The FastDay Forum

@ADFnFuel

ADFnFuel wrote that the 'site-wide wisdom' as he so eloquently phrased it, is that you lose approx 0.5 kg a week with 5/2. This is correct if you restrict your calories to 500/600 twice a week and calculate the calorie deficit. However, I have a thyroid problem (thyroid stopped working altogether) and therefore was put on synthetic thyroid hormone. Apparently the dosage was far too low, because I gained 4 kg in ten days whilst eating normally. I then immediately reinstated the 5/2 regime and upped the dosage of my thyrax. This was later authorised by my internist I hasten to add, it's not something you should do without medical supervision. The point I'm trying to make is that my weight loss of 1 kg a week can in part be ascribed to 5/2 but also to my thyrax, which undoubtedly increased my BMR, which obviously in turn helps the weight loss. The reason I explain this so extensively is to prevent other fasters from becoming disappointed - 0.5 kg/week is the average and there are weeks without any weight loss at all. The thing is to persevere notwithstanding. All the best to my fellow fasters.

Actually, truth be told, my phrasing was more an indication of laziness to avoid looking up the original thread that discussed expectations and probable outcomes.

Interesting, from a quick search, that fasting isn't necessarily contra-indicated for thyroid issues.

It is possible, with a bit of experience, to increase one's weight loss rate if desired. For example, moving to 4:3 - Monday, Wednesday, Friday instead of the more common Monday, Wednesday 5:2 fast days adds just one day but can have a noticeable effect. ADF adds another 1/2 day per week but also eliminates schedule flexibility. (For reference, my own ADF-based rate was over 2 kg per week for several months. Roscoe's loss rate was up there too; feel free however to discount both since we are male.)

Another simple step is to completely skip that 500 calorie evening meal. Very convenient because there's no calorie counting required, nor meal prep or clean up either. BTW, that "25% of daily calories" number was originally included in 5:2 as an astute psychological tactic to ease first timers into the seemingly abrupt and radically contrarian idea of fasting (gasp!).

I believe that the upper limit to a possible weight loss rate is one's BMR divided by the number of calories in a pound - roughly 6/10th of a pound (1.3kg) per day with a full, liquid-only fast - no calories consumed at all. The body has no choice but to utilize body fat given this scenario. But then what's the rush? There's are many other considerations that lead to a permanent solution.