OBJECTIVE: To investigate the long-term effects of changes in dietary carbohydrateafat ratio and simple vs complex carbohydrates. DESIGN: Randomized controlled multicentre trial (CARMEN), in which subjects were allocated for 6 months either to a seasonal control group (no intervention) or to one of three experimental groups: a control diet group (dietary intervention typical of the average national intake); a low-fat high simple carbohydrate group; or a low-fat high complex carbohydrate group. SUBJECTS: Three hundred and ninety eight moderately obese adults. MEASUREMENTS: The change in body weight was the primary outcome; changes in body composition and blood lipids were secondary outcomes. RESULTS: Body weight loss in the low-fat high simple carbohydrate and low-fat high complex carbohydrate groups was 0.9 kg (P`0.05) and 1.8 kg (P`0.001), while the control diet and seasonal control groups gained weight (0.8 and 0.1 kg, NS). Fat mass changed by 7 1.3 kg (P`0.01), 7 1.8 kg (P`0.001) and 0.6 kg (NS) in the low-fat high simple carbohydrate, low-fat high complex carbohydrate and control diet groups, respectively. Changes in blood lipids did not differ signi®cantly between the dietary treatment groups. CONCLUSION: Our ®ndings suggest that reduction of fat intake results in a modest but signi®cant reduction in body weight and body fatness. The concomitant increase in either simple or complex carbohydrates did not indicate signi®cant differences in weight change. No adverse effects on blood lipids were observed. These ®ndings underline the importance of this dietary change and its potential impact on the public health implications of obesity.

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SERÉ S, LUIS, JORDI LOPEZ-AYERBE, RAMÓ N COLL, ORIOL RODRIGUEZ, JUAN VILA, XAVIER FORMIGUERA, ANTONIO ALASTRUE, MIGUEL RULL, AND VICENTE VALLE. Increased exercise capacity after surgically induced weight loss in morbid obesity. Obesity. 2006;14:273-279. Objective: To investigate the effects of surgically induced weight loss on exercise capacity in patients with morbid obesity (MO). Research Methods and Procedures:A prospective 1-year follow-up study was carried out, with patients being their own controls. A symptom-limited cardiopulmonary exercise stress test was performed in 31 MO patients (BMI Ͼ 40 kg/m 2 ) before and 1 year after undergoing bariatric surgery. Results: At 1 year after surgery, weight was reduced from 146 Ϯ 33 to 95 Ϯ 19 kg (p Ͻ 0.001), and BMI went from 51 Ϯ 4 to 33 Ϯ 6 kg/m 2 (p Ͻ 0.001). After weight loss, obese patients performed each workload with lower oxygen consumption, heart rate, systolic arterial pressure, and ventilatory volume (p Ͻ 0.001). This reduced energy expenditure allowed them to increase the duration of their effort test from 13.8 Ϯ 3.8 to 21 Ϯ 4.2 minutes (p Ͻ 0.001). Upon finishing the exercise, MO patients before surgery were able to reach only 83% of their age-predicted maximal heart rate, and their respiratory exchange ratio was 0.87 Ϯ 0.06. After weight loss, those values were 90% and 1 Ϯ 0.08, respectively (p Ͻ 0.01). When we compared the peak O 2 pulse corrected by fat free mass before and after surgery, no significant differences between the groups were found. Discussion: After surgically induced weight loss, MO patients markedly improved their exercise capacity. This is due to the fact that they were able to perform the external work with lower energy expenditure and also to increase cardiovascular stress, optimizing the use of cardiac reserve. There were no differences in cardiac function before and after surgery.