Both, plus being lucky enough to be in the right mental state. I have lost notable amounts several times in my life. The only times I lost good amounts without "deliberately trying" were once at university and when I lived in Taiwan. They were from a combo of near daily (1 1/2 hour +) long distance walking and/or dancing, not always having access to food
(& low appetite), being very busy and/or being hypo/manic, and sometimes suffering from major gastro problems, an issue I've had off and on throughout my life. The other times, I did watch my eating in some way (no/little counting WW Core plan or low carb with counting, plus exercise. I kept the weight off for a long while after by maintaining those lifestyles, even w/o counting. I was usually the thinnest in my immediate family, even despite bipolar medications and genes from a family of overweight or even obese people. I am now almost as heavy as I was once 15 years ago, when severely depressed for months and on a weight unfriendly mix, but I see that as sadly normal for my family, plus the last three years have been very stressful! No exaggeration. I do need to lose weight because diabetes type 2 is knocking at my door. My sister, mother, a grandmother, great grandmother, and some cousins contracted it. Others were borderline.

What do you enjoy doing on a rainy day?