Not so naughty, but still nice: Chefs are developing guilt-free desserts by replacing sugar with spice

It's every pudding lover's dream: a truly sumptuous dessert that won't ruin the waistline and won't up your odds of cardiac arrest. Amazingly, I think I may have found it. Agnar Sverrisson's signature dish – Valrhona white chocolate mousse, ice cream, dill and cucumber – is the kind of dessert I could write poetry about. I have been thinking about it repeatedly since I tasted it two days ago, at the Michelin-starred Texture in London. Half an hour after tasting, I stride into nearby Selfridges Food Hall to buy a big slab of Valrhona chocolate, in order, I hope, to relive the experience. No such luck. The next morning I am fighting the urge to march into the restaurant and order it for breakfast. I want to taste it again and again and again.

All this from a white chocolate ice cream and mousse that has been made with minimal sugar, no eggs or cream and contains ingredients more at home in a health-food store: sea weed, dill, pickled cucumber, rye bread and lemon. The result is a deliciously light and vivacious dessert, creamy and smooth but exploding with bursts of freshness and texture. Surprisingly, the white chocolate mousse is made with just white chocolate and water. Even more surprisingly, it is made by a Michelin-starred chef known for his healthy modern European food. His savoury dishes contain no cream or butter, he doesn't have a sweet tooth and refuses to have a pastry chef in his kitchen ("they use sugar all the time so get too used to the flavour").

"Everywhere I go I think desserts are too sweet," he says. "We just don't need to use that much sugar, we can get it from other sources. My desserts are not totally healthy. There will always be something that is not good for you, but by bringing in other ingredients, such as spices and vinegar, we can significantly reduce the sugar."

Icelandic Aggi Sverrisson is one of a growing number of chefs who are not just slaving away to produce fabulous, exciting food, but are also trying make it healthy. His repertoire of sugar-slashing tricks include bigging up the spices (ginger, lemon grass and lemon verbena) and using a fruit base so the fruit's natural sugar means you can drastically reduce the added sugar – that granulated stuff known as refined or table sugar. Vinegar is another favourite, swirled into his fruit soups (passion fruit and lemongrass, or strawberry, made with very little added sugar). "It minimises the sugar you need as it brings out the flavour. You need the best quality vinegar, however," he says.

Healthy puds, it seems, may well be the next big foodie trend. "So many people are becoming conscious of healthy eating, they are really looking for alternatives, but there are so many that people don't know about," says Claire Ptak, a former pastry chef from Berkeley restaurant Chez Panisse, renowned for its fresh, clean Californian cuisine. Together with Henry Dimbleby, co-founder of the quality fast-food chain Leon, Ptak has written a book about healthy desserts (Leon Baking and Pudding: Book Three) to help to spread the word.

Sugar, in particular, she says, is becoming less popular. A recent New York Times article branded sugar as "toxic", linking it not just with obesity and diabetes, but with heart disease, hypertension, and – somewhat controversially – even cancer.

The problem is that a healthy sugar alternative is hard to find: most healthy-leaning chefs shun the chemical kind and turn to natural sugars found in fruit and plants, though some sugar-haters say we still need to watch how much of these we consume.

Besides, can you really sacrifice refined sugar without losing flavour? "Yes," says Ptak. "We use agave nectar, a naturally occurring sugar, which gives a lovely flavour. Compared to refined sugar, it has a lower glycemic index and glycemic load [these are measures of how fast it raises your blood sugar]. And because it is sweeter than sugar, you don't use as much. It is not straightforward, however, because it is a liquid. For every 100g of sugar, you would use 70g of agave nectar, then reduce any liquid by 400ml."

Other alternatives include sunflower oil and coconut oil (instead of butter), which she says give cakes a lovely, soft texture. "Coconut oil is a superfood," she says, "but there are a lot of misconceptions because of its high saturated-fat content. But it is also good for you. It stores up so much energy in the body, so you feel full for longer." Chris Horridge, the director of the Fine Dining Academy, is another well-regarded chef who has long been beating the drum for healthy desserts.

When he first presented his gluten-free, dairy-free, sugar-free puds on the television programme Great British Menu three years ago, when he was head chef at the Michelin-starred Bath Priory Hotel, he wowed the judges but alienated a large swathe of the pudding-eating British public. "It is definitely possible to make healthy desserts that taste just as good," he says. "You can use gluten-free flour in most cases as you would normal flour, for example. We did an Opera Cake, which is a classic French sugar-rich dessert, with no dairy, no sugar, and made from gluten-free flour. We gave it to the pastry chef without telling him and he couldn't even taste any difference."

Horridge uses Xylito, a natural sugar substitute found in berries and oats. "It has a low GI and you can use it in the same way as sugar, except it won't caramelise." He won't let me in on the recipe for his highly convincing cream substitute but he does tell me how he makes nut milk, which, due to its fat, has the viscosity of milk: "Blitz up 250g almonds in a good blender with around 900ml spring water, then pass it through a fine cloth to remove the solids. The lovely nutty flavour works with bread-and-butter pudding, for example, but definitely not crème brûlée or vanilla ice cream." He also does a rice milk, by blitzing rice with water.

For Horridge, the main aim is not about calorie counting, but about providing food that people with certain conditions can eat – diabetics or people who are lactose intolerant, for example. Other chefs think that they almost have a duty of care to their customers. "Obesity is a national problem and everyone is becoming more health conscious," says Michelin-starred chef Sat Bains of Sat Bains Restaurant with Rooms. "We are in the business of serving food and in a tasting menu like ours, we have to watch the balance of flavours, including fat and sugar. It's not like a few years ago when you would leave a restaurant laden with cream and butter, feeling so full that you never want to think about food again. My perfect scenario is that people leave fresh and invigorated, savouring the memory of each dish."

Bains has spent the past six years reducing the sugar in his desserts, most notably in his ice cream, which he has cut from 240g sugar for 1 litre to 80g. "As long as you whip the egg yolk and sugar to the sabayon [the ribbon stage] so it still stabilises, it's amazing how little sugar you need. It's not just healthier, you end up with a purer, cleaner flavour." His advice to home cooks? "Try reducing the sugar or butter content by 25 per cent, whatever the recipe says, and see what happens. If you can't see any difference, stick with the new recipe."

Television chef Harry Eastwood, presenter of Cook Yourself Thin, also thinks that healthier ingredients can boost the quality of the pud, a belief that led her to launch Petit Pois, a range of vegetable-based cupcakes.

"I'm not some health nut," she says. "I'm just militant about good cake. The fact is that vegetables are fantastic for cake textures. They make them lighter, fluffier and maintain the perfect level of moisture so they last longer without any preservatives."

Sweet potatoes, butternut squash and parsnips, she says, are "full of natural sugars and starch and so we can cut down on added sugar and some of the flour." She also uses courgettes, turnips and suede. "Courgettes are a real winner. They make the cake lighter, fluff up and stabilise a cake mixture." Flavours include butternut squash and orange, courgette and lemon, and chocolate and beetroot. Two cakes, she says, contain enough vegetables to be "just shy of one of your five-a-day". She has also inched the sugar down from 170-180g to around 50g per 12 cup cakes "so it is still sweet enough to be a cake".

A week later, I receive a tupperware box of four Petit Pois cakes by courier; butternut squash and orange, with a thin layer of lemon icing. I give one to my boyfriend and eat two in one go. They are light, moist, fluffy and sweet and – no word of a lie – probably the best cupcakes I have ever had.

Healthy alternatives

Agave nectar: Beloved of the health-food movement, this naturally occurring sugar has a low glycemic index (GI) and load (GL). We are still advised to eat it in moderation, however, because of its high fructose content, which can be converted only in the liver. High levels are said to activate enzymes that turn the fructose into fat.

Vegetables in cake: Vegetables such as courgettes and butternut squash give a lighter, fresher moister texture when used in cakes.

Fruit: Using fruit as a base to a dessert gives a natural sweetness which counters the need to add extra sugar.

Gluten-free flour: can be used in the same way as normal flour. Spelt flour is unrefined and also low in gluten.

Coconut butter and oil: This can be used for cooking in the same way as butter. The oil gives cakes and pastries a lovely soft texture. Despite being lauded in natural food circles for its myriad health benefits, the Food Standards Agency cautions against eating too much because of high saturated-fat content.

Xylito: is a natural low-calorie alternative to table sugar. It has a low GI but can be used in all the same ways as refined sugar. Available in supermarkets.

'Sweet Freedom' This natural sweetener and syrup made from fruit and carob has 25 per cent fewer calories than sugar and a lower GL.

Nut milk: To replace dairy, blitz up 250g almonds in a good blender with around 900ml spring water, then pass it through a fine cloth to remove the solids. Do the same with rice.