The FastDay Forum

I know I already started a thread about the 5:2 diet a couple days ago, but I have some questions about Alternate day fasting should I choose to try that method. In my first thread I said I'd start 5:2 soon, but maybe I'll consider ADF depending on the answers to these questions.

1. I've heard that for ADF, for it to be true fasting you eat NOTHING every other day. Would ADF also work if I just restrict myself to 500 calories every other day instead of eating nothing at all if I like that better?

2. Also, if I do make it a true fast and eat NOTHING every other day, do I still have to follow the rule on the non-fast days to not go over my TDEE, or can I just eat however much I want since the next day I'll eat nothing?

3. Can I switch to 5:2 anytime after starting ADF if I find its not for me?

4. If I do choose to go with ADF until I've reached my goal weight (I only want to lose about 30 pounds), can I then if I choose switch to 5:2 to maintain my weight?

5. If I do go with true fasting, how long will it take my body to get used to eating nothing every other day? Once my body is used to it, will I then no longer feel hungry on those days?

1. you can definitely have 500 calories on "fast" days when doing ADF. This is what all of Krista Varady's research is based on. It is sometimes referred to in the literature as mADF (m for modified, to indicate that it's not a true fast).

2. There really is no rule in either 5:2 or ADF that says you can't go over your TDEE on non-fast days. Some people add this rule when they plateau. The original diet in both cases says eat what you want on non-fast days. In Krista Varady's studies, most people don't end up overeating by much on non-fast days - 110% TDEE on average if I remember correctly. Why this happens is not completely understood, but there are some hypotheses about stomach shrinkage and/or changes in appetite. I would recommend, at least in the beginning, to not count calories so carefully on non-fast days. If you're worried about mindlessly overeating, maybe keep a food journal. Otherwise I would say, eat healthy food when you are hungry. Most people here find they are not ravenously hungry after fasting.

3. of course! Some people who try ADF or 4:3 find that they like the rhythm of it, and don't like 5:2 because it's longer between fast days. But I'm sure others have made a successful switch.

4. Again, of course. Krista Varady has people switch from ADF to a maintenance plan that involves eating 1000 calories on fast days rather than 500. But plenty of people here just reduced the number of fast days. Once you get to maintenance, you'll probably have to play around a bit to find what suits you and what works for you.

5. I'll leave this to other people to answer since I've never tried it!

1. MaryAnn pretty much nailed it. The research Krista Varady did on ADF was on 500cal Fast days and no restrictions on Feed Days. She found that 500cal was a sweet spot between losing weight quickly and maintaining muscle mass. People who ate 1/2 of their TDEE (approx. 1000cal) on fast days lost weight slowly while maintaining muscle mass. People who ate nothing on fast days tended to lose weight quickly but the weight loss included muscle mass which is not helpful long term. People on 500cal fast days got the best of both worlds: faster weight loss than 1000cal and minimal muscle loss.

2. On ADF you can eat normally as much food as you want on feast days. As MaryAnn stated the research shows that people don't eat 2x the calories on feed days. They simply can't physically eat 2 days worth of calories in one day. They still end up with a calorie deficit for the week which results in weight loss.

3. Yes you can switch between the 2. Others here have tried one or the other and found it wasn't for them but found another form of intermittent fasting that worked for them.

4. There are a variety of maintenance strategies once you get to your goal weight. Check out the maintenance threads for ideas. Those who have succeeded can best advise.

5. Krista Varady's research shows that it takes about 2 weeks for ADF participants to experience reduced hunger on fast days. I tried ADF for about 2 weeks and it took me less for my physical hunger to subside. It took me maybe a week. I couldn't keep ADF up for social reasons, but I didn't find it so hard in regards to hunger. But then I find with 5:2 there is a similar result. I'm not so hungry on either fast or feast days once I get in the rhythm. I'm more fighting emotional/boredom hunger than true physical hunger.

Since I'm drawn to ADF but 5:2 suites my lifestyle, I actually do a modified 4:3 type of pattern with Monday, Wednesday and Friday as fast days, with Friday's evening meal as a regular, no-calorie-limit meal. I don't normally fast on weekends unless I'm on my own at home, so weekends and Tues and Thur are feed days. The same every week. Others fit in their fast days as their schedule allows. There are quite a few permutation on intermittent fasting. You might want to start out on the one that fits your personal schedule best. You can switch things up if it's not working for you for whatever reason.

Thank you guys for the helpful replies!

@Thatgirl come on over to the DODO (day on day off) tent, that's where us ADFrs hang out and can help you get into the DODO groove if that's the way you're heading x

@Thatgirlpleased to hear you're thinking of ADF. Basically you can tailor fasting to suit your own personal setup/preferences. I tried 4:3 last week but got sidetracked so I think I'll return to ADF next week. You don't really ever go without food on a fast day (unless you want to) . No, Fast days = 500 cals (600 if you're lucky enough to be a man )
For me, ADF gives me the fasting security I need. 5:2 leaves me too exposed to temptation.
Good luck and look forward to seeing you over in the ADF/DODO tent
xx