A UK TV programme (Monday 6th August 2012) generated much interest about Calorie Restriction and Intermittent Fasting. The programme was a Horizon documentary, by Michael Mosley, called “Eat, Fast and Live Longer” (The comma is very important!)
I did a review of the programme, so you’ll be able to see what it was about by reading this – it will be long gone from iplayer. This free download will also explain the difference between Calorie Restriction (CR) and Intermittent Fasting (IF) and the three things that can vary within IF options.
The document also asks and answers – what has been proven by research into Intermittent Fasting? Has it been proven to make humans live longer? (No) Has it been proven to reduce the human risk of Alzheimer’s? (No) And so on.
Michael Mosley tried a number of options for the programme – a four day fast (if a cup-a-soup doesn’t count!); alternate day fasting and fasting two days a week. He simply found the latter option – two days a week – more bearable than the other options and thus “The Fast Diet” was born and 5:2 became a familiar term in UK dieting speak.
One of the people interviewed in the programme was Dr Krista Varady. She had been researching alternate day fasting for some time, which Mosley tried and rejected in favour of starving for fewer days each week.
In PR interviews for the book this week, two very interesting comments were made by Varady:
1) On BBC Breakfast, on January 14th 2014, at approximately 1 min 40 secs in, Suzanna Reid mentions “the 5:2 diet” and asks Varady “You were involved in the research for that diet?” To which Varady replies: “There’s actually not any research on 5:2 itself, so all of the research quoted in that book is actually on every other day dieting. So when they talk about all the cholesterol lowering effects and weight loss effects, they’re actually reporting fasting every other day and not two days a week.”
2) On Woman’s Hour, on January 15th 2014, just after 23 mins in, Jane Garvey asks some brilliant questions. Here’s how the conversation goes:
Garvey: “You were part of that Horizon programme, all about fasting. So, outline what you believe, are the benefits of fasting.”
Varady: “It involves something called a feast day, where people can basically eat whatever they like, alternated with something we call a diet day, where people would eat about 500 calories, as either a lunch or a dinner. I’ve run about 10 years of studies involving 5-600 people, so we’ve looked at a lot of aspects … the heart protective and diabetes protective effects…”
Garvey: “Hang on – heart protective? diabetes protective? How and why?”
Varady: “After about four weeks or so this diet helps to lower cholesterol levels, triglyceride levels, blood pressure, blood sugar levels, insulin…”
Garvey: “How does it do that?”
Varady: “How does it do it? It’s basically the weight loss.”
Garvey: “OK, so that’s linked to weight loss, but not necessarily weight loss through fasting.”
Varady: “I really think all the benefits are through the weight loss. We have yet to tease apart the effect of fasting from the weight loss.”
And that’s all you need to know.
The front cover of the book claims “The only fasting diet proven by science.” But the person who has been researching this for 10 years still can’t “tease apart” the effect of fasting. Weight loss, by whatever method, is the factor that may deliver health benefits.