Thu, Sep-24-20, 02:46
Olympic medallist running for five days without food to prove we don't need carbs
James Cracknell is running for five days without food to prove we don't need carbs - is he right?
As James Cracknell runs 100 miles on zero calories to promote low-carb diets, we consult the science
“Society is eating too many carbs,” proclaims James Cracknell, the rowing champion and double Olympic gold medallist, who is currently running 100 miles in five days while drinking only water and consuming zero calories.
It may sound like a foolhardy fasting challenge, but the 48-year-old British athlete has undertaken it to prove a point.
On his social media account, he explained that he was embarking on the #zerofive100 challenge on Saturday in order to “add to evidence that a low carb diet is an effective therapeutic treatment for diabetes, and beneficial for pre-diabetics," and to show that fat alone can fuel the human body.
So, is this just celebrity endorsed food faddishness, or - given that this week we were told that over half a million British people have Type 2 diabetes without realising - does Cracknell’s experiment raise an important question for the 4.7 million people living with diabetes in the UK?
Joined by three doctors and three healthcare professionals on the route from Henley-on-Thames to Bristol, by Sunday evening he had completed 45 miles of the challenge and told his followers that metabolic testing has shown he was no longer burning carbs but his energy levels were “surprisingly good”.
So does a low carb diet, which puts the body into a "fat-burning" ketogenic state, help those who suffer from diabetes? And is Cracknell's five day approach too extreme - do we all need at least some carbs?
“Five days with a zero calorie intake is incredibly dangerous as it is putting yourself in danger of suffering with exhaustion, fainting and possible stroke," says Dr Aragona Giuseppe, GP and medical advisor at Prescription Doctor. "It can be done as long as the person is fit and healthy and consuming plenty of hydrating fluids each day, but when your calorie intake is too low, or in this case non-existent, your body is not getting the vital nutrients it needs to properly function or remain healthy.
“Your immune system is also being compromised due to the lack of sustenance, vitamins and minerals. Some would argue that it’s incredibly irresponsible to do this kind of long term fasting in the public eye, especially when there are so many risks involved. However, it is true that yes, some research shows that a low carb diet can help with the treatment of diabetes. I would suggest for those with diabetes to look into a low carb diet, but fasting for long periods of time should not be promoted or glamorised.”
Registered nutritionist Rhiannon Lambert agrees. “Fasting this extreme is most certainly not setting a good example nor encouraging healthy relationships with food.
"Of course managing your glucose levels is a crucial part of managing diabetes but by selecting a diet that works for you with the right amount of carbs (found in vegetables, wholegrains and pulses) you can eat well and live well too. Each case is going to be unique and require unique nutrition.
"As for exercising like this on so little fuel, yes it’s possible as fat is a source of energy, but not safe for many reasons. Carbs are the bodies preferred fuel source and also impact our brain function. As an Olympic athlete James is already at a good level of fitness and has a measured understanding of his body. I urge everyone not to try this at home without medical and nutritional supervision."
According to Bupa Health Clinics medical director Dr Arun Thiyagarajan, the human body can burn fat for energy as Cracknell says - but to perform at our best we need to consume a healthy, balanced diet. "While crash diets or short-term challenges may seem appealing, the results can often be short-lived and, in some cases, can even be harmful to our bodies. Instead, people should focus on making smaller, sustainable changes, which will help manage health and weight in the long-term," he says.
"The body is able to use both carb and fat as a fuel. This does not translate into it being ideal to therefore use one above the other. Carbs the preferred source of fuel for both brain and muscles. Other fuels can be used, but that doesn't mean it is physiologically advantageous or of health benefit to do so long term," adds registered dietitian Laura Clark.
As for diabetes, this is caused by too much fat accumulating inside the liver and pancreas. It's true that losing weight and being active is an effective prevention, according to the NHS. And, according to some, a cure.
The research of Professor Roy Taylor, a diabetologist and the author of Life Without Diabetes: The Definitive Guide to Understanding and Reversing Type 2 Diabetes covers the reversal of type 2 diabetes and seeks to show how diets and weight loss can put diabetes into remission, proving that it is not an “inevitably progressive disease”. Taylor recently co-led a study which showed more than a third of people with Type 2 diabetes who took part in a weight management programme delivered by the NHS through GP surgeries remain free of diabetes two years later.
A growing body of scientific research also suggests that adopting a low-carb diet in particular (in which your body produces ketones from broken down fats in the liver for energy, rather than relying on insulin to convert carbohydrates) may have specific benefits for people with Type 2 diabetes and improve insulin sensitivity.
When a Danish study carried out in 2019 by scientists from Aarhus University, the University of Copenhagen and Bispebjerg Hospital examined whether a low-carb diet would improve the insulin response in patients withTtype 2 diabetes, it found that it did.
A lower carb diet meant less insulin was required in the bloodstream after the low-carb meals - giving the body a chance to recover while the liver and pancreas shed the fat impairing normal functioning. Patients with type 2 diabetes improved their ability to regulate their blood sugar levels by eating food with a reduced carbohydrate content and an increased share of protein and fat.
A total of 28 type 2 diabetic patients were examined during the 12 week cross-over study, published in the journal Diabetologica. During six weeks of the study, patients were randomly assigned to a low-moderate carb diet or a low-fat diet, and then switched for the second half of the study.
"We hypothesised this combination would improve glucose control in Type 2 diabetics and reduce the fat content in the liver reducing the risk of non-alcoholic liver disease. This was shown to be correct,” reported Dr Thure Krarup, from the Department of Endocrinology at Bispebjerg Hospital. “The study shows that by reducing the share of carbohydrates in the diet and increasing the share of protein and fat, you can both treat high blood sugar and reduce liver fat content. Further intensive research is needed in order to optimise our dietary recommendations for patients with type 2 diabetes.”
But how low-carb should you go? According to this study, a low carb diet can be defined as 10-25 percent of calorie intake. Depending on a person's calorie requirements this could be as low as 50g of carbohydrates per day, or 3 slices of white bread, which is very different approach to fasting with no calories or carbohydrates at all for five days.
"In our study we used 30 per cent, so the diet was a moderately reduced carbohydrate diet. The reason for this being there's a need to have a certain amount of carbohydrates in a healthy diet and also that the diet should be convenient and tasty."
The evidence-based Diabetes UK nutrition guidelines also suggest that low carbohydrate diets are helpful for people with Type 2 diabetes. Although they recommend an “individualised approach to diet taking into consideration the person’s personal and cultural preferences”, they also state that people at risk of diabetes should “eat more of certain foods such as vegetables, fruits, wholegrains, fish, nuts and pulses” and “less red and processed meat, refined carbohydrates and sugar sweetened beverages.”
According to Diabetes UK, a low-carb diet means cutting down on the amount of carbohydrates you eat to less than 130g a day. “To put this into context, a medium-sized slice of bread is about 15 to 20g of carbs, which is about the same as a regular apple. On the other hand, a large jacket potato could have as much as 90g of carbs, as does one litre of orange juice,” it states. But it points out that low-carb eating shouldn’t be “no-carb eating”, and it’s important especially for people who take medication to manage their diabetes (and especially insulin), to seek advice from medical professionals first in order to safely adapt their diet - and it might not be right for everyone.
"A low-calorie diet is not safe or suitable for everyone with Type 2 diabetes, such as people who need to take insulin. So it is important to get medical advice before going on this type of diet," the NHS states. "There is evidence that eating a low-calorie diet (800 to 1,200 calories a day) on a short-term basis (around 12 weeks) can help with symptoms of Type 2 diabetes. And some people have found that their symptoms go into remission."
Some experts believe the science is not yet fully conclusive. As the Danish study notes, although a trend towards recommending a diet reduced in carbohydrate content is acknowledged, more research is needed into dietary recommendations for treating Type 2 diabetes.