From a recent conversation with a close friend:

Friend: I’ve gotta lose weight – well, at least fat - so I’m going to get at it.

Me: How are you going to do it?

Friend: I’ll have to step up the exercise. Go to the gym more often.  

Me: Science shows little success with using exercise as the main weight loss approach.

Friend: Yeah, I might start running again.

Me: Losing weight really has much more to do with nutrition, though. Maybe we can talk about it.

Friend: My employer has a new program that will pay for a gym membership, and there’s a new one in my neighborhood.

Me: Exercise is extremely beneficial, but for fat loss, it’s all about food.

Friend: Don’t worry, I know how to lose weight. I’ve done it many times. Spin class, maybe Pilates, even Cross Fit. Hot yoga looks cool...

Conventional wisdom is hard to beat. This idea that you can exercise your way to permanent fat loss is embedded in the simple “Calories In, Calories Out” model. "I'll just burn more." It's intuitively appealing and almost impossible to implement successfully.

I ran across this article recently by Julia Belluz and Christophe Haubursin published on January 3, 2018 by Vox entitled "The science is in: exercise won’t help you lose much weight." It’s a good summary, so rather than write one myself, here it is - along with a well-done video below.