It might matter to mood, but it doesn't matter in terms of weight gain/loss.

You could eat nothing but 1000 calories of pure sugar a day and still lose weight

> You could eat nothing but 1000 calories of pure sugar a day and still lose weight

Yes, if you were locked in a room and passed exactly 1000 calories of sugar cubes and water every single day. Most of us live in the real world with food all around us, easily available, and responsibilities to stay on top of. It's really easy to say "this diet is making me feel terrible, I'm just going to eat what I want so I won't be so cranky to my kids".

And likewise you could take a knife and cut out belly fat. It is possible. However it has significant negatives that make it unlikely that people will follow through with the idea. I totally agree that if a person is successful at eating only 1000 calories of sugar per day then they will lose weight. But they wont be successful.

You know that's a completely irrelevant comparison. There is nothing causing a person to gain back weight after losing it outside of willpower.

http://www.cnn.com/2010/HEALTH/11/08/twinkie.diet.professor/

Now if only you could put willpower in a bottle.

Calorie restriction diets feel like holding your breath for 6 months straight. Then as soon as you can't take it anymore, you exhale and instantly gain it all back. It's horrible. Nobody's will can hold out for that long.

Some people are happy eating whatever diet keeps them at an ideal weight. Some people never will be, and it's a form of torture.

And yet it works. I know because I've done it and lost a TON of weight simply by not eating.

If the goal is to "solve the obesity epidemic", it doesn't matter if it works for a small number of people. The reality we must wake up to is that calls for people to eat less will never, ever be successful at solving the problem.

Willpower, hunger, and habit.