DR MICHAEL MOSLEY: Could fasting 16 hours a day REALLY help you keep cancer at bay?

In this week’s Health section of Mail on Sunday, we’ve revealed the truth about food and cancer. Contrary to popular belief, there is no one thing – whether that’s red meat, bacon, toast, roast potatoes or anything else we eat – that raises the risk significantly.

It’s overall diet that really matters. If we eat too much, we end up becoming overweight. But the fact that carrying too much fat, particularly around the middle, is linked to cancer is something that still surprises a lot of people.

If you’ve got fat around your tummy, you probably also have quite a lot of visceral fat – that’s the name for fat that builds up inside the abdomen and around the organs.

The cancers which are particularly strongly linked to excess fat are breast and bowel, two of our most common forms of the disease. So keeping to a healthy weight and keeping your tummy trim – ideally your waist should be less than half your height – are great ways to reduce your cancer risk. And I believe one of the best ways to do this is through intermittent fasting

And it is a problem, because it doesn’t just sit there, wobbling. Visceral fat is active, sending out signals to the rest of your body.

Some of these signals make your cells divide more rapidly, which increases your risk of cancer, while others cause inflammation, another big driver of cancer.

According to Cancer Research UK, being overweight or obese leads to about 22,800 new cases of cancer each year.

The cancers which are particularly strongly linked to excess fat are breast and bowel, two of our most common forms of the disease.

Cancers of the pancreas, oesophagus and gallbladder, all of which are extremely hard to treat, are also linked to obesity.

So keeping to a healthy weight and keeping your tummy trim – ideally your waist should be less than half your height – are great ways to reduce your cancer risk.

According to Cancer Research UK, being overweight or obese leads to about 22,800 new cases of cancer each year. (File photo)

And I believe one of the best ways to do this is through intermittent fasting.

It can not only cut your risk of developing cancer but may even boost the effectiveness of treatments such as chemotherapy, if you are unlucky enough to need it.

HOW 5:2 COULD HELP FIGHT BREAST CANCER

Seven years ago I wrote a book, The Fast Diet, with journalist Mimi Spencer, in which we outlined the potential benefits of going on a 5:2 intermittent fasting diet. This is one where you reduce your calories to about 600 twice a week.

I suggested it would not only help you lose weight, but, according to studies carried out on animals, might also help cut your risk of developing cancer.

Since then, studies in humans have indicated the same.

Seven years ago I wrote a book, The Fast Diet, with journalist Mimi Spencer, in which we outlined the potential benefits of going on a 5:2 intermittent fasting diet. This is one where you reduce your calories to about 600 twice a week

British scientists Dr Michelle Harvie and Professor Tony Howell have carried out studies that showed intermittent fasting helped improve insulin resistance in one group of women. 

Insulin resistance is a measure of how much of the hormone your body has to produce to bring your blood sugars down after a meal.

Another group of women who dieted every day also lost weight, but didn’t see the same insulin improvement. This is important because having high levels of insulin increases your cancer risk.

So a combination of weight loss and improvement in insulin sensitivity could be highly beneficial.

In another more recent study, Dr Harvie asked 23 overweight, pre-menopausal women at high risk of breast cancer to cut back their calories, two days a week, for one menstrual cycle. 

This time, as well as standard tests, they agreed to have breast biopsies. Over the course of a month, the women lost an average of three kilos (more than 6 lb), most of it body fat.

In most of the women there were significant changes in the activity of genes associated with breast cancer.

Bigger studies would be needed to really prove intermittent fasting, rather than weight loss generally, was responsible. But the results are interesting.

SKIPPING BREAKFAST COULD BE A GOOD IDEA

In The Fast Diet, I also wrote about a different form of intermittent fasting, one called time restricted eating. It’s also known as 16:8, and you don’t worry about calories when doing this plan. Instead, you limit the hours within which you eat your meals.

Many of us don’t finally finish eating and drinking until about 10pm thanks to a late-night snack, and then we start eating again soon after we wake up. That means we go without food for about nine hours.

DO YOU HAVE A QUESTION FOR DR MOSLEY? 

Email [email protected] or write to him at The Mail on Sunday, 2 Derry Street, London W8 5TT. 

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The idea behind time restricted eating is to extend the length of your ‘overnight fast’ to 12, 14 or even 16 hours by finishing eating earlier in the evening and starting again much later – basically, skipping breakfast the following day.

It has been shown to help people lose weight. But can it also reduce your cancer risk?

In a large study, 2,400 American women with breast cancer were randomly allocated to either a low-fat diet or given general health advice.

They were then followed over the next seven years to see if going on a low-fat diet made any difference to the risk of breast cancer recurring. The answer was a resounding ‘no’.

Despite reducing their fat intake by 19 per cent, the low-fat dieters were no better off than those in the control group.

But the great thing about this study, from the point of view of researchers investigating time restricted eating, is that the women were asked to keep detailed records of when they ate.

The women whose diaries showed that they had fasted for more than 13 hours a night had 36 per cent less chance of a breast cancer recurrence than those who had been fasting for under 13 hours.

There is a lot more information about intermittent fasting, foods and their impact on cancer in my latest book, the Fast 800. You can also find additional information at thefast800.com.

Low-cal diet hope for chemo patients

Could a strict five-day diet help in the fight against cancer? That’s exactly what scientists across the world are trying to find out.

They are looking into the Fast Mimicking Diet – the brainchild of Professor Valter Longo, who heads the Longevity Institute at the University of Southern California in Los Angeles.

He created a diet where you live on about 800 calories a day for five days, then eat normally for the rest of the month.

This cycle can be repeated every one to six months, depending on your diet goals. Prof Longo believes that if you drastically reduce food – and therefore energy supply – cells go into ‘a highly protected non-growth mode’. In other words, they hunker down and wait for better times.

He believes this diet could also help patients going through chemotherapy, one of the main treatments for cancer. Chemotherapy drugs kill off cells that grow rapidly, which is what cancer cells do.

But other healthy cells – such as hair cells and those in the gut – also divide rapidly. This is why treatment can cause hair loss and nausea.

The theory is that if you could slow down the growth of normal cells by fasting prior to chemo, that might protect them during the treatment, while still leaving the tumour cells vulnerable to attack.

There are medical trials happening right now that are trying to find out if Prof Longo’s diet might do just that.

He is adamant, however, that people should not try to do this without consulting their doctor.

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