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The 5:2 Lab

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The findings about the length of time (around 5 years?) after a period of active weight loss for which one needs to maintain a restricted food input is really important, I think. So many of us have succeeded in losing weight and been disheartened by putting it back on so quickly that I think it's probably THE major thing to watch out for when supported people in losing weight. The NHS dietetics team who've been supporting me have a six-month intervention period of monthly 1-2-1 interviews. They have recently, and very helpfully, set up monthly forums that anyone who has had one of the interventions can come along to on a continuing basis, for support. I see that as the most critical period and I'm going to raise it with them at the forum next month. It looks to me as though all the public advice about weight loss needs to re-focus on the factors likely to cause weight-regain and to give help with that, specifically.
I obviously didn't post my observations on the CALERIE paper before leaving ! It was interesting that the LCD group achieved the best weight loss after only 3 months (compared to 6) and kept it off for a further 3 months.

Of course to detect a lasting metabolic change they need to follow up 6 months or more after the intervention ends, which they didn't unfortunately do.

A metabolic slowdown equivalent to a Twix a day is something we ought to be able to cope with :-)
http://www.plosone.org/article/info:doi ... ne.0004377

One of many CALERIE study papers, this one looks at 4 groups - control, CR 25% calorie reduction (less food), CR+EX 25% calorie deficit by 12.5% less food and 12.5% more exercise, and an 890 kcal/day LCD until 15% weight lost, then maintenance. CR and CR+EX continued their regime for the full 6 months.

The LCD group achieved their weight loss within 3 months and then maintained it for a further 3 months. The CR group lost weight faster than the CR+EX group but the latter caught up after 6 months. Both CR and CR+EX were well short of the LCD in weight and fat loss. Actual evidence that LCDs are better than moderate calorie restriction and/or exercise, IMHO.

Image

There was no statistically significant reduction in TDEE in either control or CR+EX groups. CR showed a significant reduction in TDEE of 370 cals at 3 months, beyond that which could be explained by loss of fat and fat-free mass, but this had become insignificant at 6 months and reduced to 200 cals.

LCD group also had a statistically significant reduction in TDEE at 3 months of 500 cals/day but by month 6 (during maintenance for this group only) this had fallen to 275 cals and was no longer significant at the 5% level.

Note that these reductions in TDEE by doubly labelled water include physical activity, thermogenic effect of food etc as well as basal or resting metabolic rate.
Phil, I just saw a post by Mousie who said that she had noticed she lost more weight on weeks that she ate up to TDEE. I have noticed this too. Whether or not due to metabolic slow down or some other reason, it would be useful to know if this is generally true. I was pondering if there is any way to poll folks to find out how many have observed this. It might be just a sub section of people whose bodies work this way or a general rule. I know Dr M tweeted that the big difference between feed and fast days was important but I don't know why he thinks that. Perhaps there is some acute effect of fasting that is reversed if you eat properly the next day.

Anyway, I wondered whether you thought we might be able to get at least some anecdotal reports that it is/isn't important to eat up to TDEE?
carorees wrote: Anyway, I wondered whether you thought we might be able to get at least some anecdotal reports that it is/isn't important to eat up to TDEE?


You could collate some information I guess, but I personally wouldn't put much store by it. I'm the sort of numbers bore that would want to see two groups of 100 single sex subjects one fed TDEE and the other TDEE - 20% for 6 - 8 weeks with regular doubly labelled water tests and respiratory metabolic rate assessments. Ideally the subjects would be in a controlled environment fed measured portions with waste food collected and accounted for etc.

The problem I see is that 2 days at 25% and 5 days at 100% (of a number we can only estimate) is a 21.4% reduction on average. If TDEE was 2000 over 7 days the reduction is less than 1 lb per week and weight fluctuates +/- 2 lbs or more randomly so we're expecting to spot an difference from say -0.6 to -1.0 in something that is randomly between +1 and -3 so IMHO the noise is bigger than the signal. Add to that the self reporting of intake and exercise etc.

Having said that it may carry more weight than Dr Mosley's n=1 experiment.

Did Varady's 6/7 calorie restriction plus 1/7 fast tell us anything, compared to her ad-lib plus fasting work ? The one that compared food and liquid diets.
Oh yes, I'd forgotten that! Worth checking.

Of course, the reason(s) for (perhaps) losing more weight when not restricting calories on feed days, could be to do with a psychological effect regarding reporting of food intake on feed days or exercise motivation or a lower intake on fast days if you are well fed the day before or something.

Mind you, if it occurs the reason would be less important to most people than the fact that it exists.
quick look at two studies :

1. 8 weeks of calorie restricted eating 6 days a week 880-1000 cals, virtual fast on 7th day (120 calories of juice drink). Weight loss 3 kg.

2. 8 weeks of ADF 125% / 25% of calories. Weight loss 4.8kg.

1. reported a 29% calorie restriction, 2. should be 25% so on the face of it the ADF does better by losing more with a smaller restriction.
Interesting and perhaps supporting the notion that restricting on feed days is not helpful. Although it is probably not statistically significant, could one say that restricting calories on feed days does not appear to improve weight loss even though one could not be sure that eating up to TDEE or a bit over would increase weight loss? A subtle distinction but potentially important for us when offering advice to those who are struggling...
Watching these forums over the past several weeks I see some patterns:

1. People who restrict calories on feed days tend to complain more about stalled weight loss.

2. People who feed a little bit throughout the day on fast days don't seem to be as satisfied with their ADF experience as people who eat little or nothing for the greater part of about 20 hours and break their fast with a light evening meal.

I'm thinking it might be the cycling of ADF that works in some way beyond the aspects of 5:2 being psychologically sustainable ("I only need to make it to tomorrow and I can eat whatever I want!"). That is, highs and lows, up and down, makes sure your body doesn't get used to the reduced calorie intake that's happening in a way that isn't true for straightforward calorie restriction every single day (and even every single hour).

To take it to the opposite extreme, what if you were to set your daily calorie intake at exactly 1800kcal and you made sure that at the top of every even-numbered hour you ate exactly 150kcal, even to the point of setting your alarm and waking up 3 or 4 times during your night to do so? My guess is that the body would get used to this and would adjust its metabolism in a way that minimizes TDEE and weight loss.

That other article on autophagy seems to support this idea. Maybe making sure you eat more on feed days (without going overboard, of course) would increase the benefits of this WOE?
Currently I would say there is no evidence that restricting calories on a fast day is detrimental.

The metabolic rate measurements in Heilbronn's 2005 ADF paper don't point to a significant difference in energy expenditure on fast vs fed days and they were told it would be a good idea to eat twice as much as normal on feed days.

6292 ± 268 6329 ± 260 were the kJ/day numbers for a feed day and a fast day, guess which was which :-)

Faced with that, I don't see how we could say that eating a lot on feed days was going to "rev up the metabolism" or any other bovine scatology.

I would say that newcomers should do what they normally do on feed days and maximum 500-600 calories on fast days. I'll have a harder look at the papers to see if I can tease out relevant comparisons.
just to add we probably should differentiate <25, 25-30 and >30 BMI people too, as the ability of fat reserves to fuel the body is variously reported to be about 30 kcal/day per lb of fat tissue. In order to fuel a 720 cal deficit needs 24 lbs of fat reserves which a 120 lb (8st8, 54.5kg) woman at 20% fat would have but a bigger deficit would be a challenge.
Just going to pour some petrol on the embers of this debate and show you a wee spreadsheet I created:
http://dl.dropbox.com/u/32116230/52fast ... ories.xlsx
I averaged the calorie intake over the days between each weigh in and plotted this against the change in weight since the last weigh in.

Due to the poor precision (and accuracy) of my bathroom scales, the weight changes are crude but the graph shows a couple of points that might be of interest.
1) going over an average of around 2000 cals per day coincided with a weight increase
2) going below an average of around 1500 cals per day coincided with a weight increase
3) increasing daily calories after a drop coincided with a spike of weight loss


OK, so its a sample of 1 but I wonder if it might suggest some directions for us to investigate. One is the influence of mixing things up over a longer timeframe than single days (i.e. feast/famine on a larger scale).

Any other nerdy types interested in doing the same exercise?
missing week ? at about day 106
Yes, I was away that weekend so no weigh in.
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