Trying to lose weight? Tracking what you eat in a smartphone app may help

By Sam Downing|

Pick up your phone. Open an app. Record what you've eaten today. This simple strategy may be enough to help you start losing weight, even without following a particular diet.

That's according to researchers from Duke University, who found that overweight and obese study participants lost about 2.5kg on average after three months (a clinically significant amount) just by regularly tracking food intake in the free app MyFitnessPal.

The study is published in the journal JMIR mHealth and uHealth.

Interestingly, the participants who just tracked their food intake lost almost as much weight as two other groups of participants: one only tracked their weight for a month, then switched to tracking their weight and food intake for remaining three; while the other tracked their weight and food intake for the whole period. These two groups also received nutrition guidance and feedback tailored to their progress via email.

The researchers had predicted that the additional weight-loss coaching would result in additional weight loss after three months — and were surprised it didn't.

But after six months, the group who had tracked their weight and food intake the whole time, as well as receiving the personalised coaching, had lost more weight on average than other participants. That suggests additional coaching would make a bigger difference over longer periods.

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"We have very strong evidence that consistent tracking — particularly of diet, but also one’s weight — is an essential element of successful weight loss,” said study co-author and Duke psychology professor Gary Bennett in a statement. "Consumers should look for apps that make it easy for them to track on a consistent basis."

The researchers noted that compliance was the key to success: in all three groups, participants who most frequently tracked their weight and food intake lost the most weight.

That mirrors the findings of another recent study published in the journal Obesity, in which set out to determine just how much time you have to spend tracking your food intake every day to successfully lose weight.

Researchers from the University of Vermont and the University of South Carolina pored over data from 142 overweight or obese people participating in a 24-week online weight control program, which involved daily food tracking, and weekly check-ins with a dietitian.

The most successful participants — those who lost more than 10 percent of their starting weight — spent about 15 minutes a day on average logging their food intake by the end of the program.

But it wasn't the total time that participants spent tracked their food intake that best predicted weight-loss success — it was how frequently they logged in to the website where they recorded what they'd eaten.

"Those who self-monitored three or more time per day, and were consistent day after day, were the most successful," said lead study author Jean Harvey, chair of the Nutrition and Food Sciences Department at the University of Vermont.


She concluded that dietary self-monitoring is "highly effective", and doesn't suck up as much time as people think.

Though tracking food will work for some, it won't work for everyone: some dietitians warn the practice can turn into an unhealthy obsession with counting every calorie. If that sounds like you, a better approach may be intuitive eating — which preaches eating what and when you like, while becoming more consciously aware of your thoughts and desires about food.

WW (the weight-loss program known until recently as Weight Watchers) encourages its followers to track their food intake via a system of "SmartPoints" allotted to everything they eat — nutritious foods have few or zero points, while less nutritious foods have many.

"The mere act of recording what you eat will evolve your eating habits," WW’s director of program and science, Dr Michelle Celander, told Coach.

She said it's a myth that, once you start tracking food intake, you have to continue doing so for the rest of your life to prevent future weight gain — only until you gain an understanding of what energy and nutrients are in what you're eating.

"In the beginning you need to pay attention [to what you eat], but as you learn what works for you you track less and less and less," she explained.

"You start with everyday life and then you layer in weekends and eating out — different situations that you need to learn to navigate. So after six months, nine months, you better understand every context of your life."

She added that you don't necessarily have to use an app or a food diary to stay mindful of how you're eating.

"We've all got phones. Take photos of what you've eaten and then reflect," she suggested. "But be diligent about taking a photo of everything you have."

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