carorees wrote: And your answer to the people who are being strict on feed and fast days and are exercising a lot but not losing weight, despite a BMI of over 25 is...?
My point is that there is a very fine line between "success" (1-1.5 lbs a week), "failure" (0.5 lbs a week) and "doing very well" (2 lbs per week) on 5:2 - It's just a 1.5 lbs equivalent range, roughly 5000 cals. In other words to move from 'failure' to 'success' would be 2500 cals and similarly from "success" to "doing very well". 2500 cals (500 cals/feed day) is not a lot and easily accounted for by variance in activity/eating levels. e.g 3 x plain chocolate digestives or a thirty minute walk or less than 1 mars bar a day?
I think there are a number of tricky issues though:
1) 'Activity' vs 'Exercise'.
I'm basically "sedentary". i.e., at work I now drive a desk with 2 Pcs on top and 2 Pcs underneath. At home I have "my spot" on "my couch". (A couch potato probably moves more than I do). I also hate gardening and DIY. But I have started going to the gym and walking. Whilst my gym sessions are quite intense, I think they may only just offset my fundamentally 'sedentary' life style. This wasn't always the case and prior to becoming a 'desk jockey' I was mostly on my feet all day in an active job (and 5 stone lighter).
Others may not "exercise" but without even knowing it be very "active". i.e. gardening, DIY, ironing, cleaning, playing drums, walking the dog etc etc.
Others may "exercise" and go to the gym but basically be very sedentary. From my own observations in the gym there's issues here. I've just got back from my local gym. I see a lot of folks who seem to avoid breaking into a sweat at all costs, and are for example jogging on the treadmill (but with no gradient) so burning few calories. There's also an issue (which I can't understand) of folks who seem to have an aversion to touching the pulse sensors on any of the cardio kit and appear willing to get into all sorts of funny positions to avoid finding out what there pulse is - so how hard are they working? Then there's those that do cardio and no weights or those that use the gym for networking etc etc.
All these perceptions of "activities" (or lack thereof) can lead to huge variances in "basal metabolic rates" (BMR) [whatever happened to BMR keep seeing TDEE quoted here?] and total calories burnt a day.
2) Calorie Counting.
Measuring the calories accurately in food is difficult (possibly impossible?). e.g Do you use a digital balance always? Do you remember everything you consumed? BUT.. do you believe the labelling on packaging? I don't any longer. e.g. A BK whopper on the US site has more cals than a whopper on the UK site. I guess it could be size, but lately I've started thinking that it could that the labelling laws are different and that this results in the different values in each location. Similarly, there was the recent article on differences in UK/US labelling regarding calories excluded (UK) for fibre whilst these are included (US). All seems somewhat airy fairy to me.
3) The Null hypothesis
Is there a mechanism whereby Net calories gained or lost is not just a function of BMR, calories consumed and activity? Some biochemical pathway as yet undiscovered?
4) A Pragmatic approach
"...your answer to the people who are being strict on feed and fast days and are exercising a lot but not losing weight..."
So... I'm not sure there is a simple answer. The flippant answer is "eat less, exercise more". However, the first place to start would be to initially exclude starvation mode, caloric restriction and do a detailed lifestyle audit to include activity, exercise, food consumed as well as TDEE etc etc.
Personally, as a desk jockey (sedentary) , I found that when on 5:2 I was still eating too much on the '5' days, I've consistently lost weight on the weeks I've tried 4:3 (which for me is therefore better than a plateau, even if its only the same as the Avg for the group as a whole), and increasing levels of activity by walking lunchtimes in work and more formal trips to the gym. These measures have led to me averaging around 1.0lb/week overall. All of which, seems to indicate that for me a major factor is a "sedentary" vs. "active" life style.
So I come back to the idea of a 'Life style audit' as being a possible way forwards for some. The 'sedentary'/'active' life style issue seems key to me.
BW and sorry for length of post.