STEAK AND POTATOES is going the way of the ashtray; you're less and less likely to be offered either when you go to a dinner party. In the past 10 years, consumption of red meat has dropped 23 percent and of potatoes 13 percent. Breakfast habits have changed even more; Americans are eating far less bacon (down 31 percent) and far more natural cereal (up 57 percent). The use of pre-sweetened cereals has dropped 7 percent, eggs 16 percent, and even pancakes and french toast are down, all according to a summary of American food preferences compiled by Campbell Soup Co. The country is consuming less butter but a lot more cheese--53 percent more.

As for what Americans are drinking, cold beverages have increased, juices more than soft drinks but "ades" even more. Milk and coffee consumption have declined 15 percent, which fits with a Roper survey last July that found that 53 percent of the respondents were concerned about caffeine (66 percent about salt, 64 percent about the cholesterol in red meat, 58 percent about sugar). The Nestle' company's survey of business people found 62 percent of respondents consider coffee essential at breakfast, and only 7 percent never drink it.

But most intriguing are the habits surrounding these preferences. Only 10 percent of the coffee respondents have their first cup in bed; 6 percent drink it in the bathroom. And independence has taken hold to the point that only 26.6 percent report that they do not make their coffee, while at the office only 22.6 percent of the coffee is made by secretaries. In this bustling society it takes an average of 12.4 minutes to drink a cup--or rather a mug, which is the way most people drink it.

WHAT THE National Symphony would have us drink is a bottle of wine. More specifically, National Symphony Orchestra cabernet sauvignon and National Symphony Orchestra chardonnay. No, the Kennedy Center roof has not been turned over to grapevines; the orchestra has chosen two wines (Story Vineyards 1979 Cabernet Sauvignon and Mountain View Vineyards 1982 Chardonnay) to be bottled under its label and sold--at $80 a case--during its Radiothon broadcast March 3-6 on WGMS radio. One shudders to think of the new wine vocabulary this might cultivate ("After the crescendo of the bouquet, didn't you find the finish troppo allegro?")

AN APPLE a day may be followed by strawberries and pineapple, if 7-Up has its way. The company is test-marketing "fruit crisps" in Denver to see if freeze-dried sliced pineapple and strawberries in foil packets of 25 to 30 calories' worth might catch on as well as Weight Watchers' dried apple snacks.

SURELY you're not going to settle for such a dowdy Valentine gift as a box of chocolate. Any year you can get that. This year you can get a lollipop-built-for-two, a pair of lovebirds rendered in barley sugar. It's a big red, cherry-flavored, two-stick lollipop that weighs about a third of a pound and could keep a romantic couple intimately involved for a good long time. Costing $5.25 for 100 grams ($2.95 for 70 grams) at Food & Co., 1200 New Hampsire Ave. NW., it is as sweetly old-fashioned a lollipop as we have seen in many a Valentine's Day.