I have been above 200 and under 160 at least 5 times in my life. Takes a few years to pack on the extra weight then I buckle down and loose it again. I am sure it is playing hell on my body but if I didn't fluctuate I would probably be 400+ pounds by now. Going to try to make this one my final drop but in the last two months I have packed on another 15 pounds, most of it since getting hurt.
One thing I will say is try to live clean. Pay attention to what you eat. Every single time I eat fast food I gain weight, feel like shit and get angry because the cravings are so strong for crap food. It is also about timing, don't eat within 3 hours of sleeping. Avoid eating and then sitting down to "let the food digest". If I am eating a meal I will generally go for a walk pretty quick after, nothing crazy maybe 30 minutes at a snail's pace.
I have a pretty good routine for loosing weight. My wife is down 90+ pounds herself since she started. Her goal is to loose 1/2 her body weight, like me she has already lost 1/3+ of her weight.