Researchers compared 5 popular apps for calorie-counting, and the winner is clear

The Noom app doesn't show users their levels of micronutrients (like calcium, iron, and vitamin C) or macronutrients (carbs, protein, and fat), but its overall calorie estimates are pretty spot-on.

Noom is different from the other apps in its focus on wellness as opposed to traditional dieting. The app provides users with "coaches" who motivate them to meet their nutrition goals.

"Weight loss is a lot more than just writing things down," said Andreas Michaelides, Noom's chief psychology officer. "It's really about changing your behavior."

Unless someone has a clinical diagnosis and needs to track their micronutrients, he said, it's more important to form healthy, lifelong habits.

"Most people, without the assistance of a food database, would not be equipped to know the big picture," Michaelides said. "A lot of the calories in food are buried inside their meal."

Michaelides added that no nutrition app should tell people to consume extra calories because they've exercised. Tracking physical activity can help people set goals and learn new behaviors, but it shouldn't be a reason to change healthy eating patterns.

"People shouldn't be obsessed [with logging]," he said. "At the end of the day, it's really a matter of forming lifelong, sustainable habits."

FatSecret has been called "hands down the best calorie-counter app" by New York Magazine, but the recent study found that it significantly underestimates sodium and protein levels.

This could have serious consequences for people with high blood pressure who think they're consuming less sodium, the study said.

Similar to the Lose It! app, one issue with FatSecret is that it allows users to input their own food nutrition metrics, or select those that have been added by other users, which can result in inaccuracies.

A 2017 study identified MyFitnessPal as one of the top two nutrition apps recommended by dietitians. But the new study found that the app tends to underestimate micronutrients like calcium, iron, and vitamin C.

In addition to counting calories, MyFitnessPal users can track their water intake and macronutrients, giving them one of the most extensive nutrient databases of the five apps analyzed.

The National Academies of Sciences, Engineering, and Medicine recommends that women drink about 11.5 cups of water per day and men drink about 15.5 cups per day, but some of this water can come from food and other drinks.

S Health is the only app included in the recent study that doesn't have a barcode-scanning feature that allows users to scan an item's nutrition label. Instead, the app compares users' diets to nutritionist recommendations, and classifies them as either low, average, or high.

Like MyFitnessPal, the app significantly underestimates calcium, iron, and vitamin C levels in many foods, but gives accurate estimates for carbs and fat.