Here's why your coffee habit is making you fat

Raising a glass (or mug) for National Coffee Day on Sunday could pose problems for your waistline.

American coffee consumption is up 5 percent this year, with 83 percent of adults drinking it, according to the National Coffee Association's 2013 National Coffee Drinking Trends report.

The difficulty, nutritionists say, is that only half of regular coffee drinkers are picking brewed coffee, consumption of which is down 7 percent from 2012.

"The old days of buying a cup of coffee and putting a packet of sugar in it are far behind us," said Jane Hurley, senior nutritionist for the Center for Science in the Public Interest.

Instead, 31 percent (about the same as last year) opt for gourmet drinks such as cappuccinos and lattes. Many go even fancier. A 2009 survey of orders in New York City by the Department of Health and Mental Hygiene found two-thirds of Starbucks customers and a quarter of Dunkin' Donuts customers picked blended coffee drinks, which use more milk, flavored syrups and whipped cream.

(Read more: Starbucks latte dries early pumpkin foods craze)

Those drinks pack a higher calorie count—on average 240 calories, versus 75 for brewed coffee with cream and sugar, said Pat Fiducia, chief executive for CalorieKing Publications, which tracks nutrition information for restaurant items. But many contain even more calories, sugar and fat.

A large Dunkin' Donuts Frozen Mocha Coffee Coolatta with Cream, for example, contains 1,050 calories, 53 grams of fat and 127 grams of sugar.

"In perspective, you have had more fat than you need for two days and more saturated fat than is healthy for a whole week," said Fiducia. It's also a little more than half the Food and Drug Administration's recommended 2,000 daily intake. And that sugar content? Translated into cooking measures, it's about two-thirds of a cup.

Coffee purveyors, for their part, say their menus are a response to customer preferences and offer a range of drinks—many of them with low calorie counts. A McDonald's spokeswoman said the company posts nutrition information for diners. Dunkin' Donuts has its DDSmart menu of "better-for-you items" including drinks and baked goods, said a spokeswoman. "Ultimately, we encourage our guests to make choices that are right for them," she said.

Many shops are taking other steps to lower calorie counts, making low- or nonfat milk the default choice, and adding sugar-free syrups, said Betsy Craig, chief executive of MenuTrinfo, which offers menu nutritional analysis for restaurants.

Consumers might take additional steps by picking a smaller size, and passing on the whipped cream and syrup, Hurley said.

A Starbucks spokeswoman said customers are encouraged to personalize orders. "As there are more than 170,000 different ways to customize a Starbucks beverage, customers can choose to lighten up their favorite beverage in a number of ways to save on calories," she said.

Seattle's Best Coffee encourages that, too. "You can always hold the whip, skip the cream and use nonfat milk for a lighter treat," said a spokeswoman.

Without such tweaks, some blended coffee drinks are heavy hitters. Click ahead to see seven that have among the highest calorie counts, according to nutritional data from the companies and CalorieKing.com:

—By CNBC's Kelli B. Grant. Follow her on Twitter @kelligrant.
Posted on 27 Sept. 2013.

32 ounces

Calories: 1,050

Fat: 53 grams

Sugar: 127 grams

32 ounces

Calories: 1,050

Fat: 52 grams

Sugar: 130 grams

20 ounces

Calories: 700

Fat: 26 grams

Sugar: 101 grams

22 ounces

Calories: 670

Fat: 50 grams

Sugar: 88 grams

24 ounces

Calories: 640

Fat: 22 grams

Sugar: 83 grams

24 ounces

Calories: 640

Fat: 23 grams

Sugar: 87 grams

20 ounces

Calories: 560

Fat: 18 grams

Sugar: 89 grams