Paying attention to numbers has never been my specialty. (Hence why I chose journalism, rather than finance, as a career.) That preference applies to my eating and exercise habits too. While I generally know which foods are healthy and I enjoy challenging workouts, I like to rely on my body—and taste buds—as my guide, instead of counting calories or strapping on a heart-rate monitor.

But a couple months ago, I noticed my energy flagging and the scale creeping up. Realizing something was off, I consulted my doctor. He found some nutritional deficiencies, suggested supplements, and told me to track exactly what I’m eating. So I fired up the (rarely used) MyFitnessPal app on my iPhone and put in the calorie and macronutrient settings my M.D. recommended. I also bought a Fitbit Alta HR to take a closer look at my activity level, heart rate, and sleep habits.

Honestly, the thought of converting my exercise and eating patterns into statistics, percentages, and pie charts was a little intimidating. There's no wiggle room with numbers. They don’t sugarcoat facts or justify decisions, like my brain tends to do with an order of fries or a third glass of wine. And while several studies show that food journaling can be an effective way to lose weight, other research finds it can be inaccurate and too much effort to sustain in the long run.

Despite these hesitations, I committed to recording my routines for one month (and set notifications on my phone to remind me to do so). Here’s what I learned when I tracked what I ate, how much I moved, and how well I slept for 30 days.

1. Calories add up (even when I'm eating "healthy").

On the first day I reached my calorie goal as I finished my afternoon snack (whoops!). It’s probably no surprise to anyone who’s ever kept a food diary, but I quickly learned I was consuming more calories, carbs, and fats—and less protein—than I should be.

MyFitnessPal I was shocked to see how quickly all the “healthy” toppings on my salad added up! The “good” fats and nutrient-dense “superfoods” I'd been including in my diet—from the almond butter I spread on whole-grain toast, to the olive oil, half an avocado, and pumpkin seeds on my salad at lunch, to salmon at dinner—were adding up... way up. These “healthy” foods alone equal more than 800 calories and 67.5 grams of fat—more than half my daily calorie goal and past the limit of my daily fat intake. (According to the USDA, up to 35 percent of your calories should come from fat, so if you're eating 1,500 calories per day, that's 58 grams of fat, max.)

This isn’t to say that mono- and polyunsaturated fats aren’t good for you; they benefit your heart and brain and can help lower cholesterol. But an excess of anything can contribute to weight gain. I may have felt virtuous about my healthier choices (those salad toppings sure beat cheddar cheese and bacon), but I wasn't taking into account the amount of calories they contain.

Within a week of tracking, I started to reevaluate my choices, increasing my intake of lean proteins (chicken, protein powder, and beans), veggies, and whole grains to even out my macronutrient balance. This wasn’t easy, but it was eye-opening to realize that even the healthiest foods can pack (a lot) of calories.

2. I wasn’t moving as much as I used to.

Last fall I moved from New York City, where everyone walks, to Atlanta, where everyone drives, which took a major toll on my daily step count. Plus, I started working from home, so I wasn’t even walking to and from an office building every day.

Fitbit Steps My FitBit made it fun to hit 10,000 steps every day. Those crazy-high counts are from a weekend in NYC! I can’t say for sure this contributed to my weight gain, but I realized I had to be more intentional about fitting in movement if I wanted to hit my 10,000-step goal. Fortunately, it was a pretty fun challenge—and the "celebration" Fitbit threw every time I reached my goal was extra incentive. I started to run errands by foot, walk an extra 15 minutes around the park, and just tried to move more in general.

3. Monitoring your heart rate comes in handy.

Despite years of working out and even a few half-marathons under my belt, I've never paid attention to my heart rate. But when I started seeing it flash on my Fitbit along with my step count, I was intrigued. Using the Karvonen formula, I found out what my heart rate should be when exercising at a moderate (124 to 150 bpm) and vigorous (151 to 178 bpm) intensity. Then I started checking it mid-run or mid-class. (Who would’ve thought hot yoga sends your heart rate soaring?!) It helped me make sure I stayed in that moderate zone on long walks and entered the “vigorous” zone for at least 20 minutes, two times per week, per the ACSM guidelines.

4. I wasn’t sleeping as much as I thought.

This may have been the biggest surprise of all. Most nights I get in bed at 11 p.m., fall asleep by 11:30 or so, and wake up around 8 a.m. That should add up to at least eight hours of sleep, right? Not exactly. Since the Fitbit monitors your heart rate, it can tell which stage of sleep you’re in—light, deep, or REM—as well as how often you wake up during the night.

Fitbit Sleep A typical night’s sleep. Even though I was in bed for eight hours, I slept for only seven. In my first week of tracking, I was shocked to see I logged only six and a half hours of sleep on a night when I was in bed from 11 p.m. to 8 a.m.! Turns out I didn’t actually fall asleep until midnight and woke up several times during the night, so by the time my alarm went off at 7 a.m., I only accumulated six hours of restorative sleep. Personally, I think my body needs at least eight.

As a result, I started making an effort to put down my phone by 10:30 to ensure I get a solid eight hours. I’m getting better, but there are still nights when I get only six or seven—and I can tell the difference in my energy levels without even checking my Fitbit data. On nights I allow plenty of time to clock some solid zzzs, I feel so much more energized.

5. Exercise is not a magic bullet for weight loss.

It’s a truth I’ve heard time and time again, but always tried to ignore: You can’t out-exercise a bad diet. In other words, what you eat matters way more than how many calories you burn or steps you take. Plus, research shows people often overestimate how many calories they burn when working out, so we may eat more than we really need to after a workout.

Tracking my daily stats helped me finally accept this fact. On days I worked out intensely, I definitely ate more and usually went over my calorie (and carb) intake for the day. But on rest days, or when I just went to a gentle yoga class, it was much more manageable to keep my meals in line with my calorie and macronutrient goals, which is the surest way to shed pounds. I still prefer to work out—and get my heart rate up!—more days of the week than not, but now I think twice about treating myself to a big bowl of pasta post-workout.

6. Disconnecting is essential.

Over the last couple years, there’s been a lot of backlash to the self-tracking movement. And I see why. Distilling everything you eat and do into numbers can be exhausting, disheartening, and borderline obsessive. So when I went on vacation for the Fourth of July, I left my Fitbit at home and didn’t open MyFitnessPal once.

Locke Hughes Spending a week without my Fitbit was a nice break. And this hike still counted—even if I didn’t track it! I hiked without tracking how many steps I took or looking at my heart rate. I simply enjoyed the fresh mountain air and let the burn in my legs be all the data I needed. I ate whatever my body felt like eating, fit in lean protein at every meal, and stopped when I felt full—not when I hit my calorie goal for the day. While it was freeing to stop tracking for a week, I do think that 30 days’ worth of data helped me find that delicate balance between eating and doing what I want versus what’s actually healthy for my body. It helped me realize that I don’t need to overdo it—either fitness- or food-wise—to feel good, although I do need to get plenty of sleep! But after a week off, I was ready to get back on track. Maybe one day my body's own signals will be all I need, but for now, my Fitbit’s back on my wrist.

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