Washington ? So you picked up a 20-ounce soft drink with lunch — do you know how many calories you’re guzzling? A whopping 275, probably, although it can be hard to tell from the labels on today’s bottles.

That may change: The government asked food makers Friday to be more open about how much they pack into drinks, chips and other products Americans eat on the go, part of an effort to make it easier for consumers to count calories.

To keep trim, “calories in must equal calories out — it’s just that simple,” said Health and Human Services Secretary Tommy Thompson.

But counting calories can be confusing, he said in announcing some Food and Drug Administration recommendations designed to help.

Among the recommendations:

l Changing food labels to list calories in larger type, easier to see at a glance, and to list the percent of consumers’ daily allotment of calories a serving of each food brings. In the 20-ounce soft-drink example, those 275 calories would be 14 percent of a typical person’s daily allotment.

FDA wouldn’t say how soon it would propose regulations necessary for that change.

l Making packaged foods like chips and soft drinks, which most people eat all at once even though they contain two or more “servings,” list the product’s total calories. For example, 20-ounce soft drinks today are labeled as having 2 1/2 servings and 110 calories per serving.

FDA wrote food makers Friday urging they make that change immediately, although it’s not mandatory.

l Urging all restaurants to list calories on menus.