Calorie deficit - conflicting data / recommendations. Any advice?

[themathkid]

Hello. First post on the Fitbit forums here. I'm a 31 year old male, 200 pounds, 170 goal weight. I've been using Fitbit for about 18 months now (Charge 2 + Aria) and I'm a huge fan.

I'm looking for some advice on calorie needs. Here's where I'm at as far as my understanding of energy needs and how it relates to weight loss.

• I understand the concepts of BMR and TEE and have found and tested several online calculators (example: here) to give me an estimate of what I need to be eating.
• I understand the general lifestyle / activity categories that determine "multipliers" to arrive at TEE. (See footnotes here, for example.)
• I understand how cutting calories approximately relates to weight loss (e.g. cut 500 per day to lose 1 lb per week / 1,000 for 2 lbs, etc.).
• I understand that cutting too much (more than 1,000 calorie deficit) is counterproductive to weight loss.
• I've also read there are general guidelines for lower limits for males (e.g. see last sentence of first paragraph here.)
• I understand the limitations of Fitbit's ability to estimate certain data (e.g. miles, calories burned). 

I think I fall somewhere between light and moderate activity level. Averaging the two "maintain" values from the calculator gives (2610 + 2943) / 2 = 2,777 TEE, approximately. However, Fitbit consistently reports 3,200 - 3,400 average daily burn. I've been dieting in the 1,700 - 2,000 intake range (probably averaging on the higher side of that range) and have been doing very well for the last ~7 weeks. This corresponds to roughly to "lose weight" ranges reported from the calculators above - 700 - 1,000 deficit compared to TEE. I don't typically feel hungry - I feel like I eat "enough." I've lost about 11 pounds, but I can't be sure how much of that is "water weight" / beginner's body shock. I would very much like to maintain this rate of progress. 

Given the large disparity, I'm not sure what number I should be using to base my deficit off. Going off Fitbit's reported burn, it'd seem like I'm cutting way too much and setting myself up for the starvation mechanism kicking in / metabolism dropping significantly and putting me in a no-weight-loss rut. Based on the calculators, I seem to be in a decent deficit range. Further, I'm frequently under the 1,800 lower limit suggested in one of the links above. I'm just not sure what to do. 

What are your thoughts on this? Anyone have advice on "trusting" the Fitbit numbers? For those that have had weight loss success, how did you determine an intake level that was right for you? Any input would be much appreciated.

[Esya]

I recommend getting an account with trendweight.com. You can link it to your FitBit account, so you don't have to input anything at all and it is free. It plots your weight over time and then add a trendline. Then based on that data it will tell you how much you are burning more or less than you are eating.

FitBit is known for overestimating calories burned and it depends on the type of tracker you use. You clearly found something that works for you, so keep going with that.

[Dave001]

It seems that your screen name is very appropriate, @themathkid. You love the numbers!

I take a rather different approach. I've based my weight loss/health improvement drive on a very simple premise:

Eat better; move more.

The only thing I measure is my body weight. If it stagnates for a while, I'll eat a little better and move a little more. I don't worry about calories in the slightest. I have no idea how many of them I consume or burn. 

It's working. In a little under 6 months, my shirt size has gone from XXXL to XL! I've changed my belt for a smaller one and can now run ten miles with ease whereas before I struggled to walk a couple of miles. My friends and family have noticed a huge improvement in my physical and mental health. 

As for the all important numbers... I've lost 26.7kg (almost 59lbs).

The take home message is that the principle of calorie deficit is sound, but the way one chooses to employ the principle can be modified to suit. Just find something that works for you.

Good luck! 

[JenniferinFL]

My activity level varies widely. I could end up sitting in meetings all day, or I could end up shelving all day. Very different calorie burn numbers. I don't feel like doing the math on that disparity everyday. 

Instead, I eat at a 1000 calorie deficit according to my Fitbit Blaze and lose about 1.5 lbs per week or thereabouts, so more like a 750 calorie deficit.  

Because of the over count, I would pick one level up from how you actually want to lose. If you want to lose at a rate of a lb a week, then pick 750 calorie daily deficit instead of 500 and then just eat what Fitbit says you can eat. 

Of course, if you are pretty stable with your activity, then it could make sense to just keep doing the math. My activity fluctuates too much. 

[emili]

I am a huge fitbit fan obviously.. huge. But, the majority of my weight I lost long before I got a fitbit by drastically changing how I ate and how much I moved. I didn't count calories or track my activity, I just ate really lean and pushed myself at the gym. I got the fitbit not to lose weight, but and don't laugh, because I wanted to see how many miles I would walk in Disney. I read an article that said some people walk up to ten miles per day. That sounded insane to me so I got the Charge HR to see for myself. And I was hooked. I believed the calories it said I was burning. I became addicted to weighing and measuring food. I knew how much I need per day because I had already tested it with losing weight and I ended up dropping another 8 pounds. I have used my pal to keep it off. I have since had several of them and currently in a love affair with the Alta HR, after an agonizing break up with the Charge 2. Don't overthink it. You will make yourself crazy. Stick to the basics of eating less moving more- in other words, more calories out than in and you will be OK. Good luck and enjoy the adventure!