Questions from a possible newbie

[IsawJimmykissingSantaClaus]

If anyone could answer my questions I would be very grateful. I am really interested in giving this WOE a go. I watched the Horizon documentary again yesterday (watched it originally, can't remember when that was!) and it made great sense. I have read bits and bobs on mumsnet/other sites which have not seemed (to me) to match what was said in the documentary.

1. The female scientist on the programme studied 2 sets of people who did a 5:2 diet. One group ate low fat on their eating days and the other high fat. There was NO difference in their results. So it didn't matter what you ate on the eating days. She also stated that binging tended not to occur. But on Mumsnet and other 5:2 websites, the usual healthy eating is suggested on the eating days. So is that just because it's hard to shake off the healthy eating advice we've followed so far or is it the only way to have effective weightloss? The documentary was essentially about preventing disease risk and early aging. Weightloss was a by product. I want to do this mainly for weightloss at the start.

2. On a thread about why this WOE doesn't work for everyone, some posters said that they doubled their usual amount of calories on eating days (forgive me if this is the wrong terminology), therefore cancelling out any calorie loss from the fasting days. And that is why they claimed not to lose weight. But on the programme they clearly stated that the benefits of fasting outweighed those from consistent calorie reduction. Something to do with the shock of fasting on your body. So my question is has the 5:2 diet been hijacked and turned into something it doesn't need to be (with TDEEs/healthy eating/drink your water/exercise)?

I am not cynical about 5:2. I really want to do it. It's just that it sounded so simple on the documentary and it sounds pretty complicated on the internet.

Hi, I just started this two weeks ago, but have done quite a bit of research on it because I had concerns, like you do.

1. while the documentary showed researcher Krista Varaday having a hamburger with Michael Mosely, she has since clarified that the 'high fat' group in her study ate healthy high fat food. Low carb diets, for example, would tend to be higher fat. From a nutrition point of view healthy food is important, but nothing is forbidden with this WOE. So if you want something low on nutrients on a non-fast day, have it. It won't interfere with the benefits of fasting, but the healthier your diet the better. There is more to health than fasting, such as minerals, vitamins and fibre. That is my understanding at least.

2. Varaday said people usually ate 10% above TDEE on their fast day. If you are one of the few who eat enough to cancel out the deficit of the day before then it probably won't help you lose weight. As far as I can tell, counting TDEE is mostly recommended for people like me, with a lot to lose and issues around food, or people trying to shift those difficult last few pounds.

That's just my take on it. I'm sure the other more seasoned fasters will be able to refine that a lot more. It might also be worth checking out the official 5:2 Fast Day website. They have a TDEE calculator so I'm sure they explain the reasoning behind it there.

I love it already. I've lost seven pounds in 12 days, and I was calorie restricting before so it's not all water weight. Best of luck whatever you chose to do

First, distinguish between fasting for health and fasting for weight loss:
Intermittent fasting seems to have health benefits. However, weight loss nearly always requires a weekly calorie deficit, around 3000 cals for 1lb
(the exceptions are those for whom fasting corrects a metabolic problem or removes a trigger food / sensitivity)

If you check Mosely's Fast Diet site, he also recommends aiming for TDEE on NFDs. Our link in the OP on the main thread is to his TDEE calculator.

His site came long after the Horizon program and his advice there built on the experience of what happened when ordinary people did 5:2.
He, Mimi Spencer and the Horizon test subjects naturally ate about TDEE on NFDs, so that was their natural eating. He started with a BMI of 26, Mimi only BMI 21, so not overweight.
However, most folk coming to the 5:2 threads are overweight and got that way by eating much more than TDEE. So, unlike Michael and Mimi, on NFDs some folk eat back some / all of their calorie deficit and lose very slowly or soon plateau.

Many, many folk on these threads have lost weight on 5:2, but often by following Mosely's updated advice for ordinary overweight people, rather than what was ok for Horizon media folk or volunteer test subjects.

Some folk here naturally eat about TDEE and never need to count, so 5:2 is really simple for them (they probably don't post much) Others need to learn to eat only this amount.
Also, if you lose say a stone, your TDEE reduces, so you need to slightly reduce food again, unless you exercise more / retain muscle.

Mosely recommends exercise, as we do. In fact, he brought out the Fast Exercise book as a 5:2 companion.

5:2 works with whatever kind of food you like: Mediteranean / low carb / low fat / vegan / ....
We recommend cutting down on junk and alcohol, because scientific studies show too junk damages health over the longterm and also slows down weight loss. Again, Mosely didn't do junk and Mimi's new book for 5:2 bootcamp is based on cleaner eating.

So, the Horizon program outlined the broad theory. Our threads and Mosely's site detail the real world application.

Varady developed ADF / Every Other Day diet, which has FDs every other day. She hasn't researched 5:2

ADF has more FDs, hence a higher weekly calorie deficit and also some people find their stomach shrinks. Varady says people lose on ADF if they eat up to 125% of TDEE, so most people don't need to count NFD cals.

These answers are fantastic and exactly what I needed. Thank you ALL so much. I will check out the links/books mentioned. You have really made it much clearer for me

Christina 7lbs in 12 days is amazing. Congratulations!

Well I am starting my 4th week! I am surprised at how easy the fast days are. I thought I would be a gibbering wreck. I have been overeating on the NFDs but only because it's Christmas. That is over now. The first week I saw good weight loss and hope to get that again now all the goodies have gone!! I curse my height though. Despite rounding up an inch and starting running again, I can still only have 423 cals on a FD.

Well done, the FDs probably stopped you from gaining over Christmas-New Year.
Now, to start losing properly, you need to aim for TDEE on your NFDs.
I recommend you mfp until you are used to correct portion size for this.
Plenty of support too on the main thread 48.

Thank you BigChoc. I am really trying to stick to my TDEE now Christmas is over. I have been checking the other threads out. Really enthused about this WOE.