I have a 29-year plot of my body weight, ages 54-82, including 4 diets and 3 periods of regaining weight. I have no conclusions to offer you other than a weak conclusion, "It helps to weigh yourself often". Once I purchased a balance beam scale, but I found that my weight fluctuates a pound or more from day to day for no apparent reason, this despite weighing myself mornings only before drinking. (Rising earlier gives higher weights. Rising time seems to vary more in old age.)
As to why everyone is fatter these days, I think it is because nowadays food tastes better because the world has now been combed over successfully for delicious food.
My 1992 diet began from common concern or for long-forgotten reasons. The 2004 diet began from the beer-drinking example of Bill Curry who touted the Atkins diet and quickly proved it worked. The 2015 diet was triggered by a knee injury---torn meniscus. I feared to lose my mobility! It was annoying that while sitting on a lawn I would have difficulty rising to stand. This weight drop was really easy. Simply eat at mealtime only, and eat nothing any other time. Soon afterward I moved into a retirement home where meals are supplied and we are generally overfed. Folklore among the women here is that one's arrival automatically adds 15 lbs. As you see I almost plateaued instead. The 2019 diet was motivated by my wish to be able to continue bicycling until I have a serious fall. I must thank my 10-mile Stanford commute (with battery assist bike) and Henry Lew's bicycling club.
This year I drove my weight below the 2004 low which means it is now below the 1992 measurements when this record begins. This photo proves I was fat already in 1989 (age 51). As for previous records, my diary tells me I weighted 181 in 1964.
Now that I've begun sipping the 170s, should I set a deeper goal? My only real goal is to prevent a reversal.
Below from 1992 to 2020 with a high of 244 and a low of 178