HOW THEY STACK UP

1. Just Fresh Raspberry Fields Salad (mixed greens, blue cheese crumbles, walnuts, carrots, raisins and fat-free raspberry vinaigrette): 544 calories.

Wendy’s Apple Pecan Chicken Salad (lettuce, grilled chicken, blue cheese crumbles, pecans and pomegranate vinaigrette): 590 calories.

2. Olive Garden bread stick with garlic-butter spread: 140 calories.

Red Lobster Cheddar Bay biscuit: 160 calories.

3. Burger King Whopper With Cheese (with mayonnaise): 730 calories.

Jack in the Box Jumbo Jack With Cheese: 570 calories.

4. Dunkin’ Donuts Plain Glazed Doughnut (not cake): 260 calories.

Krispy Kreme Original Glazed: 190 calories.

5. Chipotle Sofritas (tofu) Burrito (with white rice, black beans, roasted corn salsa, lettuce and cheese): 935 calories.

Subway 6-inch Chicken and Bacon Ranch Melt (on nine-grain wheat bread with lettuce, tomatoes, onions, green peppers and cucumbers): 570 calories.

Sources: Company nutrition information, My Fitness Pal and www.nutritionix.com.

ABOUT CALORIES

What is a calorie?

It’s the amount of energy needed to raise the temperature of 1 kilogram of water by 1 degree Celsius.

What does that mean?

Calories come from plants or from animals that have eaten plants. Chlorophyll in plants absorbs energy from the sun and converts it to chemical energy. A calorie represents the amount of energy available to your muscle cells when you eat carbohydrates created by plants from carbon dioxide and water by capturing the energy of the sun.

What’s the trick?

Our bodies aren’t that efficient. We don’t consume or use all the calories we take in. Some are eliminated as waste and some are stored. If a lot are stored, they get converted into fat.

Are all calories alike?

While they are the same in theory, calories from foods that are higher in nutrients and fiber are used differently by your body than calories from foods that are higher in fat and sugar. A food that is higher in calories but provides more vitamins, nutrients and dietary fiber is better for you than a food that is lower in calories but has more sodium, fat or sugar or less fiber.

How many calories do you need?

Nutrition labels are based on 2,000 calories a day. But that’s the number needed by an active male. Women, children, smaller men and sedentary people need fewer. A 35-year-old woman who is 5-foot-6 and weighs 130 pounds and is lightly active 2 or 3 times a week needs 1,789 calories a day. Here’s a calculator that can help you check your needs: www.calculator.net.

If you eat out a lot, get ready to sharpen your math skills.

Calories are back. And you’re about to see a lot more about them.

Under new regulations from the Food & Drug Administration, restaurant chains and food services across the country have to add calorie counts to their menus by Nov. 1. That means you’ll soon start to see calorie counts on everything from your drive-through sandwich to your popcorn at the movies.

Nutritionists and dietitians are hailing the news as the biggest step forward in healthful-eating information since nutrition labels were added to food packages in the early 1990s.

Dr. Beth Racine, an associate professor of public health services at UNC Charlotte, calls it earth-shaking. “For the food-information transparency movement, it’s big.”

It’s also a huge amount of work that has some companies scrambling to comply. Under the FDA’s rules, restaurants with more than 20 locations will have to add the information to their menus, including drive-through displays and some vending machines.

And while single-location restaurants and small food businesses don’t have to add the information, they may find themselves under pressure to do it as customers start expecting to see more.

Displaying calories also may put pressure on big companies to offer more food that is lower in calories, says Racine.

“If Starbucks puts something in the window and it has 500 calories, they might be embarrassed, so maybe they’ll change it. They’re motivated to make improvements, which I think would be the best outcome. Even if (a consumer) doesn’t care, they’re still benefiting.”

While the restaurant business figures it all out, how do you use this new information? That’s where your math skills come in, says Marion Nestle, a professor at New York University who writes frequently about nutrition news.

To use the calorie information well, you have to know how that number fits into your daily diet. While 2,000 calories a day is a ballpark figure, that’s based on the needs of an average-size, active man. Your own calorie needs vary based on your age, gender, weight, height and physical activity.

“Menu labeling has a big effect on my choices,” Nestle said by email. “If people pay attention to the labeling, it could help them realize the one thing about calories that I wish everyone understood: Larger portions have more calories.”