I have a 31-year plot of my body weight, ages 54-85, including 4 diets and 3 periods of regaining weight. The first conclusion I have to offer you is that "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.
In 2019 I drove my weight below the 2004 low which means it became 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.
Below from 1992 to 2023 with a high of 244 and a low of 175
For my friends, I really should cook up a list of those habits that I chose to change. At first, I resolved to stop eating any free food at work. That was amazing. I lost a pound a week for months! Then of course the gains begin to taper off. I don't remember all the steps on the journey, but I will not forget a big one. When food sits front of me, I will eat it no matter what. This created a crisis. When I moved to a retirement home, we didn't prepare our food, we selected it from a menu and waited for a server to bring it. The meals were too big. I needed to figure out how to control this problem. I did. (1) Bring along a plastic box to carry away excess food. (2) Learn to throw away leftovers. Covid helped out. I no longer go to the dining room. I carry my meal home so I need not dwell at a table and wait for service.
Since New Year 2021, the days that I popped above 180 I was annoyed. I installed horizontal lines across the page to make this more clear. I'd try to eliminate all beer, wine, ice cream, chocolate, and peanuts. If I succeeded, within a few days, I'd be back below and could resume occasional alcohol and small servings of ice cream. Then I caught myself snacking a little. Sometimes a tiny dish of peanuts, sometimes a beer after biking, sometimes a couple of triscuits. Mostly, I should limit my snacking only to when my wife snacks. We see that in late 2020 I had achieved a couple years of stability but, they are gradually, very gradually drifting upward.
During 2021 I see an upward drift from predominantly below 180 to predominantly above 180. Now in April 2022 I have resolved again to take no between-meal snacks (that my wife has not invited me to take.) Come back in 2023 to see if I've been able to drop deeply into the 170s. To do this I have not simply "made a resolution". I have altered my daily logging process. In the morning I weigh myself and write down the weight on a nearby sheet. Before bedtime I now begin placing place a small "-" after the weight if I have taken ZERO snacks that evening. Should I relapse, my transient paper list will show a record of it that is hard to ignore.
If I ever get to 168, my BMI will drop from "overweight" to "normal". Shall I set 168 as a goal? Not yet. My real goal is remaining consistently below 180.