Why keeping a food log alone helps you control your weight

Marilia Coutinho & Antonio Bruno

We hate this title. We didn’t write it to trick you, though: we know you are concerned with your shape and the measurement tools available to you are the scale and the measuring tape. We also know that what bothers you is actually what you see in the mirror or the discomfort with your pants. Although we do believe that the underlying need for your concern is a decrease in body fat (or a change in body composition), and not weight, we’ll work with that.

Also, if you are an athlete who competes in a sport organized along bodyweight classes, then you are actually concerned with your weight.

That said, let’s talk about the food diary or log.


What research says about journaling

Research shows that there is a high correlation between successful dieting (and training!) and journaling. One study conducted by Johnson and Wardle (2011) measured the weight loss result of 2979 women and 642 men who joined a web-based food and exercise diary platform between 2005 and 2008. Their results show that among the overweight or obese members, those in the highest tertile of engagement with food diaries (vs the lowest) were more likely to achieve clinically significant (> 5%) weight loss (men: OR = 3.45 p < .001; women: OR = 5.05 p < .001). Wang and collaborators (2012) measured the results of journaling intervention on a group of obese patients in a rural community. The intervention group had significantly higher weight loss than the control group.

But how reliable are these journals? Much higher than self-reported memory-based accounts. In a study conducted by Lillegaard and Andersen (2007),  57% of the participants in a journaling study were classified as “acceptable reporters”, 39% as under-reporters and 4% as over-reporters.


Why journaling alone affects food habits and promotes weight loss

There are no studies addressing this specific question. Data show journaling affects food habits, though. Studies also show that much of our eating behavior is unconscious. Eating disorders are an extreme form of that, as an emotional strategy to escape self-awareness (Heatherton & Baumeister 1991). A study by Moynihan and collaborators (2015) shows that people eat unhealthy or “exciting” healthy food to escape awareness of boredom itself. The body of evidence suggesting that consumption of calorie dense food is an unconscious form of self-medication because it decreases cortisol levels points at the same direction (Appelhans 2010, Tomiyama 2012).

What we know about food behavior suggests that most of it is unconscious and automatic. And just like anything else, unhealthy behavior can be automatized as much as healthy behavior and action.

The problem is that we have little access to what we are doing according to an unconscious template. We keep moving wrong, acting wrong and eating wrong, or, rather, dysfunctionally. What journaling does is bring unconscious behavior to the conscious level, therefore providing a tool to change it.

It sounds simple, and it is: most serious eating issues don’t require highly complex diet strategies. As long as the individual is willing to be proactive and take control of his or her behavior, the journal is the instrument he or she needs to become aware of it. From then on, following professional advice or even common sense is much easier.


Appelhans BM. Circulating leptin moderates the effect of stress on snack intake independent of body mass . Eat Behav. 2010 Aug;11(3):152-5. doi: 10.1016/j.eatbeh.2010.01.004. Epub 2010 Jan 13.

Heatherton, Todd F., and Roy F. Baumeister. “Binge eating as escape from self-awareness.” Psychological bulletin 110.1 (1991): 86.

Johnson, Fiona, and Jane Wardle. “The association between weight loss and engagement with a web-based food and exercise diary in a commercial weight loss programme: a retrospective analysis.” International Journal of Behavioral Nutrition and Physical Activity 8.1 (2011): 1.

Lillegaard, I. T. L., and L. F. Andersen. “Validation of a pre-coded food diary with energy expenditure, comparison of under-reporters v. acceptable reporters.” British journal of nutrition 94.06 (2005): 998-1003.

Moynihan, Andrew B., et al. “Eaten up by boredom: consuming food to escape awareness of the bored self.” Frontiers in psychology 6 (2015).

Tomiyama AJ, Schamarek I, Lustig RH, Kirschbaum C, Puterman E, Havel PJ, Epel ES. Leptin concentrations in response to acute stress predict subsequent intake of comfort foods. Physiol Behav. 2012 Aug 20;107(1):34-9. doi: 10.1016/j.physbeh.2012.04.021. Epub 2012 May 2.

Wang, Chi-Jane, et al. “The efficacy of using self-monitoring diaries in a weight loss program for chronically ill obese adults in a rural area.” Journal of Nursing Research 20.3 (2012): 181-188.

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