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Popularity for Michael Mosley's 5:2 Diet (also known as the Fast Diet) shows no sign of slowing down. If you want to find out more about how to tackle intermittent fasting, and its impact on weight loss and health, read on for Dr Mosley's answers to all your questions.
Is the 5:2 Diet suitable for me? | Is intermittent fasting healthy? | The 5:2 Diet and the menopause | Dealing with hunger pangs | Tackling a plateau | How many calories to eat | When to fast | Does the 5:2 Diet really work?
Diabetics - have more problems controlling their blood sugar levels and need closer supervision.
Vegetarians - the 5:2 Diet works well for vegetarians because they already know the secret of feeling full by filling up on veg.
Q: I wonder how healthy fasting actually is when we are continuously told not to allow blood sugar levels to fall too low and to eat little and often?
A: The idea that you should eat little and often to speed up your metabolism or prevent your blood sugar levels falling is largely a myth. There have been quite a few studies that have shown no difference in metabolic rate between those eating their daily calories split into three meals a day or six. Your body is extremely good at maintaining your blood glucose levels and there should be no problem, unless you are a diabetic. You would need to fast for over 60 hours to have a serious impact on blood sugar levels.
Q: Will my all-knowing metabolism twig what I am up to eventually and slow to a standstill on fast days?
A: As we lose weight our metabolism slows simply because we are carrying less weight around. So you will find weight loss slows, but hopefully not until you reach your desired weight.
"The strangest difference it made to me was that a wart I'd had since I can remember, on my right index finger disappeared! When I spoke to my GP, she explained that it had gone because doing 5:2 had boosted my immune system and kicked the wart into touch!"
"My blood pressure decreased quite dramatically when I started the 5:2 - so much so my doctor repeated the test! I can only assume it was the reason."
Q: Is there any evidence of the effectiveness of this regime with older/post-menospausal women?
A: A number of studies have been done which have included pre- and post-menopausal women and both seem to have done well.
"I have followed this for the last four years, initially to lose the stubborn 21lbs that I had gained around the menopause, and I now maintain my current weight by fasting every Monday."
"I had more or less resigned myself to being a fat old lady, when I saw the Michael Mosley programme about the 5:2 Diet and as a last attempt I decided to try it. To my amazement in four months I was two stone lighter, back to my pre-menopausal weight."
Q: I wake up in the night and am unable to get back to sleep because I am so hungry. Does this suggest that going hungry probably isn't good for me?
A: Try changing your pattern so you have a bigger meal in the evening or put aside a few calories for a glass of milk, which can be filling.
Q: Whenever I restrict my intake, I get so hungry that by dinner time, I would eat anything. Where do you find the willpower?
A: I find the main thing is to have a protein rich breakfast (protein is satiating), lots of fluid during the day and lots of vegetables in the evening with, say, a slice of meat or fish. What you want is bulk and protein; those are the things that keep you full. If you find you can't do 500 calories, try 600.
Q: I am following a low calorie diet of approx 1200 calories a day and although it was fine when I started, it seems to be getting harder rather than easier as I had expected. The plus side is that it has really made me think about what I eat. The minus is that I am permanently ravenous. So part of me now thinks that your diet couldn't be any worse than this - and part of me thinks that if I feel this bad on 1200 calories, how the hell will I cope on 500, even if it is only for 24 hours?
A: Try it and see. A recent study done by Dr Michelle Harvie at Manchester University found that volunteers on a 5:2 Diet, when compared to those on a more typical 1200 calorie a day diet, were more likely to stick to it, lost more weight and had improved biomarkers.
"I no longer have any desire to eat between meals or eat sweets, I have my three meals at regular intervals, feel fuller more quickly and don't eat after eight at night. I too had headaches when I first started, but they soon passed."
"To me a fast day is no different to any other day, except that I skip breakfast and count the calories in my two meals."
"A lot of the recipes are based on lots of veg and can be very filling."
Q: For the last month I have reached a standstill, although I still have some weight to lose. Do you know of any change in regime which could kick start the loss again? This diet has been so easy to follow and I am happy to continue for as long as it takes.
A: Look at the fluids you are drinking on your "feast" days. Fruit juice, smoothies, lattes and booze are all calorie rich and are not satiating.
Q: I have been doing this eating plan for a week and found the fasting days somewhat difficult. However I was fasting for a day and a night. I have read that you can fast for 24 hours, for example from 2pm one day to 2pm the next, which would seem far more manageable...?
A: Try experimenting and see what works for you. We are all different.
Q: Can you please tell me if it is necessary to consume 500 or 600 calories per day and does it have to be on consecutive days to have the maximum effect?
A: The scientific studies are based on men consuming 600 calories and women 500 calories, so that seems a reasonable guideline. Clearly if you find that difficult you can increase, but you won't see so much change. I do it Mondays and Thursdays, but you can choose which days you want - it doesn't matter if it's consecutive or not. On this you should lose around 1lb of fat a week; the apparent weight loss will be more because you will also lose water. Drink loads on fasting days.
Q: As I'm over 60 and reasonably active, is it okay to go over the 500 calories (to 600)? I feel there ought to be some leeway for an older person!
A: You seem to be doing just fine and as long as you are feeling good I wouldn't get pre-occupied by numbers. This is all about finding something practical that works for you.
Q: Why are the number of calories you can eat on the fast day based on gender and not weight? My daughter is only an inch taller than me but weighs considerably more - yet has the same calorie allowance as me rather than the same as her father who is much closer to her in weight and has proportionally less weight to lose.
A: It is just a guide. If you want to eat 600 calories that is fine; weight loss will be slower.
Q: Am I correct in thinking that the researcher you interviewed about intermittent fasting said that ideally one should not eat anything on fast days?
A: Eating calories on fast days is partly because it is easier to sustain, but also partly to keep up levels of nutrients and protein. Protein is not well stored and needs topping up every 24 hours.
Q: I am a bit puzzled about the fast times. I start the fast after supper and, following your guidelines, eat around 500 calories during the following day and end the fast with supper. That means I eat my main meal on both days with snacks in between. It seems to me that isn't much of a fast.
A: Fasting means abstaining from eating for varying lengths of time. I aim for 12-hour stretches, but others find that tougher. Research by Dr Michelle Harvie suggests that reduced calories twice a week, even when spread throughout the day, brings significant health advantages.
Q: As the recommended intake for a woman who is not dieting is 2000 calories, would it be wise to try to stick to this on the days you can 'eat what you like' - assuming if you just stuff yourself with no heed to how much you are taking in the weight will be harder to shift?
A: Yes, better to stick to your normal intake rather than try to stuff yourself.
Q: Is there a 'best way' to space out the two fast days?
A: No, no 'best way'. Whatever suits you. I do Monday and Thursday.
Q: Is it really true that people don't binge on the days when you can eat what they like? I am sure I would be stuffing myself after the abstinence. And then I start wondering how you can possibly lose weight if you are eating - say - a Mars a day 5 days a week.
A: Dr Krista Varady, who has run a number of trials, found that people thought they would binge, but in reality didn't. I certainly find I eat no more than normal on 'feast' days.
"For me this has been the non-diet diet. Although I have two preferred days each week when I do it, I will switch the days around when it is necessary. However you do need to eat sensibly the rest of the week."
Q: Is there really any advantage to any of the fad diets as opposed to just eating more sensibly? The problem for most people in affluent countries is they just eat far too much, and a lot of that is heavily processed food. I believe the recommendation for a woman is 2000 calories a day, so wouldn't it be a better idea to reduce your intake to that, or even a little less?
A: Eating sensibly is clearly a good idea; the problem is that people find restrictive diets hard to stick to. As I mentioned above, a recent study done by Dr Michelle Harvie at Manchester University found that volunteers on a 5:2 diet, when compared to those on a more typical 1200 calorie a day diet, were more likely to stick to it, lost more weight and had improved biomarkers.
"Two years ago I lost two stone on the 5:2 Diet and it remains lost. I was delighted. The weight had all gone on since the menopause and none of my usual methods of losing weight (counting calories and exercising more) seem to work any more."
"I lost a stone easily in the first few weeks and now just maintain the weight I'm at, without having to worry about what I eat or drink on the other five days."
"I've been doing it for about three months, and roped in my husband too. We have both lost about a stone each, and I am very impressed by how easy it is, having previously tried low carb, low GI etc."
"I have battled for years to lose weight and this is the first time I have kept it off. I am a great fan of this way of eating and would encourage trying it."
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