I also often eat only one meal per day, have never been overweight, have always (until recently) been extremely active, and as I near my 50th year I am still not carrying around a lot of extra fat.

Once in awhile, maybe every month or two, I'll go three or four days with absolutely no food but plenty of water.

I've been in better physical condition, but my doctors are happy with my current BMI.

That said, I've always felt better when I ate less food more often.