I haven’t seen the research on which Dr. Michael Mosely based his report for the BBC Horizon programme. Most of the research that specifically backs intermittent fasting was carried out by the National Institute on Aging (NIA) in Baltimore. Most of what I can find on their website refers back to research into the effects on calorie restriction in mice.
I want to know more and I’ll be writing about what I find in the coming weeks. In the mean time I’d promised something about main meals and the 5:2 diet.
The theory, as laid out by Dr. Mosely, is that if you restrict your calorie intake to 600 kCal per day as a man, or 500 per day as a woman, your body stops growing and starts repairing itself. He says that research by the NIA suggests that the benefits of intermittent fasting can be had by restricting your calorie intake for two, non-consecutive, days each week.
My approach has been to eat as much as possible within that 600 calorie limit to try to reduce the feelings of hunger.
So far the best way I’ve found of doing this is to cut out carbohydrates entirely on fasting days. Carbohydrates are calorie heavy.
Conversely, if you’re fasting, vegetables are your friends. You can eat piles of veg and still clock up a fairly modest number of calories.
Most vegetables provide between 18 and 30 kCal per 100g. In very broad terms you can have about 600g of veg and it’ll only be 150 kCal or, if you’re having two 300kCal meals a day, half your allowance for one meal. I tend to try to eat one veg-heavy meal each fasting day.
The option pictured here is really simple; It’s a 175g piece of swordfish cooked with no oil in a griddle pan, skin and fat removed. That’s about 220 kCal. I’ve added 250g of steamed broccoli (about 80 kCal) and a small pepper, again griddled without fat. That’s another 20g. Together with a little tobasco and tomato ketchup and low fat yoghurt I reckon it’ll total around 350 Kcal, which so long as your other meal is a little more modest it should be well within the guidelines. It should be pointed out that swordfish is rather more calorific than a white fish like cod, but it makes a nice change.
Another of my typical main meals combines a bowl full of low calorie coleslaw with fish. I simply chop red cabbage, grate some carrots and add a little raw onion, mix in a spoon of low fat yoghurt will add 10-20 kCal, some Tabasco and a tin of sardines in tomato sauce (around 140 kCal).
A third regular option is two quorn sausages (around 70kCal each), a poached egg (another 70 kCal) and steamed broccoli.
It’s not necessarily the sort of food that I would gravitate towards left to my own devices. Actually, freed from the disciplines of intermittent fasting, I’d probably eat far too much toast or biscuits. Indeed I’ve demolished about a dozen biscuits this afternoon. So the discipline is actually forcing me to eat well. And you know what? I actually feel way better for eating far more raw food than ever before.
I don’t want to overstate the benefits. I didn’t have my IGF-1 levels tested before I started and I have no idea what they are now, but prior to Christmas I’d shed 6kg in the previous three months or so. To put that in context I weighed around 78kg when I began this regime and weighed around 72kg ± ½kg after 12-14 weeks. My ideal weight based on my height and the BMI scale would be around 70kg. So I hadn’t vast excesses of weight to shift.
However weight loss isn’t the main end for me. It’s the supposed wider health benefits from restricting your calorie intake.
It’s mainly those wider health benefits about which I want to question the NIA. I’ll be writing quite extensively about their answers when I get them.