Willpower doesn't exist. Why so much of your health isn't your fault

A giant mug of instant black coffee and no food is not what you'd expect the host of a wellness podcast to have for breakfast.

Yet it's what Dr Chris van Tulleken, who hosts the BBC's What's Up Docs alongside identical twin brother Dr Xand confesses to having.

"I'm approaching middle age so don't want to eat all day. My way of not eating all day is not eating breakfast," he says.

It's this kind of honesty about not leading the perfect life and struggling with the stuff they know they should do but still don't, that makes them so relatable.

The brothers are both medical doctors who've become household names through their TV and radio work - they present children's series Operation Ouch! and Dr Xand is one of BBC's Morning Live resident experts while Dr Chris is well known for his bestselling book Ultra-Processed People.

On the podcast, they often disagree with each other over competing claims about health and wellbeing, much like they do in real life.

Xand laughs after Chris says it's a hard job working "with a brother like Xand who is so intensely annoying".

But really the brothers love working together and Chris admits that they started the podcast "quite selfishly as we were just trying to answer our own questions".

"But it turns out our problems are similar to everyone else's."

They say the podcast has changed their lives for the better and share what they have changed about their behaviour over the course of more than 30 episodes.

Like most of us, the brothers assumed eight hours was the gold standard for sleep and anything less was a failure. Now, they're far less dogmatic.

The brothers say a healthy range of sleep can be anywhere between six and 10 hours.

"There's so much anxiety around getting eight hours but some of the most important things in my life, like raising kids, I've done sleep deprived," says Chris.

Realising that everything from winning wars to completing exams were often done with very little sleep, made them understand that sleep deprivation can sharpen your focus in the short term.

Xand says this helped him "shed all that anxiety" around optimal sleeping patterns and times.

"It no longer dominates my life and I think about it a lot less."

He also feels a lot more comfortable taking naps when needed and says he will sometimes "have a 20 minute sleep if I'm exhausted".

The pair both find saying "no" difficult and Xand says it can feel "almost physically painful."

They have now learnt the "power of the pause". If something does not require an immediate decision, they now ask for more time to think about it so they don't feel pressured into saying yes.

Chris says this has helped him have difficult conversations he may otherwise have put off. However, he admits he's still figuring out how to be more forceful.

"I know I should do, but somehow I'm not and I know I need to focus on that."

The podcast episode on this topic also taught them that they needed to work out what their values are and then weigh up whether requests fitted in with those. For Xand, his priority was spending more time with his wife and two sons.

He has since managed to say no to a number of things that he would have otherwise gone along with for an easy life.

"I recently said no to a very big and important work thing even though there was a lot of pressure on me to do it, but it didn't fit with my other commitments and what I wanted to do."

One of the most practical tips that has stuck with the brothers is how they brush their teeth.

The small act has become a mindful task and Xand explains he's totally changed the way he brushes.

"My wife, Dolly, hasn't complained about my bad breath since the episode.

"I use brushes for flossing, hold my toothbrush at a different angle and I don't look at my phone while brushing."

While Chris is shocked that his brother ever used his phone while brushing his teeth, he agrees with how powerful the changes have been.

"It's about the angle of the brush, being more gentle and having a better picture of what you're trying to achieve - you want to clean every surface of every tooth."

Many people believe that struggling with diet, exercise or breaking habits is down to personal weakness, and Xand shares those feelings.

"I feel lazy and inadequate most of the time.

"I go to Manchester every week and I usually arrive late after a long train journey and I order a takeaway and do no exercise then I beat myself up about it."

Their expert guest on this podcast episode, psychologist Kimberley Wilson, helped Xand understand that "there's no such thing as willpower".

Willpower is not this magic thing inside you, instead your ability to stick to something is "about the way you've arranged the world around you," he says.

For example, by planning ahead and thinking about what you'll have for dinner, you can more easily ditch the takeaway and eat something healthy.

Since the episode, Xand has managed to increase how much exercise he is doing, but still doesn't enjoy it.

"I just get on the exercise bike and have those negative thoughts while I do my workout," he says.

Another simple change he's made is taking a bag of apples with him on his regular commute between London and Manchester, rather than buying unhealthy snacks on the train.

Chris realised willpower wasn't about increasing your tolerance to distress and suffering, but simply being more organised.

"I've started batch-cooking which now releases time for me to do things like read with my daughter."

For all the changes they've embraced, the brothers are the first to admit they don't follow every bit of expert advice.

Take sunscreen, for example. "A dermatologist gave us really good advice," Dr Chris says, "but there's something about the sun that feels so powerful. Academically, we know sun exposure is bad and causes cancer but we still find ourselves drawn to it."

That tension - between what we know and what we do - is at the heart of their podcast.

If there's one thing the doctors hope listeners take away from the show, it's that struggling with health isn't a personal failure.

"So much of your health and well-being isn't your fault," says Dr Xand.

"There are loads of forces trying to take your money, attention and time away from the things that matter. What we're trying to do is sweep that out of the way, help you identify your values and align your life with them."