RFK Jr calls out popular chains over high-sugar coffee drinks: What's really in your cup?

Health and Human Service Secretary Robert F. Kennedy Jr. has taken aim at Starbucks and Dunkin' over sugar-loaded coffee drinks — but how much sugar do those drinks actually contain?

During an "Eat Real Food" rally in Austin, Texas, on Feb. 26, Kennedy referenced plans to challenge the two brands on the amount of sugar their iced coffee drinks contain.

"We're going to ask Dunkin' Donuts and Starbucks, 'Show us the safety data that show that it's OK for a teenage girl to drink an iced coffee with 115 grams of sugar in it,'" Kennedy said.

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"I don't think they're going to be able to do it."

Publicly available nutrition information shows that sugar totals vary widely depending on the drink and size ordered.

It appears that not all frozen coffees are created equal.

For example, the Starbucks website notes that a Grande Starbucks Frappuccino can have more than 45 grams of total sugar per drink — and that's not counting whipped cream and syrups. 

A Grande Caramel Starbucks Frappuccino has about 55 grams of sugar. 

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Dunkin' Frozen Coffees appear to have substantially more sugar than Starbucks drinks. A medium Caramel Crème Frozen Coffee has 132 grams of sugar, according to Dunkin' menus.

A medium Frozen Coffee with Cream has 81 grams of sugar — a high number considering its lack of added syrups.

On "Fox & Friends First" on Friday, family and emergency medicine physician Dr. Janette Nesheiwat said there was truth to Kennedy's concerns.

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"When you think about it, 100 grams of sugar — that's equivalent to about 25 teaspoons of sugar," she said.

"Think of 25 of those little cubes of sugar that you are putting in your drink. And really, many teenagers aren't aware of how much sugar they are consuming. That's why education is so important."

Excess sugar is extremely harmful "for your metabolism and increases your risk of chronic disease," Nesheiwat noted.

"We see obesity, diabetes, heart disease — and now we're seeing a lot of young patients with what we call non-alcoholic fatty liver disease," she said. 

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"And then, of course, let's not forget about the cavities that all the sugar can cause."

The sugar content in these drinks can easily exceed daily recommendations, said Mackenzie Burgess, a Los Angeles-based registered dietitian nutritionist and recipe developer at Cheerful Choices. 

"The American Heart Association suggests limiting added sugar to about 25 grams per day for women and 36 grams for men, yet many drinks contain far more than that," Burgess told Fox News Digital.

"For example, a medium Dunkin' Frozen Coffee has around 84 grams of added sugar, while a Grande Starbucks Caramel Ribbon Crunch Frappuccino has about 60 grams. That means one drink alone can have two to three times more sugar than recommended for the entire day."

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She compared a medium Dunkin' Frozen Coffee to three Snickers bars — and said most Frappuccinos "are comparable to a theater-size box of M&Ms.

"Another thing to keep in mind is that when you drink sugar instead of eating it, it often doesn't feel as filling, so it's easier to consume a large amount of sugar without realizing it," Burgess said. 

Some studies show that excess sugar can cause inflammation in the brain's memory, she said.

But the dietitian added that avoiding sugar doesn't mean you need to go without a pick-me-up.

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"As a dietitian, I always recommend starting with a base of unsweetened coffee and building from there," she said. "Choose iced coffee, cold brew or plain-brewed coffee first, then customize it."

Most major chains have sugar-free syrups and a multitude of milk options, including 2% and skim milk.

"Lately, I've enjoyed ordering a Grande Cold Brew with one pump of sugar-free vanilla, a splash of cream and cinnamon powder on top, which totals zero grams of added sugar," Burgess suggested.

Fox News Digital reached out to Starbucks and Dunkin' for comment.

Fox News Digital's Michael Sinkewicz contributed reporting.