() Robert F. Kennedy Jr. on Wednesday wrapped up his three-day Make America Healthy Again tour in New Mexico, the state with the highest percentage of people on the country’s Supplemental Nutrition Assistance Program (SNAP).

Kennedy, the newly confirmed Health and Human Services secretary, and Brooke Rollins, the new agriculture secretary, have both signaled that they favor stripping sugary treats and ultra processed food from SNAP.

Kennedy has been most vocal, calling for the government to stop allowing the nearly $113 billion program that serves about 42 million Americans to use benefits to pay for “ soda or processed foods.”

But removing certain foods from SNAP known for years as food stamps isn’t as simple as it sounds.

The program is run by the USDA, not HHS, and is administered through individual states. It is authorized by the federal Food and Nutrition Act of 2008, which says SNAP benefits can be used for “any food or food product intended for human consumption,” except alcohol, tobacco and hot foods, including those prepared for immediate consumption.

From sugary cereals at breakfast to frozen pizzas at dinner, plus in-between snacks of potato chips, sodas and ice cream, ultra processed foods make up about 60% of the U.S. diet. For kids and teens, it’s even higher about two-thirds of what they eat.

Ultra processed foods have been linked to a host of negative health effects, from obesity and diabetes to heart disease, depression, dementia and more. One recent study suggested that eating these foods may raise the risk of early death.

Nutrition science is tricky, though, and most research so far has found connections, not proof, regarding the health consequences of these foods.

Food manufacturers argue that processing boosts food safety and supplies and offers a cheap, convenient way to provide a diverse and nutritious diet.

Even if the science were clear, it’s hard to know what practical advice to give when ultra processed foods account for what one study estimates is more than 70% of the U.S. food supply.

The Associated Press contributed to this report.