Any diet that means you take in less energy than your body needs will lead to weight loss. Eating a less than healthy diet doesn't bother me in the short term as its no worse than eating a higher calorie poor diet and carrying around extra weight too!
The question for me therefore has to be, what are we capable of sticking to and what best makes use of our strengths and allows us to retrain our weaknesses to allow us to lose the weight and rehabilitates us to change what got us fat in the first place so we don't regain.
For me, being able in my mind to pig out on my non fasting days would have done nothing to retrain my expectations and get me into learning about portion sizes. It also would not have given the advantages that the Cambridge steps had for me in gradually introducing new foods and thus being able to identify the effects these had on my body and (most critically in the long term) the mind.
There will always be people who think they know what's best for you when they haven't got a clue what your issues are or how best to prompt you to change them. At the end of the day, you need to identify your strengths and weaknesses where food is concerned (i really recommend doing a thought diary to chart thoughts and feelings where food is concerned) and then work out what approach would best suit your needs.
If it were just about doing a diet, rather than mostly being about mind and attitude, then there wouldn't be so many overweight and obese people who are unable to lose weight in the longterm.
I successfully lost 95lbs last summer and have kept it off and not needed to diet since. Those who were so bloody prescriptive in telling me how wrong I was have never once seen fit to say they might have been wrong. They really upset me at the time and if I'd let them them affect me I wouldn't have lost my weight, and most importantly I wouldn't have learnt how to maintain that weight loss without yoyo dieting.