The Truth About Exercise

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Dr Michael MosleyThis is yet another mind opening  BBC documentary with Dr Michael Mosley. It’s well worth watching and uncovers some priceless information about exercise and weight loss.

Dr Mosley decides to go on a quest to find the absolute minimum amount of exercise he can do for the maximal health benefits in fear of developing diabetes like his own father.

He’s honest and says that knows he just won’t stick to a grueling exercise regimen so goes on the hunt to find something he will actually do. Fair enough!

He talks to Richard Ferguson and exercise physiologist Keith Tulley at the Loughborough University who measure his carbon dioxide and oxygen ratio to see how much fat and carbohydrate he uses (and therefore calories he burns) while running around track.

They find that he burns 16 calories a minute and give an eye-opening example of how much it would take to burn off certain foods with the example of a cappuccino, banana and muffin. They work out it would take 55 minutes of running at Michael’s pace! Not very encouraging.

So the basic message is that it takes us a long time if we try to use exercise to burn the amount energy we need to lose weight.


They also talk about eating too often and more than we should after exercise which can undo our hard work (and we iFasters refer to as ‘reward eating’ and is a huge issue for us women trying to lose weight!) and also discuss all the hidden benefits of exercise that lie deep within our body.

Dr Mosley then travels to Glasgow University to talk to a scientist Jason Gill who feeds him a large fatty cooked breakfast with sausages beans and bacon. He explains that the fat travels through our gut, into our bloodstream and while in the bloodstream causes a number of changes to our metabolismFatty Breakfast

All of these factors together act to increase the amount of fatty deposits in our blood vessels. This leads to weight gain, heart disease and diabetes to name just a few!

Then four hours after Dr Mosely’s fatty breakfast they take a blood sample and measure the fat content in his blood and find that it had doubled since before the meal. Yikes.

He says that not all types of fat are the same, so the fat that goes into our fat stores is not all stored the same way. He explains that subcutaneous fat just under the skin surface is not as bad as deep fat around the belly, organs and liver (which is a lot more harmful) and fat in our blood stream causes damage to our blood vessels.

He asks Dr Mosely to walk for 1.5  hours that night because walking triggers an enzyme called glycoprotein lipase which causes a decrease of fat in the blood and changes how our fat is stored. They then take another blood test and is there is a one third reduction in fatty deposits in his blood because it’s been moved to his muscle and ‘turned off’ by his body.

Interestingly, Dr Mosely explains that he’s a TOFI (thin on the outside fat on the inside) which he discovered after an MRI showing that he had fat around his organs. Fat around the organs is related to the onset of diabetes, and can be deceiving for thin people who think they must be healthy, and far from developing diabetes, because they don’t look fat on the outside.

He decides he still needs to find an easier way of exercising that can fit around his family life. Walking for 90 minutes every night just takes up too much time.


He takes a trip to the University of Nottingham and talks to Professor Jamie Timmons who tells him about  a study were 100 people were made to exercise four hours a week for 20 weeks and that all of them had a different results in weight loss, health markers and aerobic fitness. They found that the amount of exercise is not as important as the type of exercise and we all should really have personalised exercise depending on our genetics.

Some people are super responders (15%) and some non-responders (20% of the public) which is all down to 11 genes that we have. They took some more of Dr Mosely’s blood to see which one he was (but didn’t tell him until the end of the challenge).

The Truth about ExerciseThey tested his insulin sensitivity and his aerobic fitness and then started him on his challenge which is called the HIT protocol (high intensity protocol). This involves cycling for as hard as you can on an exercycle for 20 seconds followed by a 40 second break and then repeated another two times.

So this equates to one minute of exercise over the three minutes and needs to be done three times per week. Sounds pretty simple!

The idea behind HIT is that it breaks down glycogen stores where the glucose is stored in the muscle turns the glucose and energy from the blood.

This type of exercises activates to 70 to 80% of the muscle instead of the usual 30% with most generic exercise so therefore improves insulin sensitivity. It can also improve the VO2 max in some people but as some people are non-responders it might not have this effect. It usually takes about six weeks to improve fitness.

Dr Mosley takes an exercycle with him during the rest of his journey to search for answers, so he can do his three minutes a day three times a week. The Truth About Exercise

He then travels to meet with Dr James Levine an obesity expert who talks to him about NEAT which it stands for No Exercise Activity Thermogenesis which is basically the amount of calories we burn in our everyday lives such as when sleeping, walking and eating etc.

He explains that most people spend 12 hours a day seated at their desk and that being active controls genes that control fat in the blood. So it’s no wonder that being inactive causes us to rapidly gain weight. We can easily double our metabolic rate just by walking and moving throughout the day!

He makes Dr Mosley wear what he calls ‘fidget pants’ or NEAT underwear which have sensors that scan and track how much activity he does during a average 24-hour period.

They put a pair of pants on Dr Mosely, a waitress who moves around for most of her day and also an author who sits for most of his day, to compare the three.

Dr Levine explains that 80% of the population don’t exercise regularly and that keeping moving has a high impact on your physiology. We should and never sit down for even one hour at a time because our body ‘idles’ and starts to store fat.

Interestingly, he says it’s not enough to just go to the gym for a short burst at the end of the day. People who are seated most the day and to go to the gym for an hour don’t do enough to change their physiology. As predicted, the waitress had a higher ‘NEAT score’ and therefore a much higher metabolism and fat burning potential.

So can three minutes of HIT really have any effect on our physiology, metabolic rate and fat burning potential?


After four weeks of the HIT protocol they tested Dr Mosely again and he had a 15% reduction in blood glucose and his insulin sensitivity (great for warding off diabetes) had increased by 23%!  Unfortunately his VO2 Max did not improve because he’s a ‘non-responder’ (which they had predicted from his blood test results). This only means that his fitness would not improve from HIT but he still gets the fat burning and diabetes-fighting effects.


So whats the verdict?

Doing the HIT protocol for three minutes a day three times a week is great for warding off diabetes and heart disease. Strangely, they did not re-test the amount of fat in his blood which I’m sure most viewers would be interested in knowing!

For optimal health we should incorporate an HIT regime as well as improving our NEAT. But if we could only change one thing to boost our health and weight loss, it would be do do the HIT protocol which is quick and easy to stick to.

You can find out more about this documentary here. 

But what about for weight loss? Stay tuned for the iFasters Weight Off Plan for Women where you’ll find out just how much HIT you should be doing for maximum weight loss. Coming soon!




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