ABSTRACT
Overweight or obesity becomes a worldwide public health issue; the global obesity pandemic. Strategies to effectively prevent overweight and obesity are needed. Slow eating, which involves chewing food slowly and thoroughly, can be an effective strategy to prevent overweight and obesity. Previous studies reported a relationship between rapid eating and overweight. Candidate factors inducing the relationship have been thought to be related to increases in appetite and energy intake through rapid eating, allowing the ingestion of a greater-than-optimal volume of food. While the counter effect of slow eating has been widely known, effects of eating speed on digestion, absorption, and metabolism has yet to be elucidated. If eating speed affects digestion, absorption, and metabolism, eating speed can be a factor explaining the relationship between eating speed and body composition. The present review is to summarize the effects of eating speed on digestion, absorption, and metabolism, consequently suggesting preferable effects of slowly eating on increasing energy expenditure after eating.
ABSTRACT
A study was conducted to investigate the effect of exercise intensity on the recovery of autonomic nervous activity after exercise. Ten subjects performed four kinds of 10-min cycle exercise with target heart rates of 100, 120, 140, and 160 beats/min (THR 100, THR 120, THR 140 and THR 160, respectively) following 5 min of exercise to increase the heart rate to the target level. The beat-by-beat variability of the R-R interval was recorded throughout the experiment including the 5-min pre-exercise control period and the 30-min recovery period. Spectral analysis (fast Fourier transform) was applied to every 5-min R-R interval data set before, during ( 5-10 min) and after exercise at the target heart rate. The low- (0.05-0, 15 Hz : P<SUB>1</SUB>) and high- (0, 15-1.0 Hz : P<SUB>h</SUB>) frequency areas were calculated to evaluate sympathetic (SNS) and parasympathetic (PNS) nervous activities as P<SUB>1</SUB>/P<SUB>h</SUB>and P<SUB>h</SUB>, respectively. During exercise, SNS of THR 160 was significantly higher, and PNS of THR 140 and THR 160 was significantly lower than the respective pre-exercise values (p<0.05) . Althouglt all indicators recovered to, or overshot the pre-exercise values at 20-30 min after THR 100 and THR 120, heart rate and SNS were still higher and PNS was still lower than the pre-exercise value after THR 160. These results suggest that the recovery of cardiac autonomic nervous activity is slower after high-intensity exercise than after low-intensity exercise, and that the recovery of autonomic nervous activity after acute exercise does not always corrrespond linearly on the exercise intensity.