It is the sweet and sickly staple of many a French schoolchild's breakfast: la tartine de Nutella, a dollop of chocolate and hazelnut spread on a slice of baguette.

An estimated 235,000 tonnes of the paste – reportedly invented in the back room of an Italian pastry shop in 1944 – are consumed every year, around 100m pots in France alone.

Little wonder, then, that health warnings and government threats to impose a fat tax, known as the "Nutella amendment", have caused a mini revolution among Gallic consumers and sparked an international row.

On Monday, the Malaysian Palm Oil Council hit back at French claims that palm oil, a key ingredient in Nutella and widely used in margarine, biscuits and crisps, was detrimental to the environment and fuelling obesity. "Malaysia is deeply concerned with French Senator Yves Daudigny's proposed 300% tax increase on palm oil … Palm oil is a healthy, natural and important product, which 240,000 small farmers in Malaysia are proud to produce.

"Contrary to Senator Daudigny's comments, every nutritional and food expert concludes that palm oil is in fact free of dangerous trans fats, free of GMOs and contains valuable vitamins," the council's chief executive said in a statement.

Nutella's maker, Ferrero (of Ferrero Rocher chocolates fame), has also moved to reassure its customers in France, insisting that there will be no change in the recipe.

"Even if the tax is passed, we're not planning to change our recipe," Frédéric Thil, French director of the Italian company, told Le Parisien. He added that if the French went ahead with the increase, it would add at most six centimes to the price of a pot.

Nutella was first hit in 2010 by a broadside from the European Union that insisted jars of the spread would have to carry a health warning as it did not conform to the EU's "nutritional profile".

Nutella's main ingredients are sugar, milk powder, hazelnuts, cocoa, emulsifier, flavouring and palm oil, which is also used widely in margarine, biscuits and crisps.

France's Socialist government plans to quadruple taxes on products containing palm oil, arguing that its production is harmful to the environment and its consumption is fuelling obesity.

At present, palm oil is taxed at around €100 (£80) per metric tonne in France, but the government is proposing to raise this to €400. Around 20% of Nutella is palm oil.

The French government has already raised taxes on sugary drinks and is also proposing a tax hike on beer to help plug the hole in public finances and improve the nation's health.