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The Diet, Obesity and Genes (Diogenes) study is a pan-European, multicenter, randomized, dietary-intervention study that is designed for assessing the efficacy of moderate-fat diets that vary in protein content and glycemic index for preventing weight regain and obesity-related risk factors after weight loss. The results have shown that a modest increase in protein content and a modest reduction in the glycemic index have led to an improvement in study completion and maintenance of weight loss.

Impaired digestion and/or absorption of dietary protein lowers postprandial plasma amino acid availability and, as such, could reduce the postprandial muscle protein synthetic response in the elderly. We aimed to compare in vivo dietary protein digestion and absorption and the subsequent postprandial muscle protein synthetic response between young and elderly men. Ten elderly (64 [+ or -] 1 y) and 10 young (23 [+ or -] 1 y) healthy males consumed a single bolus of 35 g specifically produced, intrinsically L-[1-[sup.13]C)phenylalanine-labeled micellar casein (CAS) protein. Furthermore, primed continuous infusions with L-[ring-[sup.2][H.sub.5]]phenylalanine, L-[1-[sup.13]C]leucine, and L-[ring-[sup.2][H.sub.2]]tyrosine were applied and blood and muscle tissue samples were collected to assess the appearance rate of dietary protein-derived phenylalanine in the circulation and the subsequent muscle protein fractional synthetic rate over a 6-h postprandial period. Protein ingestion resulted in a rapid increase in exogenous phenylalanine appearance in both the young and elderly men. Total exogenous phenylalanine appearance rates (expressed as area under the curve) were 39 [+ or -] 3 [micro]mol x 6 h x [kg.sup.-1] in the young men and 38 [+ or -] 2 [micro]mol x 6 h x [kg.sup.-1] in the elderly men (P = 0.73). In accordance, splanchnic amino acid extraction did not differ between young (72 [+ or -] 2%) and elderly (73 [+ or -] 1%) volunteers (P = 0.74). Muscle protein synthesis rates, calculated from the oral tracer, were 0.063 [+ or -] 0.006 and 0.054 [+ or -] 0.004%/h in the young and elderly men, respectively, and did not differ between groups (P = 0.27). We conclude that protein digestion and absorption kinetics and the subsequent muscle protein synthetic response following the ingestion of a large bolus of intact CAS are not substantially impaired in healthy, elderly men.

Elevated plasma concentrations of remnant-like particle cholesterol (RLP-C) are atherogenic. However, factors that determine RLP-C are not fully understood. This study evaluates which factors affect RLP-C in the fasting and postprandial state, using multiple regression analyses in a large cohort of lean and obese participants. All participants (n = 740) underwent a test meal challenge containing 95 energy % (en%) fat (energy content 50% of predicted daily resting metabolic rate). Fasting and postprandial concentrations of circulating metabolites were measured over a 3-h period. Obese participants (n = 613) also participated in a 10-wk weight loss program (-2510 kJ/d), being randomized to either a low-fat or a high-fat diet (20-25 vs. 40-45en% fat). Postprandial RLP-C was associated with fasting RLP-C, waist:hip ratio (WHR), [HOMA.sub.IR] (homeostasis model assessment index for insulin resistance) (P < 0.001), and age, independently of BMI and gender [adjusted [R.sup.2] (adj. [R.sup.2]) = 0.70). These factors were also related to fasting RLP-C (P < 0.010), along with gender and physical activity (adj. [R.sup.2] = 0.23). The dietary intervention resulted in significantly lower fasting RLP-C concentrations, independently mediated by weight loss, improvements in [HOMA.sub.IR], and the fat content of the prescribed diet. However, after inclusion of plasma triglyceride (TG), HDL-cholesterol, and FFA concentrations in the models, [HOMA.sub.IR] and WHR no longer significantly predicted fasting RLP-C, although WHR remained a predictor of postprandial RLP-C (P = 0.002). Plasma TG was strongly associated with both fasting and postprandial RLP-C (P < 0.001). In conclusion, plasma RLP-C concentrations are mainly associated with plasma TG concentrations. Interestingly, the high-fat diet was more effective at decreasing fasting RLP-C concentrations in obese participants than the low-fat diet.

In contrast to the effect of nutritional intervention on postexercise muscle protein synthesis, little is known about the potential to modulate protein synthesis during exercise. This study investigates the effect of protein coingestion with carbohydrate on muscle protein synthesis during resistance-type exercise. Ten healthy males were studied in the evening after they consumed a standardized diet throughout the day. Subjects participated in two experiments in which they ingested either carbohydrate or carbohydrate with protein during a 2-h resistance exercise session. Subjects received a bolus of test drink before and every 15 min during exercise, providing 0.15 g * [kg.sup.-1] * [h.sup.-1] carbohydrate with (CHO + PRO) or without (CHO) 0.15 g * [kg.sup.-1] * [h.sup.-1] t protein hydrolysate. Continuous intravenous infusions with L-[ring-[sup.13[C].sub.6]]phenylalanine and L-[ring-[sup.2.[H].sub.2]]tyrosine were applied, and blood and muscle biopsies were collected to assess whole body and muscle protein synthesis rates during exercise. Protein coingestion lowered whole body protein breakdown rates by 8.4 [+ or -] 3.6% (P = 0.066), compared with the ingestion of carbohydrate only, and augmented protein oxidation and synthesis rates by 77 [+ or -] 17 and 33 [+ or -] 3%, respectively (P < 0.01). As a consequence, whole body net protein balance was negative in CHO, whereas a positive net balance was achieved after the CHO + PRO treatment (-4.4 [+ or -] 0.3 vs. 16.3 [+ or -] 0.4 [micro]mol phenylalanine * [kg.sup.-1] * [h.sup.-1], respectively; P < 0.01). In accordance, mixed muscle protein fractional synthetic rate was 49 [+ or -] 22% higher after protein coingestion (0.088 [+ or -] 0.012 and 0.060 [+ or -] 0.004%/h in CHO + PRO vs. CHO treatment, respectively; P < 0.05). We conclude that, even in a fed state, protein coingestion stimulates whole body and muscle protein synthesis rates during resistance-type exercise. nutrition; amino acids; muscle anabolism

The present study was designed to assess the impact of coingestion of various amounts of carbohydrate combined with an ample amount of protein intake on postexercise muscle protein synthesis rates. Ten healthy, fit men (20 [+ or -] 0.3 yr) were randomly assigned to three crossover experiments. After 60 min of resistance exercise, subjects consumed 0.3 g*[kg.sup.-1]*[h.sup.-1] protein hydrolysate with 0, 0.15, or 0.6 g*[kg.sup.-1]*[h.sup.-1] carbohydrate during a 6-h recovery period (PRO, PRO + LCHO, and PRO + HCHO, respectively). Primed, continuous infusions with L-[[ring-.sup.13][C.sub.6]]phenylalanine, L-[[ring-.sup.2][H.sub.2]]tyrosine, and [6,6-[sup.2][H.sub.2]]glucose were applied, and blood and muscle samples were collected to assess whole body protein turnover and glucose kinetics as well as protein fractional synthesis rate (FSR) in the vastus lateralis muscle over 6 h of postexercise recovery. Plasma insulin responses were significantly greater in PRO + HCHO compared with PRO + LCHO and PRO (18.4 [+ or -] 2.9 vs. 3.7 [+ or -] 0.5 and 1.5 [+ or -] 0.2 U*6 [h.sup.1]*[1.sup.-1], respectively, P < 0.001). Plasma glucose rate of appearance ([R.sub.a]) and disappearance (Ra) increased over time in PRO + HCHO and PRO + LCHO, but not in PRO. Plasma glucose [R.sub.a] and [R.sub.d] were substantially greater in PRO + HCHO vs. both PRO and PRO + LCHO (P < 0.01). Whole body protein breakdown, synthesis, and oxidation rates, as well as whole body protein balance, did not differ between experiments. Mixed muscle protein FSR did not differ between treatments and averaged 0.10 [+ or -] 0.01, 0.10 [+ or -] 0.01, and 0.11 [+ or -] 0.01%/h in the PRO, PRO + LCHO, and PRO + HCHO experiments, respectively. In conclusion, coingestion of carbohydrate during recovery does not further stimulate postexercise muscle protein synthesis when ample protein is ingested. resistance exercise; protein metabolism; nutrition; recovery

Fish oil, containing (n-3) PUFA, is associated with a moderate reduction in cardiovascular disease through a multifactorial mechanism involving a decrease in plasma lipids and anticoagulant activity. Two intervention studies on subjects at risk were performed to determine the relation of these 2 fish-oil effects. In study 1,54 overweight subjects consumed 3.1 g (n-3) PUFA daily. In study 2, which involved 42 overweight patients with type 2 diabetes, 20 subjects consumed (n-3) PUFA, whereas 22 others ingested a preparation rich in (n-6) PUFA. Tissue factor-induced thrombin generation (thrombin potential) was determined as an integrated measure of plasma coagulant activity. In both studies, multivariate analysis indicated a strong clustering of fasting concentrations of triacylglycerols, prothrombin, factor V, factor VII, and factor X with one another at baseline. This cluster of factors determined partly the interindividual variation in thrombin generation, of which prothrombin and triacylglycerol concentrations were the main determinants. In both healthy subjects and diabetes patients, high triacylglycerol concentrations (>1.69 mmol/L) at baseline were closely linked to a strong fish oil-induced lowering of triacylglycerol and coagulation factor V, VII, and X concentrations, and thrombin generation. We conclude that high fasting triacylglycerol concentrations predict high procoagulant activity and a lowering of thrombin potential with dietary fish oil.

This study investigates the consequences of inhibition of adipose tissue lipolysis on skeletal muscle substrate use. Ten subjects were studied at rest and during exercise and subsequent recovery under normal, fasting conditions (control trial, CON) and following administration of a nicotinic acid analog (low plasma free fatty acid trial, LFA). Continuous [U-[sup.13]C]palmitate and [6,6-[sup.2][H.sub.2]]glucose infusions were applied to quantify plasma free fatty acid (FFA) and glucose oxidation rates and to estimate intramuscular triacylglycerol (IMTG) and glycogen use. Muscle biopsies were collected to measure 1) fiber type-specific IMTG content; 2) allosteric regulators of hormone-sensitive lipase (HSL), glycogen phosphorylase, and pyruvate dehydrogenase; and 3) the phosphorylation status of HSL at [Ser.sup.563] and [Ser.sup.565]. Administration of a nicotinic acid analog (acipimox) substantially reduced plasma FFA rate of appearance and subsequent plasma FFA concentrations (P < 0.0001). At rest, this substantially reduced plasma FFA oxidation rates, which was compensated by an increase in the estimated IMTG use (P < 0.05). During exercise, the progressive increase in FFA rate of appearance, uptake, and oxidation was prevented in the LFA trial and matched by greater IMTG and glycogen use. Differential phosphorylation of HSL or relief of its allosteric inhibition by long-chain fatty acyl-CoA could not explain the increase in muscle TG use, but there was evidence to support the contention that regulation may reside at the level of the glucose-fatty acid cycle. This study confirms the hypothesis that plasma FFA availability regulates both intramuscular lipid and glycogen use in vivo in humans. muscle metabolism; intramyocellular triacylglycerol; fat oxidation; insulin resistance

Combined ingestion of protein and carbohydrate improves protein balance during ultra-endurance exercise. Am J Physiol Endocrinol Metab 287: E712-E720, 2004. First published May 27, 2004; 10.1152/ajpendo.00543.2003.--The aims of this study were to compare different tracer methods to assess whole body protein turnover during 6 h of prolonged endurance exercise when carbohydrate was ingested throughout the exercise period and to investigate whether addition of protein can improve protein balance. Eight endurance-trained athletes were studied on two different occasions at rest (4 h), during 6 h of exercise at 50% of maximal [O.sub.2] uptake (in sequential order: 2.5 h of cycling, 1 h of running, and 2.5 h of cycling), and during subsequent recovery (4 h). Subjects ingested carbohydrate (CHO trial: 0.7 g CHO*[kg.sup.-1]*[h.sup.-1]) or carbohydrate/ protein beverages (CHO + PRO trial; 0.7 g CHO*[kg.sup.-1]*[h.sup.-1] and 0.25 g PRO x [kg.sup.-1]*[h.sup.-1]) at 30-min intervals during the entire study. Whole body protein metabolism was determined by infusion of L-[[1-.sup.-13]C]leucine, L-[[sup.2][H.sub.5]]phenylalanine, and [[sup.15][N.sub.2]]urea tracers with sampling of blood and expired breath. Leucine oxidation increased from rest to exercise [27 [+ or -] 2.5 vs. 74 [+ or -] 8.8 (CHO) and 85 [+ or -] 9.5 vs. 200 [+ or -] 16.3 mg protein*[kg.sup.-1]*[h.sup.-1] (CHO + PRO), P < 0.05], whereas phenylalanine oxidation and urea production did not increase with exercise. Whole body protein balance during exercise with carbohydrate ingestion was negative (-74 [+ or -] 8.8, -17 [+ or -] 1.1, and -72 [+ or -] 5.7 mg protein*[kg.sup.-1]*[h.sup.-1]) when L-[[1-.sup.13]C]leucine, L-[sup.2][H.sub.5]]phenylalanine, and [[sup.15][N.sub.2]]urea, respectively, were used as tracers. Addition of protein to the carbohydrate drinks resulted in a positive or less-negative protein balance (-32 [+ or -] 16.3, 165 [+ or -] 4.6, and 151 [+ or -] 13.4 mg protein*[kg.sup.-1] x [h.sup.-1]) when L-[[1-.sup.13]C]leucine, L-[[sup.2][H.sub.5]]phenylalanine, and [[sup.15][N.sub.2]]urea, respectively, were used as tracers. We conclude that, even during 6 h of exhaustive exercise in trained athletes using carbohydrate supplements, net protein oxidation does not increase compared with the resting state and/or postexercise recovery. Combined ingestion of protein and carbohydrate improves net protein balance at rest as well as during exercise and postexercise recovery. protein metabolism; dietary supplements: protein intake

Intramuscular triglycerides (IMTG) are assumed to form an important substrate source during prolonged endurance exercise in trained males. This study investigated the effects of endurance exercise and recovery diet on IMTG content in vastus lateralis muscle. Nine male cyclists were provided with a standardized diet for 3 days, after which they performed a 3-h exercise trial at a 55% maximum workload. Before and immediately after exercise and after 24 and 48 h of recovery, magnetic resonance spectroscopy (MRS) was performed to quantitate IMTG content. Muscle biopsies were taken after 48 h of recovery to determine IMTG content by using quantitative fluorescence microscopy. The entire procedure was performed two times; in one trial, a normal diet containing 39% energy (En%) as fat was provided (NF) and in the other a typical carbohydraterich athlete's diet (LF: 24 Eh% fat) was provided. During exercise, IMTG content decreased by 21.4 [+ or -] 3.1%. During recovery, IMTG content increased significantly in the NF trial only, reaching preexercise levels within 48 h. In accord with MRS, fluorescence microscopy showed significantly higher IMTG content in the NF compared with the LF trial, with differences restricted to the type I muscle fibers (2.1 [+ or -] 0.2 vs. 1.4 [+ or -] 0.2% area lipid staining, respectively). In conclusion, IMTG content in the vastus lateralis muscle declines significantly during prolonged endurance exercise in male cyclists. When a normal diet is used, IMTG contents are subsequently repleted within 48 h of postexercise recovery. In contrast, IMTG repletion is impaired substantially when a typical, carbohydrate-rich athlete's diet is used. Data obtained by quantitative fluorescence microscopy correspond well with MRS results, implying that both are valid methods to quantify IMTG content. muscle; nuclear magnetic resonance; [sup.1]H magnetic resonance spectroscopy; oil red O; exercise; intramyocellular lipid; diet

In humans, [beta]-adrenergic stimulation increases energy and fat metabolism. In the case of [[beta].sub.1]-adrenergic stimulation, it is fueled by an increased lipolysis. We examined the effect of [[beta].sub.2]]-adrenergic stimulation, with and without a blocker of lipolysis, on thermogenesis and substrate oxidation. Furthermore, the effect of [[beta].sub.1]- and [[beta].sub.2]-adrenergic stimulation on uncoupling protein 3 (UCP3) mRNA expression was studied. Nine lean males received a 3-h infusion of dobutamine (DOB, [[beta].sub.1]) or salbutamol (SAL, [[beta].sub.2]). Also, we combined SAL with acipimox to block lipolysis (SAL+ACI). Energy and substrate metabolism were measured continuously, blood was sampled every 30 min, and muscle biopsies were taken before and after infusion. Energy expenditure significantly increased -13% in all conditions. Fat oxidation increased 47 [+ or -] 7% in the DOB group and 19 [+ or -] 7% in the SAL group but remained unchanged in the SAL+ACI condition. Glucose oxidation decreased 40 [+ or -] 9% upon DOB, remained unchanged during SAL, and increased 27 + 11% upon SAL+ACI. Plasma free fatty acid (FFA) levels were increased by SAL (57 [+ or -] 11%) and DOB (47 [+ or -] 16%), whereas SAL+ACI caused about fourfold lower FFA levels compared with basal levels. No change in UCP3 was found after DOB or SAL, whereas SAL+ACI downregulated skeletal muscle UCP3 mRNA levels 38 [+ or -] 13%. In conclusion, [[beta].sub.2]-adrenergic stimulation directly increased energy expenditure independently of plasma FFA levels. Furthermore, this is the first study to demonstrate a downregulation of skeletal muscle UCP3 mRNA expression after the lowering of plasma FFA concentrations in humans, despite an increase in energy expenditure upon [[beta].sub.2]-adrenergic stimulation. uncoupling protein 3; thermogenesis; adrenergic receptors; sympathetic nervous system

Iron may induce oxidative damage to the intestinal mucosa by its catalyzing role in the formation of highly reactive hydroxyl radicals. This study aimed to determine iron-induced oxidative damage provoked by a single clinical dosage of ferrous sulfate and to elucidate the antioxidant defense mechanisms in the human small intestine in vivo. A double-lumen perfusion tube was positioned orogastrically into a 40-cm segment of the proximal small intestine in six healthy volunteers (25 [+ or -] 5 yr). The segment was perfused with saline and subsequently with saline containing 80 mg iron as ferrous sulfate at a rate of 10 ml/min. Intestinal fluid samples were collected at 15-min intervals. Thiobarbituric acid reactive substances concentrations as an indicator of lipid peroxidation increased significantly from 0.07 [micro]M (range, 0-0.33 [micro]M) during saline perfusion to 3.35 [micro]M (range, 1.19-7.27 [micro]M) during iron perfusion (P < 0.05). Nonprotein antioxidant capacity increased significantly from 474 [micro]M (range, 162-748 [micro]M) to 1,314 [micro]M (range, 674-1,542 [micro]M) (P < 0.05). These data show that a single dosage of ferrous sulfate induces oxidative damage and the subsequent release of an antioxidant in the small intestine in vivo in healthy volunteers. duodenum; epithelium; lipid peroxidation; small intestine; oxidative stress

The purpose of this review is to examine the relationship between glycemic carbohydrate and its effect on body weight regulation. By contrast to fat, carbohydrate has a positive impact on energy intake, energy expenditure, and body weight control. Despite some debate about the role of the carbohydrate-to-fat ratio in the diet and the prevalence of obesity, metabolic studies show that diets high in fat are more likely to result in body weight gain than diets high in carbohydrate. So far there are no indications that carbohydrate classes differ greatly with respect to energy expenditure and energy balance. However, the impact of carbohydrate source and class, as well as the form in which carbohydrate is consumed (i.e., solid or liquid) on body weight control requires further consideration. Key words: glycemic carbohydrate, body weight regulation

Genome-wide association studies have identified single nucleotide polymorphisms (SNPs) associated with waist circumference (WC) and waist-to-hip ratio (WHR) adjusted for BMI (WCadjBMI and WHRadjBMI), but it remains unclear whether these SNPs relate to change in WCadjBMI or WHRadjBMI with lifestyle intervention for weight loss. We hypothesized that polygenic scores (PS) comprised of 59 SNPs previously associated with central adiposity would predict less of a reduction in WCadjBMI or WHRadjBMI at 8-10 weeks in two lifestyle intervention trials, NUGENOB and DiOGenes, and at 1 year in five lifestyle intervention trials, Look AHEAD, Diabetes Prevention Program, Diabetes Prevention Study, DIETFITS, and PREDIMED-Plus. One-SD higher PS related to a smaller 1-year change in WCadjBMI in the lifestyle intervention arms at year 1 and thus predicted poorer response (β = 0.007; SE = 0.003; P = 0.03) among White participants overall and in White men (β = 0.01; SE = 0.004; P = 0.01). At average weight loss, this amounted to 0.20-0.28 cm per SD. No significant findings emerged in White women or African American men for the 8-10-week outcomes or for WHRadjBMI. Findings were heterogeneous in African American women. These results indicate that polygenic risk estimated from these 59 SNPs relates to change in WCadjBMI with lifestyle intervention, but the effects are small and not of sufficient magnitude to be clinically significant. [ABSTRACT FROM AUTHOR]

Lactoferrin (LF), a glycoprotein present in milk and other secretions, may provide a nutritional ingredient for the treatment of intestinal disorders associated with hyperpermeability, oxidative stress and inflammation. The aim of the study was to determine the survival rate of orally administered recombinant human lactoferrin (rhLF) in the upper gastrointestinal (GI) tract and in the small intestine in vivo in humans. Female ileostomy patients [n = 8; median age 44 (43-57) y] ingested a test beverage containing 5 g rhLF and collected full ileostomy output for 24 h. The passage of the test beverage was monitored using radio-opaque markers. Intact LF in ileal effluent was quantified by ELISA. The entire test beverage passed the small bowel during the 24-h ileal effluent collection period. LF was excreted at a low but constant rate [0.35 (0.28-0.47) [micro]g LF/2 h]. Gastrointestinal passage of the test beverage and LF excretion over time in the ileal effluent were not correlated. In total, a median of 4 [micro]g LF was excreted over the 24-h collection period, whereas 5 g rhLF was ingested. Hence, dietary rhLF is digested in the upper GI tract and does not reach the colon. Intact LF appearing in ileostomy effluent is likely to originate from an endogenous source. KEY WORDS: * lactoferrin * breakdown * digestion * small intestine * ileostomy

Effect of acute exercise on uncoupling protein 3 is a fat metabolism-mediated effect. Am J Physiol Endocrinol Metab 282: E11-E17, 2002.--Human and rodent uncoupling protein (UCP)3 mRNA is upregulated after acute exercise. Moreover, exercise increases plasma levels of free fatty acid (FFA), which are also known to upregulate UCP3. We investigated whether the upregulation of UCP3 after exercise is an effect of exercise per se or an effect of FFA levels or substrate oxidation. Seven healthy untrained men [age: 22.7 [+ or -] 0.6 yr; body mass index: 23.8 [+ or -] 1.0 kg/[m.sup.2]; maximal [O.sub.2] uptake (V[O.sub.2 max]): 3,852 [+ or -] 211 ml/min] exercised at 50% V[O.sub.2 max] for 2 h and then rested for 4 h. Muscle biopsies and blood samples were taken before and immediately after 2 h of exercise and 1 and 4 h in the postexercise period. To modulate plasma FFA levels and fat/glucose oxidation, the experiment was performed two times, one time with glucose ingestion and one time while fasting. UCP3 mRNA and UCP3 protein were determined by RT-competitive PCR and Western blot. In the fasted state, plasma FFA levels significantly increased (P < 0.0001) during exercise (293 [+ or -] 25 vs. 1,050 [+ or -] 127 [micro]mol/l), whereas they were unchanged after glucose ingestion (335 [+ or -] 54 vs. 392 [+ or -] 74 [micro]mol/l). Also, fat oxidation was higher after fasting (P < 0.05), whereas glucose oxidation was higher after glucose ingestion (P < 0.05). In the fasted state, UCP3L mRNA expression was increased significantly (P < 0.05) 4 h after exercise (4.6 [+ or -] 1.2 vs. 9.6 [+ or -] 3.3 amol/[micro]g RNA). This increase in UCP3L mRNA expression was prevented by glucose ingestion. Acute exercise had no effect on UCP3 protein levels. In conclusion, we found that acute exercise had no direct effect on UCP3 mRNA expression. Abolishing the commonly observed increase in plasma FFA levels and/or fatty acid oxidation during and after exercise prevents the upregulation of UCP3 after acute exercise. Therefore, the previously observed increase in UCP3 expression appears to be an effect of prolonged elevation of plasma FFA levels and/or increased fatty acid oxidation. fat oxidation; uncoupling protein; fatty acids; mitochondria

The possibile synchronization of hunger, meal requests and transient blood glucose declines in time-blinded men was investigated by monitoring continuously the blood glucose while and appetite ratings at randomized intervals. Transient blood glucose declines were observed to be associated postprandially with meal requests. Results also showed a correlation between the higher satiating efficiency from high-fat preloads than from simple carbohydrate preloads and the synchronization of intermeal interval and dynamic blood glucose declines.

Research was conducted to test whether the beta-adrenergically mediated thermogenesis in men is altered with aging. Intravenous infusion of nonselective beta-agonist isoprenaline was performed on 11 young and nine older men. The older subjects had higher basal plasma norepinephrine and epinephrine concentrations than the younger men. Results indicate that aging is related to a diminished beta-adrenergically mediated thermogenesis which may generate increased obesity and fat storage caused by a positive energy balance.

Research was conducted to examine the hypothesis that obese subjects are less capable of speedily adjusting fat oxidation to fat intake on a high-fat (HF) diet particularly when exhaustive exercise decreases glycogen stores. Obese subjects were observed after they were switched to an HF diet from a reduced-fat diet to analyze the effect of low glycogen stores on fat oxidation. Results indicate that obese subjects can rapidly adjust fat oxidation to fat intake when exhaustive exercise lowers glycogen stores.