kencc wrote: With your graph, I'm not sure of the relevance of comparing mid-night to mid-night calendar days when mid-night doesn't coincide with any calorie intake event or the start/end of a calorie deficit period.
Thanks for the graphs, I did one on an hourly basis which got even more involved. Your variant with a bigger lunch and a cut back on the second dinner in particular.
I use midnight for a number of reasons, one being that it doesn't have much risk of clashing with a meal and getting embroiled in a "which day does this belong to" debate.
Secondly all of the clinical trials (which underwrite the concept of ADF and modified ADF) use calendar days, typically having no calorie intake after 22:00 sometimes earlier.
Thirdly their are circadian rhythms of leptin, thyroid hormones etc so "different things" are likely to happen overnight.
Fourthly at midnight people are usually in bed. So those are my reasons for considering a day as a diurnal / calendar day and not a sliding 24h window.
I'm also aware that some (not you) seem to take a 24 hour reduction as meaning a normal lunch followed by a normal lunch the following day (possibly an hour later) with 500-600 calories for dinner & breakfast. That runs the risk of having a much reduced deficit if (unlike you) lunch is the main meal of the day.
I agree that over a week you achieve the calorie reduction. So does someone cutting a percentage off every meal - continuous calorie control. However, as we know that continuous calorie reduction does not achieve some of the metabolic improvements, but ADF does, then we need to ensure that what we do or recommend is as close to the ADF protocol or modified ADF as tested as possible.
Of course if one is simply interested in calorie reduction then any changes anytime that add up to a weekly, monthly or annual deficit are fine.
The question is in my mind is their any evidence
that two calendar days at 1,000 calories is a sufficient reduction to deliver the results that attract people to the 5:2 plan, especially the "health" benefits other than simple weight loss and things like retention of Fat Free Mass that is seen with a high restriction of calories but not with a moderate one.