5:2 diet

5:2 diet is working well for me so far, though I'm new to it. I"ve been doing the math and I figure there's no way I can help but lose weight since my average caloric intake (easy to check thanks to myfitnesspal) is less than my metabolic burn rate.

If you're doing 5:2 you do need to watch your calories on the non-fast days, but ONLY to keep at right around your burn rate -- don't try to lose more weight on these days. If you want to go faster than 5:2 you can do the alternate day fast, but in that case you definitely need to keep calorie intake up on your feast days.

There has been recent studies (radio 4 did a programme) including Zoe Halcombe (her reports are on FB) stating that there is no evidence that you lose any more weight than a calorie controlled diet over 7 days. One of the reasons for weight lose may be to the limiting of calories over the 5 days. I did have a go but I felt horrendous, I wasnt able to concentrate on work and had no energy to work out at all. Decided to concentrate on my 1200 calorie diet as set out on here.

"If' by metabolic rate, i sure hope you do not mean BMR. If you only eat your BMR and then only eat 500-600 calories on fast days, I 100% guarantee you that you are under eating and you will be depleting your muscle mass. ... on non fast days, you actually eat above your total daily energy expended. ...

Eating too little will lead to depletion of lean body mass as well as a slower metabolic rate. "

My BMR is about 2400 (I'm a big guy, and still overweight, so I know that will be dropping)

When I was losing weight (successfully) just by calorie restriction I was eating 2100 calories a day at about 1 - 2 lbs a week (generally a bit over 1 lb) so that seemed healthy. I did not add back in my 2 or 3 times a week exercise session, though, so probably on those days I was using more than 2400 calories.

So now that I'm doing 5:2 on normal eating days I'm eating about 2400 calories and on fast days I'm eating 600. By my math before I was eating 14,700 calories a week and now with 5:2 I'm eating 13,200 calories. Not a huge difference there weekly.

But one thing you've got to understand is that the body doesn't have a "caloric intake" memory (except for weight gain) so on fast days I'm losing weight and burning fat but on regular days I'm fully fed. The body doesn't average things out -- it just knows if it has a full load of food/sugar going through the system or if it does not -- and if it does not it starts burning fat (or muscle if it needs to). So with any weight loss program based on calories there's a risk of losing some muscle, but I work out regularly and I don't mind having to build muscle back up if I can just get rid of the massive amount of fat which is hurting my knees and limiting my activities.

I'm not a scientist and I've done no double blind tests on large numbers of people ... but I've got to think that's one of the best points of the 5:2 -- it starves your body and forces it to burn a lot of fat at once and then goes back into normal mode 24 hours later. Whether all the blood chemistry pluses are there or not I don't know, but this summer I'll be getting a full physical and blood workup so I'll have some idea (of course just the weight loss I've gone through will have a big effect).

All I know is ... the perfect diet is just eating enough calories to get by every day and making sure they're healthy calories. And I was doing that before and it worked but the problem is it wears on me and I feel deprived -- not sure if I have a true eating disorder or not but I truly do love to eat. But I think I can make 5:2 work for me, so therefore it IS the healthiest diet for me.

In all I've read about it the concerns of nutritions have NOT been that it's unhealthy or will damage muscle, but that it's unsustainable. And that's a fair concern, but if it works for me to lose weight but I can't sustain it forever (i.e. with 6:1) then I'll find another way to keep the weight off. The only thing for sure -- I've thrown away all my "fat clothes" and I'll not be buying more!