Amelia Freer has one word of advice for convenience food fans who say they 'don't have time to cook from scratch'.

"If you don't have time for health, you need to eventually make time for disease."

It's a stark warning from the no-nonsense 40-year-old nutritional therapist, blogger and author, who boasts James Corden, Sam Smith and Boy George among her celebrity clientele, but she's passionate about inspiring positive change.

"We used to [cook from scratch] in the old days, before convenience food existed - it's only convenience food that told us we don't have time any more and we don't have the skill. We've learnt to not make the time or prioritise it, and now we feel incapable.

"We've got our priorities wrong," she enthuses. "Preparing and thinking about food has gone to the bottom of our list."

Freer knows from experience the impact eating badly can have.

In her mid-20s, while working as Prince Charles' personal assistant, she survived on a diet of pre-prepared food and sugary tea, and was plagued by IBS and acne.

"I had really bad digestive problems, really bad skin problems, really low energy, I was always getting ill, I was always run down," she recalls. "It wasn't anything sinister like a disease, but I just wasn't a healthy girl.

"I think a lot of people aren't healthy," she adds. " As humans, we tend to make do and put up with bad health, you get used to it, as opposed to saying, 'No, I deserve to feel excellent, I deserve to have optimum health'."

Freer eventually quit her job and enrolled on a four-year nutrition course, which changed her life.

"I started to learn about nutritional therapy, which is working with individuals to help improve their health, through the use of food. It's amazing how quickly someone can feel better, above and beyond weight loss - they feel a lot better with various symptoms when they improve the quality of the food they're eating."

Sam Smith summed it up when he posted a picture on Instagram of Freer's bestselling debut book Eat. Nourish. Glow., published early last year, with the caption: "Amelia Freer has helped me lose over a stone in two weeks and has completely transformed my relationship with food... It's not even about weight loss, it's about feeling happy in yourself."

She's not a fan of our reliance on sugar - "The amount of access we have to sugar now is detrimental to our health. It's so important that people become more aware of it" - but neither does she like the word 'diet'.

"I don't endorse or support any diet. If someone comes to me wanting to know about a diet, then I'm afraid they'll be disappointed. Everyone's too quick to turn things into extremeness and fads, and I think that's really disappointing."

So is the 'moderation' approach better?

"I hate that word because it frustrates people, but I think we have to find balance," says Freer. " Everyone's different. What works for some people doesn't work for others. Some excel at being vegan, others really, really don't.

"I'm never judgemental, to say that there is only one way for people to eat. We're all unique and we cannot take a one-size fits all approach."

That said, if you are going to have something naughty, like a piece of cake, make sure you savour it.

"If you want to be healthy and you like to have your piece of cake, it's much better to have that slice, sit down with it and actually enjoy it," says Freer. "Rather than this unconscious picking, where you feel a bit guilty and don't realise how much you're eating. If you're going to have them [treats], do it in a healthy way."

So there you go, permission to eat cake (sort of) - and be healthy. Feeling inspired? Here are three recipes from Freer's new book Cook. Nourish. Glow. to try at home...

:: SUPER GREEN SOUP WITH CASHEW CREAM

(Serves 4)

Olive oil

1 onion, chopped

1 head of broccoli, cut into florets

3 handfuls of fresh or frozen peas

700ml vegetable or chicken stock

1 small bag of baby spinach (approx 250g)

1 green chilli, chopped, to sprinkle on top

A small handful of fresh parsley, chopped, to serve

For the cashew cream:

150g raw cashews

300ml hot water

1 clove of garlic

Zest of 1 lemon

A few hours before making this soup, prepare the cashew cream. Put the cashews into a bowl, pour over the hot water and leave to soak for at least two hours. Once the cashews are tender, drain and put into a food processor, along with 300ml fresh water, the garlic and lemon zest, and blitz until completely smooth and creamy. Set aside.

Heat one tablespoon of olive oil in a large saucepan, and sweat the onion until translucent. Add the broccoli and peas to the pan, cook for five minutes, then add the stock - the vegetables should be just covered (you may need to add a little extra water). Bring to the boil, then simmer until the broccoli is tender, for roughly four minutes. Don't overcook the vegetables or they will turn a dull green.

Using a stick blender, start blending the soup, adding a handful of spinach at a time - the spinach will cook as it's mixed into the soup. Blend until the soup is smooth and thick, then stir through half the cashew cream.

Serve in bowls with a swirl of cashew cream on top and fresh parsley and chilli, if using, scattered over.

:: INDIVIDUAL FISH PIES

(Serves 4)

1 x 400ml tin coconut milk

1tbsp garlic-infused oil

Juice and zest of 1 lemon

2 bay leaves

300g cod fillet (approx 2 small fillets)

300g undyed smoked haddock

A splash of white wine (optional)

Sea salt and freshly ground black pepper

1 large celeriac, peeled and chopped into equal-sized chunks

2 sprigs of fresh thyme, leaves picked

1 1/2tbsp unflavoured coconut butter

150g raw king prawns

3 spring onions, green parts only, thinly sliced

A small handful of fresh chives, chopped

1 tbsp fresh parsley, chopped, to serve

Put the coconut milk, garlic oil, lemon juice and zest and bay leaves into a large, deep pan. Add the cod and haddock and bring to a gentle simmer. Poach the fish for approximately 10 minutes until the flesh flakes easily.

Remove the fillets and set aside. Add the wine (if using) to the poaching liquid, season to taste with salt and pepper, and leave to simmer over a low heat while you make the celeriac mash.

Preheat the oven to 200C/180C fan/gas 6.

Put the celeriac into a pan of boiling water and boil with the thyme leaves until tender. Drain and mash with the coconut butter, and season with salt and pepper.

Flake the fish and divide between four individual ovenproof dishes (or you can use one big dish). Add the prawns, spring onion and chives to each pot and pour over a quarter of the poaching liquid - it should have thickened slightly by now. Top with celeriac mash and bake for 40-50 minutes, or until the pies are golden on top.

Scatter with chopped fresh parsley and serve with steamed greens, such as broccoli, peas or rainbow chard.

:: COCONUT YOGHURT JELLY WITH RASPBERRY AND FIG COMPOTE

(Serves 2)

4 fresh figs

4 dried figs, soaked overnight, then rinsed

120g raspberries

1/2tsp vanilla essence or seeds from 1/2 a vanilla pod

6 fresh mint leaves

6 leaves of gelatine

500g coconut yoghurt

Chopped Brazil nuts, cacao nibs and small mint leaves, to serve

Blend the fresh figs with the soaked dried figs, raspberries, vanilla essence or seeds and the mint leaves until smooth, slightly thickened but still of dropping consistency. Add some soaking water if needed. Divide this mixture between two glass serving jars or small tumblers.

Soak the gelatine leaves in water for 10 minutes. Once softened, heat them with four tablespoons of water until dissolved; add this to the coconut yoghurt and whisk the mixture until well incorporated. Pour on top of the fig mixture and place in the fridge to cool.

Just before serving, sprinkle with chopped Brazil nuts and raw cacao nibs. Decorate with small mint leaves.

:: Cook. Nourish. Glow. by Amelia Freer is published by Michael Joseph, priced £20. Available now

THREE OF THE BEST... Rye breads

:: Sainsbury's Sprouting Rye & Wheatgerm Boule, £1.25, Sainsbury's

Soft and pappy beneath the crisp crust, this boule is ideal for those who like their toast to be fluffy. It stays remarkably fresh for several days too, but keep slices thin or you could end up with a heavy gut.

:: The Village Bakery Organic Rossisky Rye Bread, £1.77, Waitrose

Based on a sourdough from the Russian city of Kostroma on the Volga River, this traditional-style pure rye flour bread is dark and dense - and makes the perfect canvas for mashed avocado and prawns.

:: Morrisons Wheat, Spelt & Rye Bread, £1, Morrisons

Because of the mix of ingredients, this loaf isn't as heavy as some of the other breads made with pure rye flour. It's unsliced (and slices more easily than pure rye bread), with a superbly light, slightly chewy texture.