Credit: Ian Thomas Jansen-Lonnquist.

What’s the most effective way to lose weight? Dieting and exercising are, of course, your bread and butter but it’s extremely easy to see no results because of lack of consistency. According to a new study, the people who were most successful at losing weight also wrote down everything they ate in a food journal. Although it might seem daunting at first, logging food only takes 15 minutes on average each day, and the results are well worth it.

For the study, researchers at the University of Vermont enlisted 142 people who had to self-monitor their calorie intake through a 6-month-long online weight control program. A certified dietitian managed a weekly online session for each group which followed the progress of the participants.

Over the course of the program, participants had to log their daily food intake. The food journal had to include the calories and fat for all foods and beverages they consumed, as well as the portion sizes and the preparation methods. The most successful study participant lost 10% of their body weight and spent 23.2 minutes each day self-monitoring their food intake during the first month of the program. By month 6, their average logging time had dropped down to only 14.6 minutes.

“People hate it; they think it’s onerous and awful, but the question we had was: How much time does dietary self-monitoring really take?” said Jean Harvey, chair of the Nutrition and Food Sciences Department at the University of Vermont and the lead author of the study. “The answer is, not very much.”

Surprisingly, individuals who took more time or included more details in their self-monitoring were not the most successful. Instead, the best predictor for meeting weight loss goal was the frequency of log-ins.

“Those who self-monitored three or more time per day, and were consistent day after day, were the most successful,” Harvey said. “It seems to be the act of self-monitoring itself that makes the difference – not the time spent or the details included.”

It’s encouraging that spending only 15 minutes per day on a food diary can lead to such a significant effect. After all, we’re all guilty of spending much more than that mindlessly scrolling through social media or other time-wasting activities. However, that’s not to say that it’s easy. You have to match the food you just ate with those from a database. You also have to weigh and measure the food, which can be challenging when eating out. Luckily there are various apps (i.e. LoseIt, Calorie King, and My Fitness Pal) that make this a lot easier, although even pen and paper work just fine. The act of keeping your accountable (and doing so frequently) is what matters.

“It’s highly effective, and it’s not as hard as people think,” Harvey said.

The findings were reported in the journal Obesity.