The striker said that "devastatingly" child food poverty is getting worse instead of better.
The three recommendations Rashford is supporting, part of Henry Dimbleby's National Food Strategy, aim to guarantee that every child at risk of going hungry gets some good food every day.
The first is to expand free school meal eligibility to all children aged 7-18 in all households earning £20,000 or less after benefits, and to children that are undocumented or living in immigrant households with "no recourse to public funds" (NRPF).
The second is to provide long-term funding for the Holiday Activities and Food Programme, increasing eligibility in line with free school meal expansion.
And the third is to expand Healthy Start eligibility to all households with pregnant women or children under five earning £20,000 or less after benefits, and invest in a communications campaign to increase uptake of the scheme which provides free vouchers to buy milk, fruit and vegetables.
Rashford is calling on the Government to urgently support the recommendations and include the funds needed in the Spending Review.
This follows his previous campaign, when more than 1.1 million people signed a petition on the parliamentary website.
New data from The Food Foundation shows that more UK households with children aged 17 and under are experiencing food insecurity than in the first wave of the pandemic.
A survey of 6,490 UK households found that 15% have experienced food insecurity in the past six months - levels that are approximately 27% higher than before the pandemic.
Rashford said: "Whilst we've come a long way in the last 20 months, placing the issue of child food poverty at the forefront, devastatingly, the issue is getting worse not better.
"The entire nation got behind the national team this summer so let's put these figures in football terms: You can fill 27 Wembley stadiums with the 2.5 million children that are struggling to know where their next meal might be coming from today.
"What is it going to take for these children to be prioritised? Instead of removing support through social security, we should be focusing efforts on developing a sustainable long-term road map out of this child hunger pandemic.
"I am, today, pledging my support for three recommendations from Part 2 of the National Food Strategy.
"I hope that we see the required investment pledged during the Autumn Spending Review.
"I will be writing to my MP about it, and I would encourage you all to do the same.
"It will take many of us to stand together on this, and show we care about reaching those most in need in our communities."
Speaking to Good Morning Britain on Monday, Mr Dimbleby said Rashford was an "amazing" voice for the cause, adding: "He's lived it.
"He can really talk to the experience and he gets rid of this idea that somehow this nanny state-ism or this is things that families should be able to do for themselves by painting a picture of what it's like to be in that situation."
Anna Taylor, executive director of The Food Foundation, said: "It's extremely distressing that now even more children lack a secure, nutritious diet compared with last year.
"Despite a sense of 'normality' returning, this is no time for complacency - we can't sit back and allow this damage to our children's health, learning and life chances, not to mention the heavy burden it bears on our NHS.
"We know children from deprived backgrounds have higher obesity rates, worse levels of diabetes, more tooth decay and even impaired height development, compared with their wealthier peers.
"This will only get worse if left unaddressed and entrench inequalities deeper. So, today, we are asking Government to act appropriately to protect our youngest citizens."
Rashford, 23, waged a high-profile campaign last year to persuade the Government to provide free meals to vulnerable youngsters in England throughout the school holidays during the coronavirus pandemic, forcing Prime Minister Boris Johnson into a U-turn.
He also became the youngest person to top the Sunday Times Giving List by raising £20 million in donations from supermarkets for groups tackling child poverty.
The #WriteNow campaign encourages the public to visit Rashford's campaign website endchildfoodpoverty.org/write-now and follow the steps to write to their local MP.