rats. For rats fed HF diets made with soybean oil or palm oil, EX also exerted beneficial effects by reducing body fat %, blood insulin, triglyceride and leptin levels, as well as improving insulin sensitivity.

LIPID LOWERING EFFECT OF OMEGA-3 FATTY ACIDS IN GENETICALLY OBESE ZUCKER RATS

Omega-3 fatty acids (n-3 FA) are known to reduce blood lipid levels. Recent data, however, suggested that n-3 FA supplementation may worsen glycemic control in diabetic humans. This study was designed to explore the effects of n-3 FA feeding on lipid metabolism and glycemic control in a strain of genetically obese, hyperlipidemic rats. Lean and obese Zucker rats were fed a semi-purified diet made with either n-3 FA or corn oil (n-6, 10% w/w for both diets). After 16 weeks feeding, lean and obese rats fed the n-3 FA diet showed a significant reduction in blood triglyceride (TG) levels. Obese rats had significantly elevated TG levels in comparison with lean rats. Lean n-3 FA fed rats had elevated lipoprotein lipase activity in adipose tissue while hepatic triglyceride lipase activity was lowered by n-3 FA feeding in both lean and obese rats. Hepatic lipogenic enzyme activities were suppressed by fish oil feeding. However, fish oil feeding significantly increased hepatic gluconeogenic enzyme activity in lean rats. Therefore, n-3 FA feeding may exert different effects on blood lipid and glucose levels in lean and obese subjects.

Short-term weight cycling in aging female rats increases rate of weight gain but not body fat content

OBJECTIVE: To examine the effects of short-term repeated weight cycling (WC) above and below the baseline (BL) body weight (BW) on body weight regulation, feeding efficiency, and fat content in old female Wistar rats when dietary fat content was kept constant.DESIGN: Completely randomized.ANIMALS AND METHODS: Female Wistar rats, 11 months old at the beginning of the study, were randomly divided into six groups (12 per group) after a group of rats (BL) was sacrificed for baseline data collection: the high fat gain (HFG) group gained weight to 20% above the BL weight with a high fat diet (HF) and returned to BL level by food restriction (50% of ad-libitum amount) for five cycles; the high fat loss (HFL) group lost weight to 20% below the BL weight by food restriction (50% of ad-libitum amount) and regained to BL level by ad-libitum feeding for four cycles; the high fat ad-libitum (HFA) and low fat ad-libitum (LFA) groups were fed HF and low fat (LF) diet, respectively, ad-libitum for the entire study; the high fat restricted (HFR group) and low fat restricted rats (LFR group) were fed the HF and LF diet, respectively, in restricted amounts to maintain BW at BL level.RESULTS: A trend of increased rates of weight gain and feeding efficiencies from the first to last cycles for both WC groups was observed, and significant increases was observed between cycles 4 and 5. The rate of weight gain and feeding efficiency of HFL was significantly higher than that of the HFG group for all cycles (P<0.05). The rates of weight loss were significantly decreasing with each successive cycle for HFG, but were unchanged for HFL. Percentage of body fat was not modified permanently from BL to sacrifice for both HFG and HFL groups. The body fat of HFA was higher than that of the other groups (P<0.01), while the body fat of LFA was significantly higher than that of the LFR, BL and HFL groups (P<0.01), but was similar to that of the HFG and HFR groups. The body fat of WC groups and HFR were similar to each other. The percentage of internal fat (retroperitoneal+omental) were similar for the WC groups. The percentage of internal fat of the HFG, HFR and LFA groups were similar, but were significantly higher than that of the BL and LFR groups (P<0.05). The percentage of internal fat of HFA was significantly higher than that of the rest of the groups (P<0.01).CONCLUSION: Short-term WC did not affect body fat content in these animals, but since weight gain became easier and weight loss became more difficult for animals in the HFG group, repeated WC may promote obesity in these rats.

Effects of abuse pattern of gestational toluene exposure on metabolism, feeding and body composition

AIMS Inhalant abuse during pregnancy lowers birth weight and impedes early development. These studies explored the effects of brief, repeated, prenatal toluene exposures in pregnant female rats on body weight, metabolic rate, body composition, and food intake in their offspring. METHOD Rats were exposed to 0, 8000, 12,000, or 16,000 ppm of toluene twice daily for 15 min from gestational days 8 to 20. The effects of such exposures on post-weaning litter weights, oxygen consumption, carbon dioxide output, and body fat content were determined in 2 cohorts (n=23, n=24) of offspring. Food intakes and weight changes in response to 3 different diets (regular chow, purified diet, purified high fat diet) were examined in another cohort (n=24) from postnatal days 72 to 116. RESULTS Litter weights showed a significant linear decrease as a function of toluene dose. Offspring exposed to the 16,000 ppm toluene dose displayed statistically lower energy expenditures than control rats. Male rats exposed to 8000 or 16,000 ppm toluene had significantly greater percentage of body fat as well as total body fat than the other groups. Toluene also significantly suppressed weight gain over the time chow was consumed compared to the 0 ppm control group. Finally there were trends for a main effect of toluene dose on food intake during chow and during high fat diet consumption, with rats in the 12,000 ppm group consuming more than the 0 ppm group on both diets. DISCUSSION These data suggest that, in addition to other previously documented abnormalities in neurological development and behavior, the physiological regulation of metabolism and body composition in males as well as food intake and weight gain in both sexes may be altered by prenatal exposure to toluene.

Nutrient composition: Effects on appetite in monkeys with oral factors held constant

The effects of macronutrients on appetite and total caloric intake in monkeys (Macaca mulatta) was studied using a new feeding and infusion system which yoked intragastric infusion of various nutrients to oral ad lib intake and removed the confounding factor of palatability from the assessment of nutrient effects on feeding behavior. A suction-activated liquid diet feeding system provided free access to a nutritionally complete diet, with 1 ml of diet delivered orally by pump with each discrete suck by the monkey. A second pump was yoked to the oral feeding pump and delivered various nutrients directly into the stomach via an implanted intragastric cannula. Thus, while oral diet composition remained constant, the net diet reaching the stomach varied over ranges of 28 to 77% carbohydrate, 16 to 65% fat and 7 to 36% protein. No significant differences in total caloric intake were observed between intakes of diets with net composition of high carbohydrate or high fat. When protein was increased to 36%, total caloric intake was generally reduced, and this effect was sustained for at least 3 weeks. Therefore, protein appears to have an increased specific satiating effect beyond the caloric content, when compared to carbohydrate or fat.

High-fat feeding of different fats during pregnancy and lactation in rats: Effects on maternal metabolism, pregnancy outcome, milk and tissue fatty acid profiles

This study was designed to examine the effects of consumption of different fats during pregnancy and lactation on maternal metabolism, pregnancy outcome, and milk and tissue fatty acid (FA) profiles. Wistar rats were divided into three groups according to dietary fat source: PM (40% crude palm oil), n = 7; SB (40% soybean oil), n = 7; and VS (40% partially hydrogenated vegetable shortening), n = 8. Rats were fed experimental diets from day 1 of pregnancy to sacrifice, which was one week after weaning of pups (21d). Milk was expressed from dams on day 14 of lactation. PM, SB and VS milk samples had the same fat content and had FA profiles similar to that of their respective diets. SB and VS dams had significantly more pups dead at birth compared to PM dams. One week after weaning of pups, PM dams had significantly higher triglyceride levels compared to all other groups (PM = 2.08 ± 0.27 mmol/L; SB = 0.88 ± 0.10 mmol/L; VS = 0.78 ± 0.08 mmol/L, p<0.05). PM dams may have slower triglyceride clearance, making hypertriglyceridemia apparent post-weaning. Retroperitoneal adipose tissue and carcass FA profiles of dams positively reflected the FA content of the respective diets. Such influence of diet on milk, adipose tissue and carcass FA content may thus alter metabolic processes during and following pregnancy and lactation and may also affect offspring growth and development via differences in milk composition.

Conjugated linoleic acid does not impair fat regain but alters IGF-1 levels in weight-reduced rats

It has been previously reported that in rats undergoing repeated weight gain/loss cycles, more fat is regained than that was lost. Conjugated linoleic acid (CLA), a collective name for a mixture of positional and geometrical isomers of linoleic acid, is known to regulate body composition by decreasing body fat. The present study was designed to examine the effects of CLA on body fat regain in weight-reduced obese rats. Female Wistar rats (n=52), 6 mo old, were divided into 4 groups: 1) HFRF rats (n=10) were fed a high fat diet (40% ww) diet for 9 weeks to an obese state and were then food restricted (50% ad-lib) with a modified high fat diet for 3 weeks to induce a 20% body weight loss. They were then refed the high fat diet ad-lib for 8 weeks; 2) HFCL rats (n=22) were treated in the same manner as rats in HFRF except were refed a high fat diet with 1% CLA (ww); 3) LFCN rats (n=10) were fed regular rodent diet ad-lib; 4) HFCN rats (n=10) were fed a high fat diet ad-lib. Ten HFCL rats were sacrificed after 4 weeks of refeeding while body composition and plasma glucose and insulin assessed for the other groups as a comparison. All remaining rats were sacrificed after 8 weeks of refeeding. After 4 weeks of refeeding, HFCL rats were similar in both body weight and body fat %. At the end of the study, HFCL rats weighed the same as high fat fed rats while HFRF rats weighed the same as rats of the other groups. All high fat fed groups had significantly higher % body fat than low fat fed rats but were not different from each other (HFCL: 22 ± 2%; HFRF: 23 ± 2%; HFCN: 27 ± 2%; LFCN: 15 ± 2%). HFCL and HFCN rats had significantly higher retroperitoneal lipoprotein lipase activity levels than that of HFRF rats (p<0.05). HFRF and HFCL rats had similar plasma insulin, leptin, and estradiol levels at sacrifice. HFCL rats had significantly lower IGF-1 levels (p<0.05) than that of HFRF and HFCN rats, while LFCN rats had levels similar to all groups (nmol/L, HFCL: 10 ± 0.7; HFRF: 13 ± 0.8; HFCN: 13 ± 0.8; LFCN: 11 ± 1.7). We conclude that a 40% high fat diet with 1% CLA fed to weight-reduced obese rats did not prevent the fat regain during the refeeding phase. The previously reported anticarcinogenic effect of CLA reported by other investigators may be partially due to lowered IGF-1 levels without the alteration of other hormone levels.

African American Preschool Children's Physical Activity Levels in Head Start

The purpose of this study was to describe the physical activity levels of urban inner city preschoolers while attending Head Start, the federally funded preschool program for children from low-income families. Participants were 158 African American children. Their physical activity during Head Start days was measured using programmed RT-3 accelerometers. Results revealed that the children spent the most time in sedentary and light physical activity, while their participation in moderate-to-vigorous physical activities was low. Given the sedentary class format and limited physical space for the Head Start programs observed, we suggest adding a structured physical activity component to Head Start schools to fight the overweight and obesity crisis.