Why Net Calories Suck and Your My Fitness Pal APP is Failing You

net calories by David Greenwalt

Lots of people use diet and activity trackers such as My Fitness Pal to log their food intake and exercise. After all, there’s an old saying that “you can’t manage what you don’t measure.” And yet it seems to be backfiring.

From the first I got my hands on the slick, food-logging apps like My Fitness Pal, Loseit and more I noticed something right away that bothered me – net calories.

As a 20+ year wellness coach I laughed, but truly in a disgusted way, when I saw what they were doing. I thought “You’ve got to be kidding me! You’re letting people do THAT?” You see, I know the way the obese and overweight think. Add to that the every-human tendency to take a mile when given an inch? Get ready for disappointment on the scale.

The Problem With Net Calories

Here’s how these trackers work: You start every day with a certain number of calories to spend. That number is based on your height, weight, age, sex, activity level, and your goals — that is, whether you’re trying to lose, gain, or maintain your current weight.

Calories are subtracted from your balance as you log your meals into the diet tracker over the course of the day. Ideally, you don’t get to zero too early in the day. But if you do, there’s a solution. Let’s say it’s 5 p.m. and I’m down to my last 400 calories. But wait! I can take an evening run, log it into the app and now I’ve got 840 calories to spend on dinner! How awesome is that?

The general principle here is sound: The more you move, the more you can eat. In practice, however, these “net calorie” calculations are inaccurate and misleading — and they are suckering people into eating too many calories.

Although diet tracking apps can help you get an accurate picture of your calorie intake, they are much less reliable in determining how many calories you burn. Here are three ways they tend to get it wrong.

Problem 1 – You WILL Overassess Your Baseline Activity

In order to calculate your baseline calorie requirements, you indicate your activity level: sedentary, lightly active, moderately active, or very active. This does not refer to how much you exercise — we’ll get to that in a moment. This is just about your daily activity level. And guess what? Most people select an activity level that’s one or two categories higher than their lifestyle actually warrants. Unless you rope cattle 8 hours a day, your lifestyle probably does not qualify as “very active.”

If you use a wearable fitness tracker like a Fitbit or Jawbone or even a low-tech pedometer or step counter, you can use that to help you select the proper category for your lifestyle.

  • Fewer than 1,000 steps a day is sedentary.
  • 1,000 to 10,000 steps or about 4 miles a day is Lightly Active.
  • 10,000 to 23,000 steps or 4 to 10 miles a day is considered Active.
  • More than 23,000 steps or 10 miles a day is Highly active.

If you walk or run for exercise, you can count those steps and/or miles toward your baseline activity level if you want, but then you can’t enter them again as exercise. They’ve already been counted.

Problem 2 – You Over-estimate the Value of Additional Activity

You can use your diet tracking app to log other types of physical activities and exercise, such as a spinning class or yard work or ballroom dancing. However, you may not be burning anywhere near as many calories as it says you are. As with the readouts on the aerobic equipment at your gym, diet trackers may overestimate calories burned by anywhere from 10 to 25 percent. If you’re using those overly optimistic estimates to justify an extra dessert, you’re kidding yourself.

Problem 3 – You’re Counting Calories Burned Twice

If I spend the next hour sitting at my desk, I’ll burn about 100 calories. Those non-active calories are already accounted for in my daily calorie allowance. If I spent the next hour on the stationary bike instead, I’d burn 500 calories. That’s 400 more calories than I would have burned sitting at my desk.

But if I log my time on the bike into my diet tracker, it doesn’t add 400 calories to my total allowance… it adds 500. Essentially, it counts those 100 baseline calories twice.

The more activities you enter in to your exercise diary, the more this double-dipping error compounds — especially if you’re logging a lot of low-intensity activities like housecleaning or yoga.

I once heard from a woman who said she burned 3,000 calories a day. She was only eating 2,500. She couldn’t figure out why she was gaining weight. Sure enough, she was using an app to track her food intake and exercise.

According to MFP, her baseline calorie needs were about 1,800 calories a day. She then logged activities for almost every hour of her day: making beds, folding laundry, unloading the dishwasher, yoga class, walking the dog, grocery shopping, weeding the garden, playing the piano, cooking dinner, and so on. According to her tracker, all those activities were burning an extra 1200 calories a day — which gave her a total “net calorie” allowance of 3,000 calories a day. She figured she could eat 2,500 calories a day and still lose weight.

In reality, all of her routine activities probably only burned a couple hundred calories above and beyond her baseline. Instead of eating 500 calories less than she burned each day, she was really eating 500 calories more than she burned each day. No wonder she wasn’t losing weight.

Problem 4 – Logging Non-Exercise Activities – Stop it!

At Leanness Lifestyle University (LLU) we don’t allow our students to log laundry, unloading the dishwasher, gardening etc – everyday household activities. Why? See problem 3 for starters. Beyond this the reason is we know if you give people that “inch” they WILL take a “mile.” We all do this when we’re working on hard goals we suck at, especially ones that involved an addiction which more times than not is the case with the obese (of which I used to be – obese).

A second reason we don’t allow the logging of NON-exercise movement is because we feel it’s already been accounted for in the BASELINE ACTIVITY and metabolic rate calculations. We assume you are doing laundry, unloading the dishwasher (a.k.a – living) and MOST people who are struggling with their weight just do NOT have an ACTIVE or VERY ACTIVE lifestyle. And if I’m wrong? So be it – I’ve errored on the side of caution – my client won’t lose weight slower – they’ll lose weight faster and we can ALWAYS adjust calories up if we’re losing too fast.

So at LLU we only allow the logging of activity, that causes some level of sweat, performed intentionally, for the purpose of improving physical fitness (i.e., walking, strength training, all forms of intentional cardio etc)

David Says

I could tell you tips and tricks or, oh ya, I need to use that newfangled “HACK” word here – I could teach you fitness-app HACKS as workarounds – sure. Or I could just go completely selfish and self-serving while doing you a huge justice – and tell you to become a student of Lifestyle 180. Then you won’t have to “hack” your way to a leaner you. In 1999, when I first created my own tracker, just one facet of all we provide our students, I had already thought of these problems discussed in this article, and so they just don’t exist at LLU.

Wait! I have a new slogan! Instead of “Evidence-based lifestyle education for permanent weight control” I can just say “LLU – No hacking required!”