"WHAT'S LAUGHTER YOGA?" Gizzi Erskine exclaims, reading a tweet as we chat between shots in the studio. "The world is going fucking crazy, I tell you."

Now here's a woman who doesn't mince her words. "Look at Instagram today and it's pictures of what you can make with avocado and courgette," she says. "It's soul-destroying, but unfortunately the diet industry is such a minefield."

Erskine's thousands of social media followers know how vocal she can be – she doesn't pull her punches when it comes to talking about – and eating – food. "In this country we find it so much easier to latch on to cutting out food groups – cutting out carbs, wheat, dairy and gluten. But we don't understand why we're doing it. Health," she says, "has gone mad."

Photography by David Harrison

If anyone should champion the fight against food fads, it's Erskine. The chef, writer and former body-piercer loves her meals, and her Instagram boasts more burgers, cocktails and cats than smoothies, chia seeds and headstands. Yet she's a picture of health: she bounds around the studio with relentless energy, her skin is glowing, and that lustrous beehive is all real. So what's the catch?

"I've tried every diet under the sun and wanted to be more considerate about what I was putting in my body, and not give any food bad press. I wanted to look at ways I could still eat what I wanted." Cue a new cookbook, Gizzi's Healthy Appetite, which contains pages crammed with, dare I say it, carbs, fat and meat.

If you're horrified, don't be. Her latest book (she's produced three before) isn't about overindulgence, nor is it about rapidly dropping pounds by detoxing on pond water. Erskine worked with a nutritionist on her previous projects, relishing the chance to be taught the intricacies of what our bodies need and how they work.

If you want to eat normal white pasta, just do it. But look for quality wheat

This helped the 35-year-old chef to create balanced recipes involving all food groups; recipes that will ultimately help us make conscious decisions about the ingredients we use to lead a healthy, sustainable lifestyle, without sacrificing dishes we love. "If you want to eat normal fucking white pasta, just do it!" she says. "But look for the best quality durum wheat. Spend a tiny bit more and eat a tiny bit less."

And it's not just pasta that we can keep eating. The book took eight months longer to write than planned, because Erskine was so set on getting the content and ingredients spot-on. Divided into sections according to food textures (squidgy, crunchy, etc), it offers recipes to suit every craving, from oozy mozzarella cheese (yes, cheese – and it's fried), to fresh bhel puri salad.

The pages feature recipes that sit alongside dynamic, fresh pictures – thanks to food fiend and photographer the Gaztronome. There are piles of lamb, houmous and pita bread, mounds of bolognese (using white wine), and one of her favourites – chicken kievs – doused in breadcrumbs and exploding with butter. "BUTTER!" she shouts at me, her face beaming. "Good-quality, grass-fed butter is a proven superfood now. I'm very pleased about this."

Erskine's enthusiasm for superfoods and attitude towards eating is not to be mistaken for yet another of the clean-eating fanatics saturating today's media. She's openly wary about the influence that some health-food bloggers have on women and younger, impressionable teens who are too keen to #eatclean. "We're going to have a nation of young people who've been brought up eating like this. What's it going to be like sitting around the dinner table in a few years' time?

"I'm frustrated by the health writers that are coming out at the moment, without a cooking background or without a background as a dietitian or nutritionist. Their philosophies are based on their own illnesses, and it's tagged 'clean eating'. It's so over-the-top, and it's taken the love out of food. It's taken the love out of cooking."

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Instead of cutting out food groups, Erskine's focus is on using quality ingredients – across every food group – and, as long as it's fresh and from a good source, it shouldn't be neglected. "People are giving up meat because they understand veganism is actually better for you, but why? Meat is actually really good for you – we're carnivores. It's about not overeating it, and eating good-quality meat." She recommends spending as much on animal products as we can afford – buying from butchers or small producers that raise animals ethically, which in turn makes us more conscious of our health and the environment.

Erskine does admit that focusing on the quality of produce calls for more money to be spent on food, but she's adamant it's the way to go – and eating better-quality protein less often is the answer. Other healthy essentials include a well-stocked cupboard of aromatics (garlic, ginger, chilli), pulses and grains and – crucially – a variety of different oils: extra-virgin for dressings, rapeseed for cooking ("it's sustainable and British"), and coconut oil, but only for curries and sweet food. "One of my biggest pet hates is cooking everything in fucking coconut oil," she laughs.

She read chef's bible Larousse Gastronomique before bed and slept with it under her pillow, hoping to absorb the recipes

That's not her only problem with healthy food trends: "Raw puddings annoy me – like calling something a raw brownie. It's not a fucking brownie, so let's not call it one." There's no banning of sugar here, thankfully, although she doesn't go crazy with it (moderation, remember). I make her tea that comes with milk and sugar ("just a quarter") and she happily tucks into millionaire shortbreads, and more, as we take a break between shoots. Meanwhile, the new cookbook has dessert recipes rigorously tested to be flavoursome but nutritious. And they're not raw.

"I wanted to look at it from a nourishing attitude," Gizzi says of her new book. "It meant there were no holds barred, and I really feel like the chapters are divided into sections of mood: something crisp and lighter or oozy and soothing. I think as a collection of recipes it’s my strongest yet. I took six months off last year to write the book in Spain. I was running to the markets, then cooking and writing three or four recipes a day."

Gizzi's Healthy Appetite by Gizzi Erskine is published by Mitchell Beazley, £25 (octopusbooks.co.uk)

It's this – excuse me nabbing the book's name – healthy appetite for food that's led to Gizzi's heavy involvement in London's street-food scene. One of her latest ventures is London Union, a project she's working on with Street Feast's Jonathan Downey, and Henry Dimbleby, co-founder of natural fast-food chain Leon. With backing from the likes of Nigella Lawson, Jamie Oliver and Yotam Ottolenghi, the Union is a company looking into a permanent, large food market in London (hopefully as early as next year), with up to 15 local markets following over the coming years. "We're looking at European markets and seeing how you can have a really great glass of wine but can buy and eat really great produce at the same time," she says. "We want to make produce more accessible and more tactile than at a farmer's market."

As much as she loves cooking with top-drawer goods (this is a girl who read chef's bible Larousse Gastronomique before bed and slept with it under her pillow, hoping to absorb the recipes inside), Erskine's passion lies heavily in eating on the street. She thanks her half-Scottish, half-Polish "rad" mum for getting her into different cuisines, and it was travelling to Thailand and eating in the markets there at a young age that sparked her curiosity for ingredients. Today, she's an expert on London's street food scene, and she loves the long-term success it creates: "People are coming out and making businesses within street food now – they don't even need to think about restaurants. It offers longevity."

It offers accessibility, too. Erskine took the hardcore route of training – she came top of her class at Leith's and has worked in numerous kitchens while doubling as a body-piercer in her spare time – but recognises that street food offers new opportunities for the naturally skilled. "Talent is talent, so if you're super-talented you can go through the unconventional route of not having trained professionally."

And there's plenty of talent out there – Le Bun, a French-American street stall, is one of her favourite traders, along with Smokestak (American BBQ) and Bleecker St, owned and run by Zan Kaufman, who quit her job as a lawyer in New York City to set up a now-crazy-successful burger van in London. "Zan does the best burgers I've ever had – ever," Erskine says. "She's fucking great."

I don't see myself as different from a guy. I've been bred with a sense of being able to achieve what I like

I suggest to Erskine that Kaufman is one of many prominent women in London's street food scene – a place where there seems to be a more even split between men and women compared with the capital's restaurants. "Yes, you're absolutely right." she says. "I've never thought about that before."

But it's something she feels shouldn't be an issue: "I've never really seen myself as different from a guy. If I rise to it now it's making it more of an issue than I was ever brought up with. I feel like I've succeeded because I've been bred with a sense of being able to achieve whatever the hell I like. I've just always thought I could do the same as a guy, so in terms of career and general life achievements, I don't see us as any different."

It's this kind of strong-minded attitude that's helped get Erskine to where she is, and there's plenty we can learn from her mentality, while – hallelujah – eating toast, with butter. "The cool thing is we're now taking responsibility for what we eat. But it doesn't have to be faddy the whole time."

So juice your kale within to an inch of its life, but use it to supplement, and never substitute, your meal. Source your meat from a good butcher, up your intake of high-quality proteins and don't be scared of fat (but hold that coconut oil). It's refreshing advice that's simple and sustainable.

As for that bread? "The problem with wheat is we've manufactured it to the point of being shit," she says. "Go for one with a good wheat and natural yeast. I'm like 'Whatever, have it – it's no big deal.'" Amen to that. ■

Hannah Summers is a contributing editor at Foodism. Follow her on Twitter at @BurgersAndBruce

Want to see some of her recipes? Here's one for grapefruit pavlova.