Please don t give me the run-around, be straight with me. Thank you for your consideration. Research would suggest that your metabolism is not permanently lowered by your dieting. However, yo-yo or cyclical dieting can affect body composition. Frequent dieting followed by regaining weight can result in a decrease in muscle mass and an increase in percentage of body fat.
Body composition does affect energy use.
Those with more muscle mass require more energy than others weighing the same amount but having a higher body-fat level. This would help with ongoing weight management.