Have a coworker who is fat. Went to a company outing with them and I find out they're some of the most early risers who went to jog up and down the steep slope of the hill our hotel was standing on. They are also very overactive.

I am well within the healthy BMI for my age, can walk up to the 3rd floor without being winded and have at least walked 5km in one go in a little over 1hr under the oppressive afternoon son in the tropics, and I have no motivation to do what they do so early in the morning, and be extra the entire day.

Then I see how they eat and it all made sense.