When I told my students that I have been tracking what I eat, religiously and with the help of a food tracking app, for more than three years, the looks on their faces ranged from disbelief to something I perceived as pity (“she has nothing better to do?”).

I was introducing the food journaling concept to them. Basic nutrition classes, like the one I teach at Southern Maine Community College, frequently assign students to keep track of everything they eat or drink for three days and then analyze that information.

When I was in college, that meant looking up every food or ingredient in a big nutrient analysis book and doing lots of math to figure out each day’s nutrient and calorie totals. After that, we examined our results and strategized ways to improve our typical dietary intake.

The exercise is still a good one. Far from being “busy work,” keeping a food journal can be very helpful for improving diet quality and assisting with weight loss.

“Keeping track of one’s food intake helps people focus on their health goals, makes them more aware and keeps them honest about what they are eating,” says Amy Baker-Joyce, a registered and licensed dietitian who counsels clients at a Falmouth outpatient nutrition practice.

Multiple studies back up the efficacy of food journaling for weight loss assistance in particular. One 2012 study found that women who consistently used some type of food journal for the first six months of the yearlong study lost more weight (about 6 pounds more) than those who didn’t journal; even those who kept the journals for only 70 percent of the time lost more than the non-journaling study subjects.

Weight loss isn’t the only reason to track one’s food intake. Macronutrients – the carbs, protein and fat in foods – are easily monitored on food journaling apps and websites, where the information comes across in colorful graphs and charts.

A healthy balance of “macros” is the focus for 19-year-old Michaela Olsen. “For me, it’s less about reaching a certain calorie goal,” she said. “My goal is to lower my carb consumption and increase my protein to get a better balance. This is the most helpful function of my food app.”

Old-school food journaling, with a simple notebook and pencil, still has its place – especially for keeping track of simple things, like how many glasses of water you downed or how many servings of fruit and veggies you’ve eaten that day. But these days people are much more likely to get computerized assistance.

Websites like sparkpeople.com, myfooddiary.com and fitday.com offer users much more than a tracking mechanism. You’ll find a plethora of information and tools such as recipe nutrient analysis, exercise tracking, progress charting, tailored meal plans, goal setting and sometimes an online support community.

Many of these tools are free, though for additional perks like online coaching or consultations and support from a site’s registered dietitians, you’ll have to pay a monthly fee. (MyFoodDiary runs about $9 a month after a free trial week, and a SparkCoach costs the same, while around-the-clock online support and consultation with an actual registered dietitian on FitDay costs about $95/month.)

If you’re looking for a good-quality, free site that’s loaded with tools – but no coaching – check out the USDA’s SuperTracker site (supertracker.usda.gov).

Don’t want to be tied to your computer? Mobile apps are popular food tracking tools because they’re convenient, and many are free, too (though you’ll often be subject to in-app ads and upgrade prompts).

When Gorham resident Susan Graham-Rent noticed friends and family were using diet diaries and successfully losing weight, she started tracking her food and exercise on a phone app. She credits the LoseIt! (loseit.com) app with helping her reach her target weight several years ago, and she is going back to it now after noticing the scale inching upward following a broken leg and some health issues.

“My original goal with the app was to become accountable for my consumption and lose weight. It helped me to do that,” Graham-Rent said.

Using a food tracking app also is handy for giving yourself a diet checkup, especially if you feel you’re getting off track, dietitian Baker-Joyce said.

Despite the convenience of online and mobile food diet tracking options, people still face challenges using them. Entering foods into a daily diary can be tedious (it can be hard to find specific foods in the databases, for example, and entering information for a home-cooked recipe can be tricky).

Some apps now allow users to scan a food label’s barcode, which can make finding that food in the database easier, but this is handy mostly for more processed foods purchased at the market.

Accuracy can be problematic, too – your own and the database’s. People tend to make mistakes when estimating portion sizes they’ve consumed, so their daily food tally can be way off.

Errors are especially obvious in databases where users contribute information. Does your “one bowl” size match my bowls at home? Sometimes, they are overly optimistic, like saying 1 cup of homemade mac ‘n’ cheese – with hamburger added – contained just 250 calories.

What about eating out? Most apps are populated with information from typical chain and fast food restaurants, which is fine if you eat at those places, Graham-Rent says, “but not if you’re hitting up one of Portland’s wonderful restaurants.” In those situations, you may want to select simply prepared foods and do your best to estimate portion sizes when you enter items into the app.

Some people find that tracking their food intake in any way leads them to become focused on food in a way that feels obsessive and unpleasant. “I caution people about this,” Baker-Joyce said. But for many people, food journaling – on paper, a website or a smartphone – can provide a better awareness of food intake and a place from which to start making positive changes.

No matter how you decide to track your diet, Baker-Joyce says a consult with a registered dietitian can be useful if you have specific nutrition or health goals.

Kitty Broihier has been a registered, licensed dietitian for over 25 years. She holds a master’s degree in nutrition communications from Boston University and runs her consulting company, NutriComm Inc., from South Portland.