The present study showed that the effects of high-fat and high-carbohydrate evening meals persist at least overnight and suggests that knowledge of recent dietary history is essential to the effective design of metabolic studies.

BACKGROUND: Ghrelin, a 28 amino-acid peptide secreted primarily from the stomach has been identified as the endogenous ligand for the growth hormone secretagogue receptor. Ghrelin is suppressed in the postprandial state and has been linked to both type II diabetes and obesity. AIMS: To investigate the effects of a period of overfeeding with high-fat dietary supplements on plasma ghrelin levels in nonobese men. METHODS: Six healthy males (21-34 y; BMI 21-24 kg/m 2 ) underwent the dietary intervention after completing diet and exercise diaries for 7 days. For 3 further weeks subjects followed their own diet diary supplemented with 125 ml single cream and 50 g roasted peanuts (88 g fat, 15 g Protein, 8 g carbohydrate) every day. Oral fat tolerance tests (OFTT) were undertaken at baseline, 7, 14 and 21 days of fat supplementation. The diet was increased in energy by 3.9 MJ/day and from a mean of 29-45% energy intake from fat with a small weight gain noted each week (P ¼ 0.009). RESULTS: Ghrelin concentrations were significantly reduced during the baseline OFTT. The postprandial ghrelin response (AUC) was significantly reduced following 2 weeks of dietary supplementation (P ¼ 0.005) increasing the suppression of plasma ghrelin by 18% despite only a 3% increase in body weight. Plasma triacylglycerol (P ¼ 0.009) and leptin (P ¼ 0.035) concentrations were also elevated and postprandial pancreatic polypeptide levels decreased (P ¼ 0.038) following dietary-supplementation. CONCLUSIONS: These results suggest that the metabolic profile associated with obesity, including a reduction in plasma ghrelin levels, may be related to recent dietary energy intake and precedes the development of significant adiposity.

The heart rate response of 59 patients aged 17-79 years implanted with seven different types of rate responsive pacemakers was evaluated during graded exercise treadmill testing and during standardised daily activities. The heart rate response in patients with pacemakers was compared with the chronotropic response in 20 healthy controls of similar age and sex distribution who performed identical protocols. All pacemaker types adequately simulated the control heart rate response during the graded exercise treadmill test except during the early stages of exercise. However, during everyday activities, the response of ventricular rate responsive (VVIR) Most previous studies to assess sensor driven rate responsive pacemakers used treadmill testing or bicycle ergometry.'l'8 We compared heart rate changes in patients with single and dual chamber rate responsive pacemakers with the chronotropic response in a group of healthy controls during various standardised everyday activities and during graded exercise treadmill tests. Patients and methods PATIENTSFifty nine patients aged 17-79 years (mean 57-9, 35 (590o) men) had seven types of rate responsive pacemaker implanted. Ventricular rate responsive pacemakers (VVIR) were implanted in 33 patients. They were the activity sensing Siemens Sensolog I (10), minute ventilation sensing Telectronics Meta (8), activity sensing Medtronic Activitrax (8), and QT sensing Vitatron Tx II (7). None of these patients had the signs or symptoms of the pacemaker syndrome."' Dual chamber rate responsive systems were implanted in 26 patients. Six had Medico Phymos VDD systems, which require a single lead with free floating atrial bipolar sensing and unipolar ventricular sensing and pacing; 10 had DDD systems; and 10 had activity sensing DDDR systems. The table shows the indications for implantation.All patients were followed up at 6 weeks and 3 months after pacemaker implantation and were optimally programmed to the rate response mode according to the manufacturers' instructions.We studied heart rate responses in a group of 20 apparently healthy people aged 23-76 years (mean 55 0, 12 (60%) men) during standardised daily activities and treadmill testing.