As far as bad habits go, a morning cup of coffee probably isn't topping the list of those negatively affecting your health.
"Caffeine is controversial, but there isn't any definitive collection of studies to show it is harmful. A lot of people are making a bigger issue than is there," said Rod Hansen, associate professor of nutrition at Weber State University.
Ogden Regional Medical Center registered dietitian Rina Jordan agrees -- as long as caffeine consumption is moderate.
"Three cups of coffee or an equivalent doesn't change anything," she said.
Although Joy Musselman, registered dietitian with McKay-Dee Hospital, recommends fewer than 200 milligrams of caffeine -- the amount in one or two cups of coffee -- a day, her Ogden Regional Medical Center counterpart Katie Wewer said most healthy people can have as much as 400 milligrams of caffeine without any side effects.
And they may see a benefit of increased alertness, more athletic endurance and a higher metabolism.
What to watch for
In large part, according to the experts we talked to, it boils down to the individual response to caffeine.
"Everyone has different sensitivity," said Musselman. Negative side effects can occur with more or less than 200 milligrams of caffeine, depending on the person, she said.
Hansen agreed: "The overall issue is how it affects people. You know whether you are getting too much if it bothers you."
After two cups of coffee, you may get symptoms like jitteriness, headaches or insomnia, according to Musselman.
If so, you might want to reduce or avoid caffeine.
"I work with people with eating disorders and with kids at Job Corps. The kids drink caffeinated soda at every meal and wonder why they can't sleep," said Charlotte Scott, registered dietitian at McKay-Dee Hospital "They have a lot of anxiety and drink tons of Diet Coke and wonder why they are so stressed. Some are so stressed, they have to take medication to sleep. How easy would it be to just get rid of the (caffeine)?"
Those with heart problems should avoid caffeine, Wewer said, because it makes the heart beat faster; those with high blood pressure or who are pregnant should talk to a doctor about whether caffeine is safe for them.
You may also need to be careful about when you are drinking caffeine, according to Wewer.
"Be careful if you have problems sleeping. Drink (caffeine) before noon, and definitely before 4 p.m. Have a cup or two in the morning, and let it wear off so you can sleep at night," she said.
A cautionary view
Grant Cefalo, registered dietitian at McKay-Dee Hosptial, disagrees that small amounts of caffeine are harmless.
Dependency on caffeine can start at 100 milligrams a day, he said, resulting in side effects like headache, nausea, fatigue, moodiness or fuzziness if you stop drinking it.
"If you drink two Pepsis a day, you could be dependent on it. ... Theoretically, if you drink a cup of coffee a day, you could be dependent," he said. "Caffeine is the most consumed stimulant in the world, and the long-term effects are not known."
Side effects like dehydration, headaches, anxiety and insomnia can occur in those drinking more than 500 milligrams of caffeine a day, added Wewer.
Energy drinks have become a common way for people to consume caffeine.
Jordan said drinking one energy drink a day is probably OK, but such drinks tend to be abused, especially by young people.
"Kids are drinking tremendous amounts and it's tremendously problematic," she said.
Wewer said such drinks have up to 400 milligrams of caffeine per can -- plus other ingredients like guarana, ginseng and taurine that increase its effectiveness.
Cefalo adds that kids who drink energy drinks are more likely to drink alcohol and become intoxicated more easily when the two are mixed.
Jordan said it is the combination of alcohol as a depressant and an energy drink as a stimulant that is dangerous.
"It makes them feel good, so they drink more alcohol and get severely intoxicated and end up in ER," Cefalo said.
Hansen recommends that kids abstain from energy drinks and get more sleep and water.
Wewer extends that recommendation to adults:
"The recommendation of 200-300 milligrams of caffeine is just fine for most. Most healthy people can have up to 400 milligrams and it will not be a problem," she said, "but energy drinks don't have a place in anyone's diet."
HOW MUCH CAFFEINE?
* Coffee (8 ounces) -- 100-200 milligrams, depending on brand
* Espresso (1 ounce) -- 58-75 milligrams
* Latte (16 ounces) -- 150 milligrams
* Black tea (8 ounces) -- 40-120 milligrams
* Cola (12 ounces) -- 35-47 milligrams
* Mountain Dew (12 ounces) -- 54 milligrams
* Red Bull (8.3 ounces) -- 76 milligrams
* Hershey's Special Dark chocolate bar (1.45 ounces) -- 31 milligrams
Source: Mayo Clinic website