Coffee shops can be as unhealthy as fast food chains and use misleading names to make their food seem less calorific, according to the Government’s top nutritionist.

Muffins with names such as “lemon and poppy seed” mislead customers into believing they are healthy and should come with bigger calorie content signs, Dr Alison Tedstone has suggested.

She said that while consumers understand that the main products in fast food chains can be highly calorific, in coffee shops “often you’ve got no idea”.

Muffins in high street coffee shops, such as Pret A Manger's Breakfast Muffins, contain ingredients normally associated with a healthy diet, like “pumpkin seed”, and can comprise more than 420 calories per 115g serving.

When coupled with milky coffees, such as the Starbucks large latte with whole milk, customers can walk away with a drink and a snack containing more than 700 calories.

By contrast the McDonald's Big Mac burger comprises roughly 540 calories. The fast food giant has included calorie labels in its restaurants since 2012.

“Coffee shops have got a long way to go,” said Dr Tedstone.

“So often it’s “would you like a coffee muffin with that, madam” and if the muffin’s got a lovely name that implies it’s healthy you don’t think about it in the same way you necessarily think about a burger,” she said.