Ministers are planning to ban Scottish schools from serving junk food and drinks at any time of day.
Ministers are seeking views on the proposed law
Education Minister Peter Peacock said the proposals would make nutritional standards statutory.
The Scottish Executive is inviting feedback on the proposed new law, under which councils would have to encourage more pupils to eat school meals.
Meanwhile, Holyrood officials conceded a school party should not have been given crisps on a visit on Wednesday.
A spokesman said that with hindsight it would have been more appropriate to stick to their usual snack choice of fruit.
Launching the proposed measures on junk food, Mr Peacock said councils may also be given new powers to provide free snacks to children during the school day.
He said local authorities did not currently have these powers.
"Those are the powers Mrs Thatcher took away, when she was famously described as Margaret Thatcher the Milk Snatcher," Mr Peacock said.
"This is opening the door potentially to the return of free milk in the middle of the morning, or free orange juice, or wider use of free breakfast."
EXECUTIVE PROPOSALS ON SCHOOL MEALS
Introducing new powers for councils to provide nutritious snacks
Ensuring that all food and drinks provided by schools meet nutritional standards
Offering parents advice on healthy packed lunches
Placing a duty on councils to promote uptake of free school meals for poorest families
Under the plans, local authorities would also come under pressure to ensure that healthy food is on offer in vending machines, tuck shops and breakfast clubs.
Campaigners are disappointed that there are no moves to provide all meals free.
At present, less than 50% of pupils eat school meals.
Education Minister Peter Peacock told BBC Radio's Good Morning Scotland programme: "One of the things we need to do is increase the take-up of the existing school meals entitlement.
"This will not just help those young people, but help their health into the long-term."
The executive's proposals would also encourage parents to think about nutrition, although there are no plans to inspect children's lunchboxes.
Figures published last year showed how obesity levels had risen among Scotland's children over a five-year period.
More than a third of 12-year-olds were overweight in the 2004/05 school year, while 19.4% were obese and 11.2% were classed as severely obese.
Mr Peacock said: "We are making the nutrient standards statutory so that we can ban things that are full of salt, or too full of fat or too full of sugar.
"There are also proposals there to make schools health-promoting environments. That is perhaps the most radical proposal.
"That is a very wide all-embracing concept of making sure that health is now a central purpose of schooling."
The consultation will run until 31 July, with a bill presented to parliament in the autumn.