The FastDay Forum

"Sustainability" seems to be a key selling point for "The Fast Diet"/5:2. Just wondered, is there a formal definition of "sustainability" for Diets/WOE/WOL? If not, and if you wanted to measure it, what would you measure?

"Sustainability" seems to be a key selling point for "The Fast Diet"/5:2. Just wondered, is there a formal definition of "sustainability" for Diets/WOE/WOL? If not, and if you wanted to measure it, what would you measure?

I think it's a euphemism for compliance. Many/most diets work for weight loss but people tend to abandon them. Their reasons for non-compliance may vary, but if most people find it too difficult to comply with a diet's rules for more than a few months, it's not sustainable.

That's what I'd measure, anyway.

Hi Ubizmo,

"euphemism for compliance"

Agreed. I also wondered about the "more than a few months" approach. Perhaps 'percentage of those enrolled who achieve target'?

In the Australian radio interview Dr M mentioned that the big fallout from the fast diet happens in the first four weeks, and people who stick through that period tend to stay with it.

This makes sense intuitively to me, because (a) the first four weeks are the hardest, (b) a lot of people 'have a go' without intending to continue and (c) a proportion of people have unrealistic expectations that the weight will just fall off magically (i.e. not realising that this diet works by calorie restriction like other diets), and are discouraged when the 'magic' fails.

Looking at our forum's tracker data, the mean dieting period for people on the tracker is 4 weeks 5 days, and the 'User Data Per Week' chart suggests that there is a steady tail-off in data for the first 8 weeks and the decline is much slower after that. But of course the tracker data is itself quite new (the forum is only 8 weeks old after all.)

I would suggest that the real acid test of sustainability is what proportion, out of those who follow a given diet for 3 months, have substantially maintained (or increased) their weight loss after a prolonged period - say 1 year.

It will be a while before we know whether that can be said of the fast diet, but this forum might be able to help answer the question in due course.

[carorees]

Having read quite a bit about weight regain after dieting recently it seems that the longer you can maintain your weight after weight loss the better the chance of keeping it off but that if at any time you go back to your former eating patterns it is highly likely the weight will be regained so on a personal level, sustainability means that the new WOL can be continued for life. Having said that, I found in the stuff I read that if the weight loss is maintained for around 5 years, that is a good indication that it will stay off. So perhaps we have to wait 5 years before we know! But I'll go with Dominic's suggestion of 1 year for now!

It's interesting, I have read in healthcare discussions that it takes 21 days for a change to become a habit and 6 months before it becomes part of your "personality". I guess that may explain why some people fall off the wagon as it were around the 4 week mark.