"What has been the most effective strategy for you in achieving your weight loss goals?"

Following a specific diet plan - Vegetarian since 1974, was slim, got fat, got obese, stayed obese, got slim again, stayed slim . . . eating the same range of foods, pretty much same meal timing, still vegetarian.

Increasing physical activity and exercise - Went from sedentary blob to athlete in my late 40s, at that point began training regularly and fairly intensely 6 days most weeks, even competing (not always unsuccessfully in age-group competitions) . . . stayed obese for another dozen years.

Incorporating more whole foods into my diet - Been mostly a whole-foods, hippie-dippy whole grains, lotsa veggies/fruit eater since at least my late teens. It was pretty easy to eat too many calories worth of that stuff, too - it tastes good, and I'm a hedonist. I'm not saying I never ate treats or junk food, but it was much less than the average USian, and the majority of my eating was whole foods. Lots of whole foods. Too much.

Seeking support from friends or a community - The Community here is great and I've learned a lot from it, but you asked about "most effective for weight loss". That part was not absolutely essential for me, more like a helpful adjunct. In my real (non-MFP) life, I avoided telling other people that I was pursuing weight loss. (Most of the conversations with people in real life are dysfunctional, IME.) Friends/community were much more important to me in becoming and remaining athletically active, and that's still true now. But like I said, I was very active and stayed fat/obese. My exercise didn't change much while I was losing weight - mostly I just kept doing what I'd been doing for years. I'm still doing that, almost 8 years into maintenance, though my total exercise volume increased a bit during the pandemic because I had more time for it.

What does that leave? Calorie counting. That was key for me, the most effective thing, hands down.

I do think overall good nutrition is important, so do have macro goals and try to be near them, but that's nutrition/health, not weight loss.

But that's just me. I don't think it's universal. I don't think much of anything about weight management tactics is universal. I think what we can get from other people is ideas to consider and experiment with, not definitions of what absolutely will work for us because it worked for others.