The FastDay Forum

[carorees]

I have spent today number crunching the results from the questionnaire we sent out ages ago which you have been so patient about waiting for the findings!

I have just done some very simple statistics comparing those who had experienced a fast weightloss with those with slow weightloss.

I sorted the data according to rate of weightloss and divided the group into 5ths (quintiles). I took the top quintile and compared their questionnaire answers with those in the bottom quintile using some very basic statistics. The average weightloss per week in the top quintile was 0.97kg compared with 0.14kg in the bottom quintile.

The results are rather interesting, though more sophisticated analysis might throw some of the findings out.

The things that show a statistically significant difference between the big losers and the little losers are as follows:

• Time on diet (7 weeks for quick losers vs 16 weeks for slow losers)
• Starting BMI (31 vs 26)
• TDEE at baseline (2994 vs 2561) (this was calculated by me from the data on activities supplied by the respondents using a website that allows different activities to be entered. The values it comes up with are rather high I think, but for the comparison this is not so important I think)
• Having dieted in the last 6 months (4 vs 12 respondents)
• Having only dinner on a fast day (14 vs 6 respondents)
• Duration of complete fast over 20 hours (13 vs 2 respondents)
• Change in feast day habits: less snacks, less sugary food, less carbs, more vegetables, fewer ready meals and a trend towards less alcohol.
• Time spent sleeping/lying in bed (mean 7.29 hours vs 7.9 hours)

Many of the above are unsurprising, such as time on diet, starting BMI, TDEE at baseline, but some of the others could be worth looking into.

There were also some things that were slightly surprisingly not significantly different between the two groups, most notably, the number of people with a medical condition that might slow weight loss (i.e., hypothyroid, PCOS or fibromyalgia).

Anyway, here is a link to a table of the results, for the scientists to pull apart and tell me what I did wrong! If anyone is able to do some more sophisticated analyses on the data for me, do let me know as what I have done is certainly not good enough to say we know for sure what factors can help to speed up the weightloss. What I would really like to do is to correct for the time on diet and starting BMI.

Thanks Caroline. That does look interesting. I don't know whether the results indicate clear cause and effect (stats make my eyes glaze) but I'd quite like to experiment with the following factors to see if they help with weight loss -

Having only dinner on a fast day (14 vs 6 respondents)
Duration of complete fast over 20 hours (13 vs 2 respondents)
Change in feast day habits: less snacks, less sugary food, less carbs, more vegetables, fewer ready meals and a trend towards less alcohol.

[carorees]

Yes, I think that it is a good idea to try those things, but, of course the "study" has many flaws, most especially the feast day habits as we don't know how much snacking, carbs, sugar, veggies and alcohol people were having before they started 5:2.

One of the most interesting results is the one meal a day and length of fast (basically the same thing of course) in the big losers group. I think it is interesting because the big losers had been following the diet for less time yet I get the impression that most people start by having 2 or 3 masks on their fast days, so I might have expected there to be less of a difference between the two groups in fasting hours than we actually see.

Also, I think that the longer total fast together with less snacking on feast days might be important. I think that longer gaps between food in general gives the body a chance to lower insulin levels thereby allowing fat burning to occur.

I'm still hoping a stats wizard will come forward and offer to do a better analysis!

Finding it slightly odd no one else has picked up on this yet - seems to me to be really interesting info. It's getting buried under the weight of the other posts, I reckon!

Had another look at the table - the categories of NEAT and Fast Day Exercise are interesting just for being so inconclusive. I still believe exercise helps my weight loss (I know this isn't true for others here). I take it there wasn't a separate question for general levels of exercise?

[Moogie]

Thanks for this Caroline interesting results indeed!

[carorees]

Finding it slightly odd no one else has picked up on this yet - seems to me to be really interesting info. It's getting buried under the weight of the other posts, I reckon!

Had another look at the table - the categories of NEAT and Fast Day Exercise are interesting just for being so inconclusive. I still believe exercise helps my weight loss (I know this isn't true for others here). I take it there wasn't a separate question for general levels of exercise?

There were questions about exercise, which were used to calculate TDEE, so I can look at those separately. I'll do that and let you know...can't believe I didn't think of doing that already!

Thanks Caroline, that's really interesting.
Sorry I can't help with the stats.

@shachat although nobody else has commented, there have been more than 200 views and several have thanked carorees, so at least the info is being looked at.

The highlighted points fit perfectly with my initial assessment of the best way to do 5:2 - one meal, 23 hrs fast, no snacking and healthy eating with minimal sugar and grains. Could not see the point of spreading calories over 2 or 3 small meals.

I exercised on fast days also.

It worked for me, so these findings must be right!

I am of the same view as I eat just one meal on a fast day and generally exercise early the following morning. However, I have to say that if I had started that way I am not sure that I would have managed to stay on 5:2 as long as I have. It was only by initially having three meals, then two and finally one that I ended up in this fantastic place that I am.
It is really interesting that all this data is being collated and I hope that the stats will start to back up what we know from experience.

[carorees]

OK, so I had a quick look at the exercise issue and found that the amount of minutes spent doing various levels of exercise per day was not significantly different between the groups. Interestingly, though, what was significantly different was the amount of time spent sleeping/lying in bed resting. The big losers group only spent 40 minutes less in bed on average (7.29 hours vs 7.9 hours) but statistically this was a significant difference.

The quality of the sleep did not seem to matter, but just the time spent in bed. At first glance this is slightly at odds with the scientific literature which found that poor quality/shorter sleep was associated with obesity, but perhaps it is a reflection of the higher starting BMI in the big losers group.

Whatever the reason, it might suggest that once you're awake you'd be better off getting up and about than lying in bed resting!!

I have updated the table with the extra results.

Thanks for that, Caroline. Was rather hoping for a finding on exercise that would back up my theory (that exercise helps weight loss), so a bit disappointed, but I shall carry on flying defiantly in the face of scientific evidence.

I knows what I knows!

[carorees]

Perhaps the exercise that people are doing is helping them all equally hence no statistical difference between the big losers and the little losers! Remember that these simple stats can only suggest possible areas to look at and are in no way proof that any particular action will help/hinder weightloss in an individual.

Thank you so much for crunching the numbers. (I am in awe of those who can whip statistics into shape. I am missing that gene and the organization gene.)
Although I am one of those who does not usually wait for the evening meal to break my fast, I think it would probably be very effective. As for the exercise, I think it is vital for me--probably equal parts motivation and core strengthening which is also motivational.

Thanks from me too, I'm afraid numbers aren't my thing either. Distilled info is interesting.

Exercise certainly helps (me) with well-being. If I exercise I feel better, if I feel better I could fast more easily. But surely exercise builds/tones muscle which in turn means more calories required to keep the body ticking over?

Caroline - just back from my holiday and this is interesting reading indeed. Thank you for all your work on this.