Celeste Cooper usually reaches for a little packet of the blue stuff or the yellow stuff to sweeten her coffee or tea.

Sugar substitutes are known by the color of their individual packets. The blue stuff is aspartame -- Equal. The yellow stuff is sucralose -- Splenda.

"They taste about the same," said Cooper, a registered nurse and certified diabetes educator who has diabetes. Being able to have a sweet drink helps her feel less deprived.

"You don't feel like you are giving up anything; that is the goal," said Cooper, who works at St. Francis Medical Center in Chesterfield County.

Millions of Americans, while trying to lose weight or dealing with diabetes and watching their blood-sugar levels, turn to sugar substitutes to get the taste of sweetness.

The sugar substitute market is expanding, as is the competition for market share. Sweetener products sold for tabletop use are part of the product portfolio of sugar-substitute companies. The companies also compete to have their products in commercially produced foods.

With so much at stake, there has been a sweetener war of sorts going on.

The company that makes Equal sued the makers of Splenda over advertising that claimed Splenda was "made from sugar so it tastes like sugar." Since Splenda hit U.S. tabletops, it has grabbed significant market share from Equal. The parties agreed to settle the case last year but kept the terms secret.

The Sugar Association also sued Splenda's maker. Splenda has since modified its advertising to say "But it's not sugar," but the company has also countersued the Sugar Association, claiming a smear campaign.

Not to be left out, the Corn Refiners Association, tired of high-fructose corn syrup being badmouthed, has gone on the defensive with a television advertising campaign. Some have suggested that high-fructose corn syrup, a sweetener used in dozens of processed foods, is contributing to the obesity epidemic, not just in the U.S. but all over the world.

Added to the all the company bickering and posturing is the debate about the safety of artificial sweeteners, and whether, as one study suggested, sugar substitutes may promote weight gain.

So what's a consumer who just wants a little sweetness in morning coffee to do?

"Any form of sugar, whether it's corn syrup, high-fructose corn syrup, sugar, brown sugar, is certainly not helpful," said Lise Gloede, a registered dietitian and president-elect of the Virginia Dietetic Association. "We can document the negative effects on blood sugar, weight gain, cavities on the teeth; so any form of it really is something to look out for. You really have to look at all forms and be able to cut back on all forms."

As for the sugar substitutes -- don't overdo it.

"They are chemicals," said Gloede, who is in private practice in Northern Virginia. "You want to use them in moderation. . . . If you know you can't stop at one or two diet drinks, you need to be careful."

Cooper tells her clients not to be so focused on "sugar free" labels when evaluating foods.

"You've got to remember that with baked goods, it's not just the sugar. It's the carbohydrates," Cooper said. " If I am buying products in the store, I never buy sugar-free. Often, they really are the same, and the sugar-free products are much more expensive."

Dr. Scott Whitlow, a toxicologist and medical director of the Virginia Poison Center, said the center gets questions about the safety of sugar substitutes. Most want to know if they cause cancer.

"They do have some downsides. One of them is not long-term cancer," Whitlow said. "Most of the things you see touting how horrible they are for you are not legitimate scientific organizations."

In moderation, most sweetening products are OK, he said.

"It's almost impossible to get away from high-fructose corn syrup," Whitlow said. "No matter what you are ingesting, food or drink, anything in moderation is generally safe and not harmful. It's when we overdo it that we get ourselves in trouble."