Have you tried it? I did, it's easier only for some time. After you lose about 6-7% of your body weight it's very hard to eat less, your whole behaviour changes.
Dropped 25kg (45ish lb) 3 years ago. Gained 12kg back the next 2 years which I removed during the last 6 months. Still more weight to shed but I know what works for me and what kind of effort it requires: going hungry by eating less.
Like lot of fat-logic people I used to think that exercising was required and even the only thing needed to get fit. "I'll just start exercising and be back to an healthy weight" is just a fantasy. There is no miracle way of doing it.
Had a friend take notice, so he took it up himself. Dropped the best part of 60lbs (27kg) over the course of the year. Very different diet, but again tracked everything he ate (again, often to the gram) and lifted weights instead of walking. He was baffled with how simple it ended up being, but was pleased with himself nonetheless.
There are absolutely people who are successful at losing (and maintaining) more than that, but they are a pretty small minority.
I don't have sources in front of me, but this is based on many conversations with my sister-in-law, who is just wrapping up her dietetics internship (after completing her undergrad in nutrition). I'm sure I can get some sources from her later in the day if you would be interested.
For some reason unbeknownst to me, exercise makes eating less a lot easier.