“It’s Official: McDonald’s Highly Anticipated Chicken Big Mac Drops at U.S. Restaurants this Month,” proclaimed the chain’s press release announcing the limited-time menu item that made its debut on October 10. Here’s how the new chicken Big Mac compares to the beef original.

What’s in a Chicken Big Mac

“It’s Not Not a Big Mac,” says McDonald’s. True enough. McDonald’s didn’t exactly reinvent the wheel. The regular beef Big Mac and the chicken version have most of the same main ingredients:

• A white-flour “Big Mac” bun
• Processed cheese
• Big Mac sauce
• Pickles
• Lettuce

The chicken Big Mac subs in two “tempura battered chicken patties” in place of the usual two beef burger patties. The battered patties are crispy fried rounds of chicken, seasonings, and salt, breaded with white flour, corn flour, corn starch, wheat starch, salt, and a handful of other ingredients.

The chicken vs. beef Big Mac: Calories, carbs, red meat, and more

Patties aside, nearly identical ingredients mean that most of the unhealthy Nutrition Facts for a chicken or beef Big Mac are similar. And even their protein (25 grams) is no different.

Both Big Macs come in white-flour buns with no vegetables other than some token lettuce, pickles, and—on the burger—onions, so the fiber (2 to 3 grams) is low. The chicken patties’ seasoned “tempura battered” coating helps explain why the Chicken Big Mac has more calories (700 vs. 590), carbs (61 g vs. 46 g), and sodium (1,410 milligrams vs. 1,050 mg) than its beefy brother.

On the other hand, poultry instead of beef means the Chicken Big Mac has slightly less unhealthy saturated fat (8 g vs. 11 g) so it’s not as bad for your heart. And avoiding red meat means a lower risk of colorectal cancer. The International Agency for Research on Cancer has concluded that unprocessed red meats (like ground beef, patties, or steaks) are “probably carcinogenic.”

Learn more: Why are chicken and turkey healthier than lean beef and pork?

Here’s each Big Mac, by the numbers:

Ordering either Big Mac as a “meal” with a medium fries and Coke adds on 70 grams of sugar (about 17 teaspoons, or nearly 1½ days’ worth) and another 590 calories, bringing the total to 1,180 calories (beef) or 1,290 calories (chicken).

Another reason to ditch beef: climate change

With burgers, fries, and fried chicken nuggets and patties, nothing on McDonald’s menu is health food. But putting more chicken on the menu is better for avoiding an overheated Earth, which is a clear threat to our health and safety.

Beef damages the planet more than any other food. A 3 oz. serving of ground beef produces nearly 5 pounds’ worth of greenhouse gas emissions (in carbon dioxide equivalents)—far more than chicken, turkey, and pork (about 1 pound per serving), according to an Environmental Database compiled by the Harvard T.H. Chan School of Public Health.

In fact, replacing beef with plant-based proteins like beans, tofu, nuts, and plant-based meat is the most powerful way to lower the carbon footprint of your diet.

Hey McDonald’s, how about a Plant Big Mac in the U.S.?

Learn more: What foods create the most & least greenhouse gas emissions?

Both Big Macs are high in sodium. That’s no surprise.

An original beef Big Mac has 1,050 milligrams of sodium, nearly 50 percent of the 2,300 mg Daily Value (daily maximum) for adults.

The Chicken Big Mac is even saltier. Its 1,410 mg reaches roughly 60 percent of the DV. With the medium fries (260 mg) in a meal, you’re looking at 1,670 mg—that’s nearly three-quarters of the daily max!

But the Big Macs aren’t sodium standouts. Most restaurant food is high in sodium. When CSPI published a study that examined 91 top U.S. restaurant chains, many menu items exceeded the 2,300 mg daily max.

That helps explain why the average U.S. adult eats roughly 3,400 mg of sodium per day. Too much sodium increases blood pressure, and over time, the risk of heart attacks and strokes.

Learn more: How salty is too salty? A look at high-sodium menu items

What you can do about sodium in restaurant food

Thousands of consumers have already joined CSPI in calling for action from policymakers—and putting pressure on restaurant executives to lay off the salt. Join them! Take action by signing our petition to tell the restaurants with some of the saltiest menu items in the country to cut the salt.

In the meantime, you can protect your health: 

• Read our tips for spotting healthier restaurant foods
• Eat a heart-healthy diet with less sodium and more plant-based foods
• Stay active by finding an exercise habit you enjoy
• Read more about how to curb your risk of heart attacks and strokes

The bottom line on Big Macs

Chicken is a heart-healthier protein than beef, but McDonald's Chicken Big Mac has more white flour, calories, refined carbs, and sodium than a regular Big Mac. Neither is a healthy option, but chicken is less damaging to the planet.