The FastDay Forum

Good morning fellow fasters,

recently I read an answer from @carorees about how no weightloss after a year of 5:2 could be due to the body only emptying its glycogen stores during the fastdays and not getting to tap into the fat stores. This completely resonated with me and I was wondering if it could help to empty/lighten the glycogen stores through exercise either on the evening before the fastday, or on the morning of the fastday itself?

thank you for all your help already, de_vi

(who apologises to be such a passive reader here but I mostly follow the forum during the day while at work through RSS feed in my Outlook inbox - and the browser we have at work is so old it does not support even the login so I can hear everything you say - but not post, pathetic, isn't it? So posting this from home just now and look forward to reading your replies during the day... )

Welcome di_vi. Glad you could post. I don't know the answer to your question, but I wanted to say hello. I am in this situation.

As in the other thread, you're both working to lose weight from what is already considered a normal BMI. The closer we get to our bodies "happy point", the more difficult it becomes to lose additional weight.

Energetic exercise (a 10K+ long run, weight lifting, HIIT), will help reduced glycogen stores (which typical average around 2,000 calories). Combining it with carb restriction (<50g) would be even better.

Moving from 5:2 to 4:3 (~500 cal per week) or ADF (~1000 cal) will also effectively reduce total intake requiring very little effort.

Consider each of these as personal experiments. Log what you decide to try for at least 1-2 weeks to discover what works best for you.

As long as the average daily energy balance is in a deficit over a certain period of time, you will burn fat mass. You can eat a pound of sugar every day and still burn body fat as long as you burn off sufficient calories.

There is little reason for casual trainees/dieters to even think about glycogen store depletion. It's something that even professional bodybuilders don't always do, cause its beneficial effects are questionable and usually require considerable planning and care.

Our body will always utilize its fat stores for energy to a certain extent. Yes, glycogen availability matters, but it's not all there is to it.

You can burn body fat quite easily even with regularly near-filled glycogen stores.

I mean, I sometimes eat up to 500 grams of sugars a day. Heck, probably even more. I don't think I've ever managed to deplete my glycogen reserves completely. Hasn't stopped me from burning off enough body fat to step on a bodybuilding stage.


There are some special dieting protocols like Lyle McDonalds Ultimate Diet 2.0 that are based on very complex scientific concepts to maximise fat loss through glycogen depletion and refilling, but I've heard that it's an Extremely difficult diet to follow and isn't recommended for casual trainees.

All in all, I wouldn't worry about glycogen depletion. It's enough to create a small average energy deficit over a period of time and that excess fat will burn off.