BOSH!’s Ian Theasby: ‘When a child comes into the equation, you want to be there for as long as possible for them’

Turning 40 can be a shock to the system. For childhood friends and business partners Ian Theasby and Henry Firth, the big 4-0 triggered a whole “new philosophy”. “We both looked at ourselves in the mirror and recognised the fact that yes, we had been eating lots of plant-based food, but maybe we hadn’t really been doing it as well as we probably could have. We were maybe eating a little bit too much sugar. We were both drinking alcohol. We both weren’t prioritising sleep and rest,” says Sheffield-born Theasby.

The duo, who launched their hugely successful plant-based food company, BOSH!, almost a decade ago (six cookbooks and counting, one million Instagram followers), also became fathers around the same time. “When a child comes into the equation, you are reminded that you want to be there for as long as possible for them, and the best way to do that is to give yourself a fighting chance at real longevity.”

And so, their new philosophy emerged: more plants – tonnes more of them. Hence the title of their new recipe collection, BOSH! More Plants. “We think eating more plants is the best way for people to maximise and optimise their health. This book is essentially showing people that if you eat plants, and a good variety of them, you can turbo-charge your health and your energy and everything else that comes with it.”

It’s working for them so far. Theasby says he’s feeling “very, very good”, that they’ve both “lost a lot of weight, in a good way, it’s positive weight loss” and their families “are constantly commenting on how they think we look good”. Their energy levels are also “enough to keep two toddlers at bay”. Alongside all the plants, they’ve slashed sugar and gone teetotal, and Theasby really doesn’t miss the booze. “It was time. Both of us recognised we were enjoying the feeling of waking up fresh more than the feeling of having a couple of drinks in the evening,” he says. “Not being hungover is a cheat code to productivity. You wake up fresher every single morning, which means you’re probably getting exercise done in the morning, which means you feel more energised throughout the day, so you’re more productive.”

As a result, they’re feeling fitter than ever before too. “Henry’s doing triathlons; I’m running ultra marathons,” says Theasby, “We’re not out to win these things, but to compete in them is very satisfying and keeps you on your toes, health-wise.” They both also wear Whoop trackers (“We’re not sponsored by them!”) which monitor health and pace of ageing. So Theasby is 41, but Whoop reckons his health is 8.1 years younger than that, and for Firth, his biological age is five years younger than what his birth certificate states. “That’s because of prioritising sleep, prioritising the correct food, prioritising exercise and not drinking booze,” says Theasby.

You could argue they’ve gone a little bit Silicon Valley tech bro-woo-woo with the longevity focus and time-intensive exercise regimes. They even namecheck controversial billionaire biohacker Bryan Johnson (who infused himself with his 17-year-old son’s plasma in an effort to extend his lifespan) in the book. “The way I would describe Bryan Johnson is like an army ranger going into unknown territory for the benefit of everybody else. So what he does is, he expands the playing field,” says Theasby. “He might be doing something absolutely mental, like super, super extreme, but he’s just widening the possibility [for the rest of us to learn from].” He argues Johnson pushes limits with his own body, but tends to end up “highlighting the obvious”, like how vital sleep is, and the benefits of saunas for detoxification, and eating earlier in the day for better digestion.

Eating more plant-based food might be a no-brainer to some too, but fitting 30 plants a week into your diet – which is what the BOSH! lads and many other nutritionists, food writers and medical experts are now recommending – can be daunting. “Thirty plants a week does seem like a lot. However, there are ways and means of hacking the system and getting more plants on your plate,” says Theasby, who recommends chucking a handful of mixed seeds and nuts on your granola in the morning, which, alongside some chopped fruit, sultanas and oats, could get you up to 10 on day one. “You just have to approach it as if it’s not a chore.”

How do they get their toddlers to eat a diet that doesn’t consist solely of baked beans and cucumber sticks though? Theasby says his trick is “giving them variety and not making a big thing out of it. It’s almost like, just pop the food down. That’s what we’re having today. It’s not like, ‘What do you want to eat?’ Or, ‘Is this nice?’ It’s just, the food appears in front of them. They look at it and just go, ‘I’ll have a bit of this, I’ll have a bit of that’.”

“My kid is two. Henry’s kid is three. I’m pretty sure we’re not out of the weeds yet. I’m pretty sure there’s rocky patches to come. But for now, we’re – touch wood – in a good place,” he says.

If you’re thinking Theasby is too much a paragon of the perfect diet, he’s still a (dark) chocolate fiend. “Every night, once I’ve eaten my dinner and I’m sitting down to watch some football or whatever, the chocolate comes out,” he says. “I’ll have two or three squares of some nice dark chocolate, delicious, with some nuts and raisins. And then, if you put your chocolate and your raisin and your nut in your mouth at the same time, it’s like having a Dairy Milk Fruit & Nut!”

BOSH! More Plants: 30-Minute Plant-Based Meals by Henry Firth and Ian Theasby is published in hardback by DK, priced £22. Photography by Haarala Hamilton. Available now