Pros and Cons of Keeping a Diet Log

Keeping a diet log has some advantages but there may also be some pitfalls. Here's how to get the most out of a diet log.

Monica Reinagel, MS, LD/N, CNS
5-minute read
Episode #434

As a society, we’ve become sort of obsessed with gathering data about various health-related activities, like how many calories we take in, how many hours of sleep we get, and how many steps we take. Diet tracking apps, which allow you to log your food intake throughout the day, are among the most popular category of mobile apps. Chances are good that you’ve at least tried using an app like MyFitnessPal to track what you eat, perhaps in conjunction with an activity tracker like the Fitbit.  

There are a lot of potential advantages to keeping a diet log but also some possible pitfalls. Here are what I see as some of the main pros and cons of diet tracking

Advantages of keeping a diet log


Keeping a record of every single thing you eat definitely increases your awareness of your eating behavior. This is especially true if you tend to eat unconsciously or in response to external triggers.

People who commit to keeping a strict log are often amazed to realize how often they eat throughout the day. For example, you might estimate that you only eat once or twice between meals and be amazed to discover that you actually eat 6 or 7 times outside of mealtime.

Obviously, if you can’t even remember eating that Hershey’s kiss from the bowl on your coworker’s desk, you didn’t enjoy it that much.  And unconscious or mindless eating is a frequent source of excess calories.


Keeping a diet log also introduces a degree of accountability, even if it's only to yourself.  If you’re truly committed to writing down every bite, you might find yourself thinking twice about going back for that second bowl of ice cream, simply because you don’t want it staring back at you from your log at the end of the day.

The accountability factor is even more compelling if you are sharing your diet log with a trainer or coach or even with friends or strangers. Most of the diet tracking apps take full advantage of this by building in a lot of social features, where you can choose to share your log with others who are using the app or on your social media channels. The desire to keep up appearances seems to be extremely motivating for a lot of people.


Most diet trackers will also provide a certain amount of analysis about what you eat...some are quite detailed.  You can learn a lot of useful information this way, such as how much protein or calcium or sugar or sodium you typically consume. You can use this information to make adjustments if necessary. This can also be extremely useful information to share if you are working with a nutrition professional.

Although you can use a diet tracker to analyze and improve your diet choices, it really shouldn’t be necessary to do this forever. Although we usually express nutrition requirements on a per day basis, as in “1000 mg of calcium per day,” it’s not necessary to get exactly 1,000 mg of calcium every day. It’s fine if you get 800 today and 1100 tomorrow. The same is true of just about any nutrient you can think of. Although jenga-ing together a “perfect” day can be a fun little game, that degree of precision is really not necessary for good nutrition.

After a while, you should get the hang of which kinds of foods and meals add up to a complete and balanced diet, what sort of portion sizes are appropriate for your calorie needs, which foods you are better off avoiding all together,  and even how often you can afford to splurge on a treat.


And finally, keeping a detailed diet log can be a good way to figure out whether a food (or foods) could be responsible for symptoms such as headaches or sinus infections or digestive issues. The trick here is to keep track not only of what you eat but also keep a log of any symptoms you are experiencing. Sometimes, you (or your nutrition professional) can detect a pattern that might not be immediately obvious. It can also be used to rule out suspected causes.

You might also find behavioral insights in your diet log, such as the fact that having a couple of drinks with dinner increases how much food you consume over the course of the evening. Or that you tend to eat more at lunch after eating cereal for breakfast than you do if you eat eggs. You might discover that eating very little on one day leads you to overcompensate the next, resulting in a net increase in calories.  As they say, knowledge is power.

Potential Pitfalls of Diet Tracking

I have kept food diaries at various times, although never for more than a week or so. I have asked clients to keep them so that I could assess their diets and suggest changes, but only as a short term exercise in information gathering. Because I think there’s a potential downside to completely outsourcing our ability to make good choices about what and how much to eat.


About the Author

Monica Reinagel, MS, LD/N, CNS

Monica Reinagel is a board-certified licensed nutritionist, author, and the creator of one of iTunes' most highly ranked health and fitness podcasts. Her advice is regularly featured on the TODAY show, Dr. Oz, NPR, and in the nation's leading newspapers, magazines, and websites. Do you have a nutrition question? Call the Nutrition Diva listener line at 443-961-6206. Your question could be featured on the show.