7 Reasons Why You’re Underestimating Your Calorie Intake

Kristina LaRue, RD, CSSD, LDN
by Kristina LaRue, RD, CSSD, LDN
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7 Reasons Why You’re Underestimating Your Calorie Intake

Calories in, calories out. Oh, if it were only that simple. The good news is, there’s more to it than math. Figuring out how many calories you’re consuming isn’t an easy feat. In fact, people who struggle with their weight tend to underestimate their calorie intake by 40% compared to people of normal weight, who underestimate how much they eat by an average of 20%. Let’s take a deeper look into the reasons you might be underestimating your calorie intake.


A tablespoon of peanut butter is roughly 100 calories, but you could be off by 50 calories or more if you serve yourself up a heaping tablespoon or two. You can see how the calories can add up over the course of the day. Even trained bartenders get standard drinks wrong, and overpour. It’s hard to know how much you’re eating unless you’re actually measuring it. And let’s be honest: Who’s got the time or patience for that? Being meticulous about portions has pros and cons, and for some, it can lead to an unhealthy relationship with food and disordered eating.


Tracking apps like MyFitnessPal make calorie counting easier, if you know how to use them properly. But if you don’t record the right portion size or select a different brand than you actually consumed, you may be off with your counting. Using the barcode scanner and recipe function within the app makes your calorie counting more accurate.



Ready for your mind to be blown? Just because the nutrition information on a bag of chips says it contains 140 calories per serving, that doesn’t mean it actually has 140 calories in it. According the FDA labeling laws, a 20% margin of error is allowed in regards to calories, sugars, total fat, saturated fat, cholesterol and sodium. Thus that bag of chips may actually contain 168 calories and it would still be in compliance with the law. The secret’s out, folks.


If you’re eating out and relying on restaurants to be accurate when they post calories on the menu, good luck! In most cases, those are lowball estimates, especially if you’re eating the “healthy” options at a sitdown restaurant. The average American eats at least one meal outside of the home every day, which means we’re likely eating north of 100 calories more than we think we’re consuming. Fast-food chains tend to have more accurate calorie counts since everything is more standardized, pre-made and heat-and-serve, which leaves less room for human error or recipe adjustments. But we all know that’s not necessarily the best fuel for your body anyway.


We’re so busy that we eat on the go and have snacks at the ready, which means we often forget what we ate. We can be so distracted during our day that we forget to track that handful of almonds we ate during our meeting.

Those little nibbles can add up to 300 or more calories per day and you wouldn’t even know it.


Not the bacon, lettuce and tomato sandwich — rather the little bites, licks and tastes we’re probably all guilty of while prepping a meal, packing the kids’ lunchboxes or putting leftovers from dinner away. Those little nibbles can add up to 300 or more calories per day and you wouldn’t even know it.


I see this often in practice. Clients eat very scheduled and super clean from their meal prep madness during the week and then stop tracking on the weekends. We all need a little time off, right? And we like to go out and be social on the weekend, which often leads to eating out and celebrating with adult beverages. Being too strict during the week can give you a false sense of the average calories you’re actually consuming throughout the week, which in fact does include the weekend splurge.

While calorie counting can be a helpful tool for weight loss, it shouldn’t be the end all, be all and is actually most helpful if used as a guide. Calorie counting is a tool that provides insights into your dietary habits and preferences and allows you to learn to be a confident, balanced and intuitive eater. When tracking your food intake, notice more than the calories — how many protein, carbs and fats are you eating? Are your meals balanced in size or are you skipping and overeating? How many cups of vegetables are you eating a day?

Remember, too, that whole, unprocessed and nutrient-dense foods should make up the base of your diet, and they often don’t come with a nutrition facts panel. Because most of us tend to underestimate our calorie intake due to labeling variances, portion distortion and the like, take the holistic route by balancing your plate with whole foods to naturally keep your calories in check.

About the Author

Kristina LaRue, RD, CSSD, LDN
Kristina LaRue, RD, CSSD, LDN

Kristina is a board certified sports dietitian located in Orlando, Florida where she specializes in intuitive and mindful eating. She is the author of the food and nutrition blog, Love & Zest where she shares {mostly} healthy recipes with simple ingredients that are meant for real life. As a new mom, she knows that eating well and living an active lifestyle isn’t always easy… but it’s always worth it!! Kristina loves spending time outdoors with her family, sweaty workouts, and a good cup of coffee. Get in touch with her for one-on-one nutrition coaching (virtually or in person), or connect with her on PinterestInstagramFacebook  and YouTube.


8 responses to “7 Reasons Why You’re Underestimating Your Calorie Intake”

  1. Avatar Sara White says:

    Excellent article! 🙂 Thank you for posting this information! Lots of things people don’t always think about, but make a big difference.

  2. Avatar Amy Harney says:

    Thank you for this post. so informative.

  3. Avatar Afton says:

    This is something I realized a long time ago which is why I measured every little thing I ate in grams on a food scale. Absolutely everything in the old app I used could be logged to the exact gram, but unfortunately the app was canceled? Taken down? Whatever….it’s gone. I’m pretty disappointed in all the other calorie counting apps, including this one which seems to be my best option (now) because most foods don’t have the option to log in grams and even if they do you can only log up to 99 7/8 grams!!! I really wish MyFitnessPal would fix this. It seems like an obvious problem to me!!!

    • Avatar zachary webb says:

      If you change it from fractions to decimal you can key in upto 9999 servings. It’s a much better way than trying to get close with stupid fractions.

  4. Avatar robinbishop34 says:

    A general rule is for restaurant food, add 20%; for processed food, add 10%. So if Stake n’ Shake says their double steak burger is 300 calories, add 20% of 300 to the total for 360 calories. If a Lean Cuisine meal says 200 calories, add 10% for a total of 220.

    It is also important to track EVERYTHING. I track Omega 3 supplements, sugarless gum, condiments…everything! This sounds tedious, but it is in fact very easy. After just a few weeks of tracking, you will accumulate a log of things you eat most often that you can use forever. NOTE: There is NO such thing as a “free” food, or any other gimmicky, “scientific” explanation that can make one believe the calories in blueberries and kale are any different than calories in a deep fried doughnuts and ice cream. Besides, if you accurately and honestly adhere to your calorie and macro threshold, you’ll be eating very little of the latter –but you CAN have them if they fit in your limits.

    Scanning/interpreting food labels will become instinctual. Most people think figuring and tracking macros requires a degree in mathematics, and hours of time… this is total nonsense. Get started and track for about six weeks minimum (especially for women) to gauge fat loss. Weigh yourself everyday of the week for one week per month. Use the average of those seven days as your weight… do not get on the scale every day and fret over daily ups and downs.

    If you’re losing more than 2lbs a week, up your calories a bit; if you’re losing less than 1lb a week, decrease calories a bit. Repeat the next month. If you are considerably overweight it is okay to lose a little more than 2 a week as your body is much more likely to burn fat as fuel. As you approach your goal weight, you will want to decrease your deficit as you WILL metabolize muscle as fuel if rapidly losing.

    Now.. go buy a digital scale that weighs in grams. Grab a notebook, pen, and calculator and get started.

  5. Avatar itsjustmyreaction says:

    Thanks for sharing this great information

  6. Avatar vermillionlove says:

    I just wonder if I may be underestimating by not being sure what my TDEE/BMSR actually is. when asked about my activity level i’m unsure if I should say lightly active or sedentary.

  7. Avatar Cathy O says:

    Watch your nibbles! If you’re like me and you cook all your meals at home, a taste here and there to adjust the pot means you’re consuming calories even when you are not ready to eat yet!

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