WASHINGTON (WASHINGTON POST, REUTERS) - A fiery Michelle Obama vigorously defended her healthy eating initiative, her biggest legacy as first lady on Friday (May 12), telling a public health summit in Washington that something was "wrong" with an administration that did not want to give consumers nutrition information or teach children to eat healthily.

In a 43-minute conversation, peppered with sarcastic remarks and veiled references to the Trump administration, Michele Obama discussed topics from life since her husband left the presidency to her Let's Move! initiative.

"We gotta make sure we don't let anybody take us back," Obama said. "This is where you really have to look at motives, you know. You have to stop and think, why don't you want our kids to have good food at school? What is wrong with you? And why is that a partisan issue? Why would that be political? What is going on?"

The comments were her first public remarks after the Trump administration earlier this month relaxed rules that were aimed at making US school lunches healthier, moves seen by health advocates as a direct hit on her signature issue.

The moves have already seen the delay of rules meant to reduce sodium and refined grains in school lunches and provide calorie counts on restaurant menus. The former first lady championed many of those programs.

"Take me out of the equation - like me or don't like me," Obama added. "But think about why someone is OK with your kids eating crap. Why would you celebrate that? Why would you sit idly and be OK with that? Because here's the secret: If someone is doing that, they don't care about your kid."

The former first lady was speaking at the annual summit of the Partnership for a Healthier America, an organisation she helped found to extend her nutrition policies to the private sector. Her remarks were made during a conversation with Sam Kass, a longtime friend and the first executive director of her Let's Move! program.

Kass and Obama discussed a range of topics, including the Obamas' move to a new DC residence and the sorts of meals Obama ate as a child. On life since her husband's presidency, Obama said: "Being former is alright.")

But by far her most pointed comments were about the recent delays to the menu-labelling rules and the changes to the school lunch program.

The former first lady appeared to take issue with Agriculture Secretary Sonny Perdue's defence of the school lunch rollbacks, which he justified in part, in his May 1 announcement, by saying many kids didn't like the foods.

"That to me is one of the most ridiculous things that we talk about in this movement - 'the kids aren't happy,'" Obama said. "Well you know what? Kids don't like math either. What are we gonna do, stop teaching math?"

A spokesperson for the Department of Agriculture declined to comment on Obama's remarks, and said that "Sec. Perdue has nothing but the utmost respect for Michelle Obama."

Obama also objected to the proposed delay of new nutrition labels that were scheduled to go into effect in 2018. The new labels would feature information about calories and added sugars more prominently, but the packaged food industry has requested the compliance deadline be pushed back until at least 2020.

"Keep families ignorant. That's all I'm hearing," Obama said. "You don't need to know what's in your food. You can't handle that, mom. Just buy this, be quiet, spend your money - don't ask us about what's in your food."

The sharpness of Obama's remarks are unusual for a former first lady: There is an unwritten rule that they do not criticise their successors, said Kati Marton, the author of a best-selling book on presidential marriages. It's also a shift for Obama, who tended to tread cautiously during her husband's tenure.

But Marton said the rules, such as they are, were made for different times."It impossible to compare her to any prior first ladies, because it's impossible to compare the Trump administration to any prior one," she said. "I think it would be a mistake for the Obamas to play by rules that Trump doesn't play by, himself."

The past four months have seen the food industry seize onto President Donald Trump's anti-regulatory agenda, arguing for the delay or suspension of rules that Obama encouraged.

In recent weeks, the National Association of Convenience Stores, the National Grocers Association and the American Bakers Association have all cited the Trump administration's regulatory rollback as reason to delay the menu-labelling rules and new nutrition labels.

On April 27, the Food and Drug Administration announced its intention to delay the menu-labelling rules and take additional comment from industry.

Four days later, on May 1, Secretary Perdue told reporters at the Virginia elementary school that his department intended to delay planned sodium reductions in school meals and grant waivers for schools who said they couldn't meet higher whole-grain requirements.

At the time, Perdue praised the former first lady and her work on public health, and insisted his policies were not a "rollback." But it's clear, based on Obama and Kass' remarks on Friday, that they have not arrived at the same conclusion.

"We've already seen them try to ensure there's tons of salt, there's less whole grains," Kass said. "The core of our work is intact, but it makes no sense."

Obama's work on nutrition was often controversial during her husband's time in office. While her reforms to school meals were initially embraced by a bipartisan coalition of lawmakers, as well as the school-food industry and public health advocates, many conservatives and school-food workers bolted when they saw the extent of the new regulations.

Critics said that the former first lady overstepped her public role by becoming so involved in policy, and frequently panned measures like the school lunch standards as examples of government overreach. Some schools and parents accused the first lady of making school meals unpalatable for children, while imperilling the finances of cafeterias and increasing food waste.

But Obama was undeterred on Friday, making several joking references to "the nanny state." And the former first lady said that she and her husband planned to make children's health and nutrition a pillar of their future advocacy work, once they'd had some time to "breathe."

"You take your eye off the ball on things, you let other people determine what you're eating, what you're feeding, how you're moving - and before you know it your kids have type 2 diabetes and you're confused and shocked and hurt," Obama said.

In that situation, the former first lady added pointedly: "I hope you have healthcare."