Log What You Eat, Lose More Weight?

If you prefer: Bite it, write it.

That's the bottom line of two new studies that found that people who track their intake online or with a smartphone app do lose weight -- and that the task is not as tedious as people may think.

"It brings a mindfulness to what you are eating," says Jean Harvey, PhD, chair and professor of nutrition and food sciences at the University of Vermont, Burlington, and lead author of one recent study. Before digging into a rich dessert or a giant serving of french fries, people who track tend to think: "If I eat this, I have to write it down."

"We know that tracking is very difficult for people to do, but we also know the more you use an app, the more [weight] you lose," says Gary Bennett, PhD, a professor of psychology at Duke University and the co-author of another study.

The concept of tracking is not new for weight loss, of course, but an explosion of apps such as LoseIt, Calorie King, and MyFitnessPal has expanded the choices greatly, Harvey says.

Tracking With MyFitnessPal

In the Duke study, Bennett and his team randomly assigned 105 men and women, ages 21 to 65, to three groups, all using the free app version of MyFitnessPal. The company had no role in the study. For the study:

• One group tracked what they ate daily for 3 months.
• One group tracked their weight for a month, then began also logging food intake for the next 2 months. This group received weekly lessons about healthy eating, action plans, and feedback.
• A third group logged both weight and diet for all 3 months and got weekly lessons on healthy eating, action plans, and feedback.

No particular diet was suggested, but all were given advice about healthy eating and were asked to monitor what they ate.

All had a goal of losing 5% of their initial weight within 12 weeks, received a tailored daily calorie goal, and got automated reminders in the app. The researchers collected weight information in person at the start, 1 month, and 3 months; then by self-report 3 months after the study ended. During the study period, the researchers retrieved information from the app and from participants about their tracking habits.

On average, participants were age 42 with a body mass index (BMI) of nearly 32, which is considered obese. But the BMIs ranged from 25 to 45. At the 3 -month mark, 76 people remained in the study.

Tracking: What Works?

All three groups lost similar amounts of weight, Bennett says. Those who only tracked food lost about 5 pounds on average; those who tracked weight first and then added food tracking lost about 6; and those who did both for the entire 3 months lost a little over 6 on average. But some lost much more.

No one strategy outperformed the others as long as they were tracking, Bennett says.

When the researchers collected self-reports at the 6-month mark, after the study had ended, those who had tracked both weight and food for the entire 3-month study did keep off more weight. They had nearly a 7-pound average loss, while those in the weight-then-food group maintained a nearly 5-pound loss, and those in the app-only group averaged a little over 4 pounds.

"I think the real take-home point of this is, if you are using an app that you can download from the app store, you can lose a reasonable amount of weight in 6 months, just doing what they ask," Bennett says. "If you add a daily weigh-in, you might get a little more loss. What we are showing here is, you can get a reasonable amount of weight loss without getting a coach involved."  

In other words, the app-only group’s success showed that weight loss was possible even with no weekly lessons.

Tracking: Little Time Invested, Big Payoff?

In her study, Harvey focused on a big reason people don't track food intake: the complaint that it's too time-consuming.

She evaluated 142 men and women, on average age 49, with an average BMI of nearly 36, which is considered obese. After 6 months of tracking food intake, those most successful at weight loss spent less than 15 minutes a day logging food intake, down from a little over 23 minutes a day the first month of the study.

The researchers could look to see the frequency and intensity of the logins. "The people who were in and out of the website multiple times a day did better [at weight loss]," she says. "The number of minutes spent [recording intake] was not related to weight loss, but the frequency was."

Harvey looked more closely at the habits of her most successful participants, those who shed 10% of their start weight, and found they were consistent in their recording and they logged intake three or more times a day. That makes sense, she says, as the constant monitoring keeps you on track throughout the day, cutting the chances of overeating.

Tracking: Love It or Hate It?

Mention food logs, and the response is rarely neutral.

Liza Cornwall, 53, a Los Angeles corporate training manager, is a believer. "There are huge benefits to tracking," she says. From October 2018 to March 2019, she has tracked consistently as part of the WW (formerly Weight Watchers) program. And she's lost 35 pounds.

She does it throughout the day. "If you don't," she says, "you will forget."

Surprisingly, Bennett of Duke is a resister. He doesn't like food tracking, he admits, and doesn't do it. But he does track his weight daily. "That is the one thing I can be most consistent with," he says. And as his study shows, it works, too. So when he encounters the resisters, he tells them: "Yes, I am one; you just have to find something to stick with." If that's weight tracking, like he does, go for it.

Or, do the food tracking in your own style, he says. "I had a patient who resisted food tracking,'' he says. Instead of writing down every bite, ''she put a smiley face or a sad face on her day planner.'' She lost a lot of weight, he says. "We respond to data," he says, in whatever form that appeals to us.

Do some people resist due to shame about overeating? Maybe, but that can be addressed, Harvey says. "The approach we take is one of positive reinforcement for the [tracking] behavior rather than berating someone for their choices."

The key, Bennett says, is to ''track without judgment and to do so consistently. When people do that, they can quickly see the trends in their weight change, and realize that an uptick one day may change into a loss the next."

Take-Home Points

Consistency and frequency of tracking are important, Bennett and Harvey agree. "It makes more sense to write down what you are eating right after you eat it instead of at the end of the day," Harvey says. "If you wait until the end of the day and write down all your food, you can't ‘un-eat’ something," she says.

If you track constantly, you can observe that you ate too much for lunch, for instance, and should lighten up for dinner.

The format of tracking is less important than the tracking, Harvey say. "It can be something like the points WW uses, or it can be simply keeping track of food." Some count calories, others fat grams, for instance. Tracking becomes easier, Harvey says, since people tend to eat the same things often.

Tracking works because it holds dieters accountable, says Sharon Zarabi, bariatric program director at Lenox Hill Hospital, who reviewed the new research findings. "By tracking our food in an app, there is no denying any excess calories. Yes, it may be tedious. But you don't need to do it for the rest of your life." She finds tracking for even a week can give insight and help people make changes.

The self-monitoring works, Harvey says, ''unless you are comfortable consistently lying to yourself." And to those who have tried tracking and given up in frustration, Harvey says: "With the advent of more user-friendly apps, I would give it a shot again."

Bennett is on the scientific advisory board of Nutrisystem and Interactive Health and has equity in Coeus Health.