[energy123]

Ask anyone who has been obese and subsequently lost weight and they'll tell you the same thing. Eating less is both a sufficient and necessary condition to losing weight. Exercise is neither sufficient nor necessary because the caloric surplus these people are on significantly exceeds the amount that you can practically burn through exercise. While you're right that exercise can help on the margin, it's just not a useful intervention that moves the needle much as far as weight loss goes.

[ch4s3]

I don't know why anyone here has the idea that I'm arguing that exercise alone is key for weight loss. I have very clearly only claimed that all else equal increasing exertion will lead to a calorie deficit.

> While you're right that exercise can help on the margin, it's just not a useful intervention that moves the needle much as far as weight loss goes.

There's more to exercise than just the thermodynamic effects of calorie expenditure. Building muscle and/or cardiovascular capacity will improve your quality of life and will complement any weight loss. You can improve your mental health by becoming more physically active, and this is well established. Those mental health gains and physical health improvements make it easier to maintain a better diet. Beyond the marginal, but significant calorie expenditures you can create a positive feedback loop.

[timrichard]

Yup, can confirm - for me, at least.

At one stage, I started walking home from work at my fastest pace. 5 miles, 5 days a week. No other lifestyle changes. No significant weight loss.

A few years later, I started tracking calories with myfitnesspal and keeping to a limit (1600 initially, 1400 when it became easier). No exercise, but steady and impressive weight loss. I seem to have kept most of it off. I think a lot of it becomes psychological - not being afraid to feel appetite or skip meals if already satiated from earlier.