About 4.6 million children eat a packed lunch every day

Leaflets are to be given to schools, teachers and parents on what makes a nutritious packed lunch - such as wholegrain bread, fruit and yoghurts.

About 4.6 million children eat a packed lunch every day, but the government says many lunchboxes contain too much salt, sugar and saturated fat.

Figures suggest 25% of children may be obese and a diabetes risk by 2020.

We're not trying to patronise, we're trying to help Judy Hargadon, The School Food Trust

The efforts to improve nutrition in packed lunches follows similar moves over cooked meals.

Initiatives, such as hiring TV chef Jamie Oliver to revamp school menus, has seen the introduction of new guidelines.

In England, cooked meals must now include at least two portions of fruit and vegetables and deep-fried foods are restricted.

'More hot meals'

The School Food Trust, which works with the government, hopes to follow this up with its packed lunch leaflets and steer parents away from chocolate, crisps and fizzy drinks.

It suggests lunches should be made up of a variety of food from the four main food groups.

They should include:

The BBC's Breakfast programme has learned these leaflets will be distributed in the next few weeks.

According to the School Food Trust's chief executive, Judy Hargadon, it will help improve childrens' health.

"A simple leaflet that helps you talk to your children about it, that helps you have a dialogue with the school about it, is what we're trying to do," she said.

SANDWICH IDEAS Cheddar cheese with apple slices Cottage cheese and dried apricots Brie and cranberry sauce or jam Tuna, cucumber, green pepper, sweetcorn and tomato Mozzarella with grilled peppers The School Food Trust

"We're not trying to patronise, we're trying to help."

But Margaret Morrissey, of the National Confederation of Parent Teacher Associations (NCPTA), said the money should be spent on providing more hot meals for children.

"We are putting a lot of money into a leaflet when we should be making sure that schools can provide a hot lunch for children," she said.

"We are in danger of losing what for many children was the only hot meal they get to eat in a day."

Asked if any parents needed guidance on how to provide healthy lunches, she said: "I am sure that there will be some of them that do, but the majority of us have a pretty good idea of what our children want, need and like."