Wearing the same size pants, when I wear pants when I was 18. I am so fortunate.
I have fluctuated 10 lbs since my freshman year in college. I was 130 during high school, used weight lifting to get to 165 my freshman year and now at age 57 I weigh 172.
I have no formal education but I have been an ardent student of health, exercise and wellness, my wife has worked for a chiropractor where we both learned a lot, I have hired sports trainers, gone to human performance labs, worked with nutritionists, did an Ironman at age 40 and am now doing CrossFit knocking on 60 years old. And I am able to be near the top of the leader board competing against college students.
I may not have that formal education but I'm living proof that what I know works.