The changes were first noticed by German consumer group Hamburg Consumer Protection Centre, which spotted a change in colour and compared the labels of old and new jars.
"As the colour of the new Nutella is lighter, we are working on the assumption that skimmed milk powder was added at the expense of cacao," it says.
And Ferrero, which makes Nutella, has admitted the change. It says that the quality of the spread has remained just as high - but chocolate fans are taking to social media to disagree.
"If the rumors of #Nutella changing their recipe are true, I am boycotting them," writes one; another adds: "Just heard that #Nutella changed their recipe. I mean come on there are things in life you CANT do! And this is one of this things!"
Other posters have expressed surprise that it's actually possible for Nutella to get any sweeter.
Cacao has recently become more expensive, which is presumably the reason for the change. And perhaps it's appropriate: after all, the spread was originally invented to make a small amount of cacao go as far as possible by mixing it with sugar and hazelnut paste.
Over the last year or so, chocolate fans have had to put up with a number of changes to their favourite products as the fall in the pound since the Brexit referendum has pushed up the price of ingredients.
Toblerone bars have shrunk, as have packets of Maltesers and Jaffa Cakes; meanwhile, Cadbury has been accused of changing the recipe of its Dairy Milk bars, although it denies this.
And Ferrero recently came under fire when the Hungarian food safety agency pointed out that the Nutella spread sold in Hungary appeared 'less creamy' than the version sold in Austria.
Britain's best foodie breaks
Britain's best foodie breaks
Combine beautiful British countryside with a bit of exercise on a bike tour of Carmarthenshire’s culture, sites and delicious cakes. The self-guided Cake Adventure Trails explore the coast and countryside via some of the finest tea shops, bakeries, delis and restaurants. The Great British Bike off Circular Route takes in National Route 47 via Wrights Food Emporium, Llanelli for lunch, afternoon tea at Whitford’s in Burry Port and gluten-free cake or scones at Burns Farm Shop at Kidwelly. Accommodation along the way includes Browns Hotel in Laugharne (from £95 per night) and The Cawdor in Llandeilo (from £65 per person per night).
Based in the fishermen's arches beside the Mayflower Steps, The Boathouse Café is just a stone's throw from Plymouth's historic Barbican and offers Fish ‘N’ Trips tours for families to have fun and learn more about the local marine environment while out on the water. After three hours of fishing, you will return to shore where children can relax with a well-earned hot chocolate and parents can kick back with a glass of wine or beer. Behind the scenes, the Boathouse Cafe staff fillet and cook your catch straight off the boat. Stay at the nearby Seymour Guesthouse from £62 per night.
In the beautiful South Devon countryside, you can spend an inspiring two days learning how to bake authentic artisan bread, plus the secret of fitting baking into even the craziest of lifestyles. Vidados' Bread baking short break combines a lesson for you to learn how to make a variety of breads, including pizza and sourdough. Your hosts will share all their knowledge about making beautiful, healthful organic breads, showing you how to use heritage flours and natural yeast cultures. The short break costs from £345 per person and includes a stay in a traditional cottage on the edge of Dartmoor.
Celebrity chef Raymond Blanc's Belmond Le Manoir aux Quat'Saisons was named the best hotel in the UK for 2016 by TripAdvisor and is a food lover's paradise. The upscale Oxfordshire hotel boasts a two Michelin star restaurant and invites guests to explore the beautiful gardens, learn kitchen tips and tricks from the masters in the daily courses at the Raymond Blanc Cookery School and indulge in wine and dine packages. Rooms start from £677 per night.
Luxury country house hotel Northcote is a wonderful place to escape for a gourmet break in Lancashire. An oasis for gourmands, the hotel has held a Michelin star for its restaurant since 1995 and boasts an interactive cookery school. Courses run throughout the year and range from Chinese cuisine to strawberries and cream. In the summer, you can get cooking with the BBQ Masterclass, which teaches you how to prepare for the ultimate barbecue dinner party, with lessons in marinating, butchering chicken and choosing the best accompaniments. The one-day course costs £195 per person. Rooms at Northcote are priced from £260 per night.
Hikers can get off-the-beaten track while feasting on delicious foodie delights along a 96-mile, long-distance trail of the West Highlands with Wilderness Scotland's interactive Food Guide to the West Highland Way. The classic trail stretches from Milngavie to Fort William, passing Loch Lomond, Rannoch Moor and Glencoe, while pinpointing the most delectable spots, from restaurants to pubs, breweries to distilleries and sweet-smelling bakeries - there are even recommendations for local fishing spots. The eight-night self-guided walking holiday costs from £695 per person, staying at hand-picked small hotels, guest houses and traditional B&Bs.
For a superb cook and catch experience in West Sussex, look no further than restaurant with rooms, the Crab & Lobster. Its authentic Catch and Cook fishing experience offers you the opportunity to haul in and later eat your own catch of the day. Local fisherman Dale Ford leads the full or half day adventure, offering you the chance to catch fish such as bass, rays, bream, tope, cod, whiting and congers. The excursion takes place on a working angling vessel and the fish is prepared by the restaurant's chefs. It costs £120 for a half day trip or £220 for a full day for up to four people. Stays at the Crab & Lobster start from £165 per night.
With its abundant kitchen garden, a Michelin-starred restaurant with a Hotel Chef of the Year and a variety of innovative courses at its cookery school, Lucknam Park offers the ultimate gourmet break in Wiltshire. The luxury hotel hosts a range of exciting courses, including street food masterclasses. The current American street food classes are influenced by Britain's love of US cuisine and cooks learn how to perfect the likes of the Philly cheese steak sandwich and pulled pork with honey coleslaw and crunchy tacos. The day course costs £175 per person. Stays at Lucknam Park start from £290 per night.
Visitors to Belfast can delve into the city's exciting food scene with the Belfast Food Tour, which takes you on a group or private trip to St George's Market and other food and drink highlights of Belfast, including a chocolate shop that teaches you the art of making chocolate and traditional Irish pubs where you will eat traditional Irish champ. The tour also takes you to explore the city's cobblestone streets and street art. It ends at Coppi, an amazing restaurant in Cathedral Quarter that serves up local meats, cheeses and Prosecco. The tour costs £45 per person including all food and drink. Stay at the nearby Malmaison, which offers a cocktail bar and restaurant serving a traditional Ulster Fry for breakfast, from £95 per night.
Led by reigning champion of MasterChef: The Professionals, Mark Stinchcombe and his wife Sue Stinchcombe, the Restaurant at Worcestershire's Eckington Manor hosts a series of evenings that revive Mark's TV tastes, where you can relish a six-course taster menu of dishes that have only been tasted by MasterChef judges Gregg Wallace, the double Michelin-starred chef Marcus Wareing and chef Monica Galetti. Mark's recreated dishes include scallops, roasted lemon, peas and buttermilk, and fillet of beef, marrow bone crusted short rib, carrots and charcoal emulsion. The break costs from £299 per couple and includes an overnight stay in one of Eckington Manor's boutique bedrooms.