Muesli and strawberry porridge have joined bangers and beans in new Army ration packs developed by military catering chiefs in Bath.

The new 24-hour multi-climate ration packs have been designed to withstand extreme temperatures and provide a variety of meals to suit all tastes, including halal for Muslim soldiers, when personnel are away from base camp.

Gone are the brown biscuits and bully beef and in their place are cookies and Thai green curry meals, nutritionally balanced to provide troops with the minimum 4,000 calories a day they need.

The Ministry of Defence launched the 20 new menus along with 18 halal, vegetarian and Sikh and Hindu variations this week at the Defence Equipment and Support headquarters at Abbey Wood in Bristol. The new packs - put together by the DE&S catering team at Ensleigh in Bath - were sent to Afghanistan last week to be tried out by personnel across all the armed forces over the next three months.

The overhaul of the old packs began 18 months ago after soldiers complained there was not enough variety of food to encourage them to eat.

Lieutenant Commander Neil Horwood, project manager for operation ration packs, said the new menus had been drawn up with the help of soldiers who have recently returned from service in Afghanistan.

He said: "The problem with the old packs was duplication, which meant that if you were eating the same thing for four months, 80 per cent of the ration packs were the same – no one wants to eat baked beans for breakfast every day for four months.

"Now they have a choice between a cooked breakfast or a bowl of muesli which is nutritionally endorsed by the Surgeon General."

He added: "In an environment that will naturally suppress your appetite, we need to tempt troops to eat more.

"We have looked at what the Americans do but I think that, for the Brits, eating is much more of a social event rather than just a way to take fuel on board, so you have to look forward to your meal times."

Each ration pack has an 18-month shelf life and includes a mixture of dry foods and boil-in-the-bag pouches, as well as sachets of seasoning and tiny bottles of Tabasco sauce.

In the new packs there is also sweet salmon pasta, mixed bean salad, beef and cassava as well as Shrewsbury biscuits and stem ginger biscuits.

"The feedback so far from troops has been positive but I think the real test will be in three months' time when they have had a chance to really try them out," Lt Cdr Horwood said.

"I think 60 years ago it was bully beef and biscuits and to our parents a lasagne was adventurous.

"Now the 18-year-old soldier wants food that he could order from a takeaway on a Friday night, like chicken tikka masala, and we can now easily cater for a wide multi-cultural profile."

Major John Gilbert, 46, who has been in the army for 27 years, said the new rations were a huge improvement.

"When I first started, food was largely tinned which was extremely heavy to carry and there were only four different menus," he said.

"We used to have steak and kidney pudding which we called a baby's head because it was a thick suet crust with tiny bits of meat inside.

"The new ration packs are easy and light to carry, you can fold them over even when they are full and fit them into your pocket.

"It is so important to have variety because your appetite is suppressed by the climate, fatigue and stress and it is easy not to want to eat and then find yourself in a big calorie deficit.

"The food can provide a huge morale boost too because the simple act of getting the cooker on and getting hot food inside you makes life that little bit easier."

The new ration pack is comprised roughly of a third of the favourites from the old ration pack such as chocolate sponge, bacon, sausage and beans.

Maj Gilbert said: "They have kept the good aspects like the brew kit but they have also brought in more practical items like replacing chocolate, which either melts or freezes, with cereal bars.

"We have to take water from streams sometimes and the purification tablets make it taste like swimming pool water. The new packs have fruit tablets to make it better to drink."