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Why does my weight go down, but fat percent go up?

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I'm a little confused with the FitBit weight tracking. I have the Aria scale that syncs with the FitBit. I have lost 3.7 pounds since getting the FitBit, but my fat % has gone from 29.3% to 33% in that same timeframe. I am in the goal range of Calories In vs Calories Out on a daily basis mostly. I work out at least 30-40 minutes daily and pay close attention to what I eat.

 

Can anyone give me some insight as to why this may be happening? 

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@worengo I understand how seeing an increase in body fat while you are losing weight can be confusing and frustrating. Here's some insight what's likely happening:

 

Body fat percentage is calculated as fat mass divided by total mass, so if you noticeably lower your total mass, while the fat mass remains the same, your body fat percentage will increase. Even if fat mass is indeed decreasing, total mass is decreasing more quickly, resulting in an increase of body fat percentage.

 

If you continue to weigh yourself daily, you'll probably see that your body fat percent goes down on days when your weight fluctuates up, since you're retaining more water those days, and the total mass has increased. Similarly, on days when your weight fluctuates down, the body fat percent goes up because you're retaining less water, and your total mass is lesser.

 

In short, fat mass decreases more slowly than other types of mass in your body, which may result in a higher body fat percentage. I hope that clarifies what you're seeing! On a longer timeframe, you should see both of these values start to decrease.

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I'm guessing that you bought your Aria as part of a plan to start losing weight, not to better track weight loss that is ongoing. It is common that when you start losing weight, you lose water weight first which results in an increase in body fat percentage. Also, I don't know about you, but my weight can cycle by 4 pounds from day to day (particularly if I weigh myself at different times of day or am a little dehydrated). That's not my usual thing, but it happens often enough to be unremarkable, I need to watch the graph's general trend, not day to day.

 

Finally, if you aren't eating enough, your body will feed itself off your muscles - not burn fat, which decreases muscle (lean body mass) and causes your percent body fat to go up.

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The scales for BF% are not as accurate as you think.

 

The best ones, with you presenting the correct hydrated body, can be upwards of 5% accurate.

Most are closer to 10%, and if you are doing it after a workout day or more or less hydrated than normal, you are making it worse.

 

So the 5 and even the 10% level of accuracy has both of your measurements in there.

 

The are really only good for giving a direction in fat loss over a long period of time, month or more. Not frequent measurements having individual meaning.

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I actually purchased the FitBit items to help me continue to lose weight. I was on weight watchers for about 3 years and in that time frame went from 199.8 to my current weight of 153.3 ( including having a baby in between that three years). I found that my weight loss was dwindling, so I thought the close relation of calories in vs calories out that FitBit provides might show me additional results, which it has. This body fat this is messing with me though. LOL
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As mentioned, body fat scales are not always as accurate as people expect. They are very responsive to variations in hydration. Though, perhaps technically retained fluid weight is lean mass. I was surprised that mine seemed more accurate than I expected when I had the opportunity to do a bod pod test (the result was quite similar to my Tanata scale that morning). For comparison, it helps to try to weight around the same time of day under the same conditions. I would in the morning after using the bathroom. My bf percent comes out the highest this time of day--likely due to dehydration. If I drink a pint of water and re-weight the bf percent will be lower. Really I would use it more for trends and progress and not take the number as fact. Saying that, it is possible and actually common to lose lean mass with weight loss and to end up with a higher body fat percentage. There are things that can be done to diminish this. Common guidelines include regular strength training, avoiding very low calorie diets (unless you have a medical reason more compelling than preserving lean mass), and eating enough protein. But if you are doing everything right, it is probably just that you are retaining less fluid weight.

Sam | USA

Fitbit One, Macintosh, IOS

Accepting solutions is your way of passing your solution onto others and improving everybody’s Fitbit experience.

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@worengo I understand how seeing an increase in body fat while you are losing weight can be confusing and frustrating. Here's some insight what's likely happening:

 

Body fat percentage is calculated as fat mass divided by total mass, so if you noticeably lower your total mass, while the fat mass remains the same, your body fat percentage will increase. Even if fat mass is indeed decreasing, total mass is decreasing more quickly, resulting in an increase of body fat percentage.

 

If you continue to weigh yourself daily, you'll probably see that your body fat percent goes down on days when your weight fluctuates up, since you're retaining more water those days, and the total mass has increased. Similarly, on days when your weight fluctuates down, the body fat percent goes up because you're retaining less water, and your total mass is lesser.

 

In short, fat mass decreases more slowly than other types of mass in your body, which may result in a higher body fat percentage. I hope that clarifies what you're seeing! On a longer timeframe, you should see both of these values start to decrease.

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30-40 minutes a day isn't enough. It's best to look at your Fitbit Mobile and beat all the graph goals.

The top most you want to beat on your chart is Calories. You need to reach your Calories Goal to win body fat burning. My goal per day is 3,500 calories to burn. The higher you burn, the better your fat percentage will be. Mimimize sitting and do more walking. Hit the elliptical on HR Interval Training whenever you can.

 

Also check to see what you're eating. Bad foods like sugary foods, carbohydrated foods, fatty foods. They all can reverse your direction. I ate a Red Velvet Cake over the weekend and gained 7% in 3 days. Dropped it in 3 days avoiding them.

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@josephz2va wrote:

 I ate a Red Velvet Cake over the weekend and gained 7% in 3 days. Dropped it in 3 days avoiding them.


You know of course that you didn't gain 7% bodyfat eating even 1 whole cake, in 3 days.

Neither could you have dropped that amount of BF in 3 days.

How many grams of fat in what you ate?

Actually, just pretend everything you ate was turned in to fat somehow and impossible as that is - how much did the total product weigh?

Is that equal to the 7% gain?

 

This proves out how inaccurate the BF scales are.

 

If anything, you gained water weight with the sugar.

 

This is the wedding cake syndrome. The bridal party starved all week to get in to their dresses. They ate 1 piece of cake as extra food, and find a 3-5 lb gain of weight on Sunday. Somehow thinking it's fat, when the piece of cake didn't even weight 1 lb.

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I have to say that Fitbit should be better at explaining this to users. The set up info is so basic and the app doesn't aleays sync. I haven walked 40 km in the last five days and eaten well and hit calorie burn and still weight is sitting the same. I don't know how well spent that money was to be honest.m I appreciate those here who explained that as overall mass goes down the percentages are skewed, certainly makes me feel better 🙂
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@PMac123 wrote:
I have to say that Fitbit should be better at explaining this to users. The set up info is so basic and the app doesn't aleays sync. I haven walked 40 km in the last five days and eaten well and hit calorie burn and still weight is sitting the same. I don't know how well spent that money was to be honest.m I appreciate those here who explained that as overall mass goes down the percentages are skewed, certainly makes me feel better 🙂

Is that amount of walking normal for you - or a big increase over regular daily activity?

 

Is it getting hot where you are at, and/or are you getting hotter from these walks?

 

Also, effect of exercise is NOT weight loss, usually weight gain - good required desired water weight gain for many reasons. Hence the questions above, which is all about blood volume increasing and glucose attached water.

 

Diet is for weight loss, done right hopefully just fat loss and not muscle mass.

So correct logging of all food you eat by weight - not volume.

 

And 5 days is too short, though if you really start eating less than you burn, you'd normally have a big first week water weight drop, which may still be coming.

As a woman whose base energy use changes through the month, and water weight carried - you'll need at least 30 days to discern what may be going on.

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If weight goes down but % body fat increases I took that to mean I wasn't eating enough and my body was harvesting muscle instead of fat from my intense workouts. I have maintained a steaady weight of about 250lbs since January 2016 and seen my % body fat drop from average of 40%+ to the low 20% (maintaining within 2-3% steady in lower 20's). 

 

That's why I got the scale because I think I am replacing fat weight with muscle weight. If one doesn't eat enough to sustain the lean muscle the body will harvest the muscle first resulting in a weight loss but not in a good way because muscle helps keep metabolism up and burn fat. The trick is to eat enough to support the activity that results in a leaner body with denser muscle mass for better oxygen utilization and a healthier body.

 

 This is my take on answering the question but I am no expert just a former Biology major who dropped out in year three and develops web sites for a living. 🙂

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@Crowesam wrote:

If weight goes down but % body fat increases I took that to mean I wasn't eating enough and my body was harvesting muscle instead of fat from my intense workouts. I have maintained a steaady weight of about 250lbs since January 2016 and seen my % body fat drop from average of 40%+ to the low 20% (maintaining within 2-3% steady in lower 20's). 

 

That's why I got the scale because I think I am replacing fat weight with muscle weight. If one doesn't eat enough to sustain the lean muscle the body will harvest the muscle first resulting in a weight loss but not in a good way because muscle helps keep metabolism up and burn fat. The trick is to eat enough to support the activity that results in a leaner body with denser muscle mass for better oxygen utilization and a healthier body.

 

 This is my take on answering the question but I am no expert just a former Biology major who dropped out in year three and develops web sites for a living. 🙂


Muscle is not an easy to use energy source.

 

You'd have to do several things really wrong to obtain that. Like actually starving - not just a diet.

 

While it's true your body breaks down some muscle daily, and those amino acids could be used as energy source if needed (no carbs or fat available - when is that true?), really it's a minor component when you exercise long enough.

 

Hard cardio longer than 60-90 min protein can start becoming about 10% of the energy source, but that's just what was available already, perhaps some more being available from the workout if intense enough.

But if you eat enough protein later - body knows you need that muscle and will  build it back up again - bigger if diet allows.

 

If going off BIA bodyfat scale - inaccuracies is what you are looking at.

Your level of hydration can vary so much, and totally throw it off.

Must have consistent time to get best chance of consistent results.

Morning after rest day eating normal sodium levels, not sore from last workout.

That takes care of the big expected reasons for fluctuating water weight.

 

You are doing recomp if weight hasn't changed but body composition has.

 

And since no deficit, less of a problem anyway.

But that only works with a progressive overload lifting routine.

 

You could accomplish the opposite of what you are doing and lose weight.

Like someone who has decent upper body strength from years of work - gets a desk job and decides to become a long distance runner to compensate and go on a diet to lose some stomach fat he gained.

That upper body muscle is getting broken down eventually anyway - and with no activity now telling the body to keep it, and being in a diet, and with legs wanting more repair - the upper body just isn't built back up again.

For awhile the BIA scale if accurate might show lost weight and no change in LBM, but eventually he'll look like it in the upper body, then eventually the leg muscles don't need more for endurance, so fat and perhaps more upper muscle is lost.

But not because the muscle is used as fuel source - it's just not rebuilt because it's not needed.

Body doesn't like to keep systems that use more energy then it's getting when it's not needed.

 

Shoot - eat low enough and it could start feeling that way about hair and nails and skin - which is why some people start losing that on extreme diets.

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A general thought on the same. Eating less will add to weight loss but it open the gates to gain more fat. When you say workout i am sure you incorporate weight training as well in your schedule. Too much of cardio just creates a calorie deficit in your body. 

Abhijeet Vaishnav-Fitness Consultant
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I am burning about 3-5000+ calories per day and often exceed 1000 calorie deficit on the intake. Trying to get just ten pounds off to start has been a struggle. Adding weight training and cutting back on sugary stuff.
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@Crowesam wrote:
I am burning about 3-5000+ calories per day and often exceed 1000 calorie deficit on the intake. Trying to get just ten pounds off to start has been a struggle. Adding weight training and cutting back on sugary stuff.
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Doing something wrong then unless your food logging is just dishonest and you are actually eating up that deficit - so that is not it I'd warrant.

 

More likely is the stress you are causing your body by either new or increased daily activity totaling that much and eating that much under.

 

Stress like that elevates cortisol, which increases water weight of the non-good kind.

 

May still see measurements change though. And when body comes out of stressful situation - should have that whoosh effect of water loss, showing up the fat loss that is occurring.

 

But that kind of stress also can make the body slow down in general for calorie burn - meaning the Fitbit which is estimating healthy body calorie burn is now not correct on your body's lower calorie burn.

Adaptive thermogenesis - depending on how long in a diet and how much deficit - you can hit the sweet spot of no actual deficit after a while.

 

At that point you can keep eating less and less and eventually you'll lose again - sadly a stressed out body like that generally doesn't make nearly the good improvements to workouts - why increase body's energy needs from improvements when it's already not getting enough causing slow down.

 

Or come out of the diet for a week or two, and then take a reasonable deficit for amount to be lost.

 

if really only 10 lbs to lose - 250 cal deficit is best.

Or alteranate weeks with a 500 cal deficit and then maintenance.

Or every other day 500 cal deficit then maintenance.

 

Many ways to skin a cat when down to last few lbs. Just don't eat it with chocolate.

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@abhi_kv wrote:

A general thought on the same. Eating less will add to weight loss but it open the gates to gain more fat. When you say workout i am sure you incorporate weight training as well in your schedule. Too much of cardio just creates a calorie deficit in your body. 


Just gotta ask how you think eating less will open gates to gain more fat?

 

Because you do need to eat less than you burn to get rid of fat weight.

By a reasonable amount though to make it fat only.

Unreasonable amount to include some muscle mass.

 

And too much cardio doesn't create a deficit - eating too little does.

 

You can train like a triathlete with tons of cardio, eat enough - and have no deficit or weight loss.

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Thanks again for your feedback. I need to get better about tracking my calorie intake. I have been guesstimating it in my head like I do with my checking account  and spending money. This can lead to bouncing checks calorically as easy as it does financially. hahaha

 

So if half of my daily calories come from chocolate and beer that is a bad thing? 😞

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I can only do head food logging when I eat the same thing - which sadly is rather frequently.

 

I'd say dark chocolate and dark ale. Where's that glass clinky emoti when you need it!

 

Ugh, that just sounds gross together. Actually separately too.

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Wow! Thanks so much for this response...I was getting a bit frustrated! Today's body fat % is the same as when I was 7 lbs heavier 😬

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FitBit moderator is correct. Once your body has uses up the glycogen stored in your liver, it looks to your body fat, not muscle, for energy.  Muscle depletion comes when body fat is depleted first.  You have to be truly starved to lose muscle from weight loss.  That said, the first pounds off are, generally, water, so based on the math your lean body mass will go down as a % of your total weight at first, making your body fat a larger %.  It won't last forever; just keep taking good care of yourself.  For a scientific, but easy read, I recommend The Obesity Code, which is filled with great information.  I'd also advise you to look into "intermittent fasting."  I'm on a 16 hours no feed, 8 hour food window program and loving it.  Basically skip breakfast.  Have a couple of cups of coffee to see you through to lunch.  Have a healthy, low carb lunch.  No snacks.  Have your healthy dinner before 8 hours is up.  Then stop eating until lunch the next day.  Remember a lot of the "no eating" period is while you are asleep.  Also, no need to count calories or log food.  You know what's healthful and what's not at this point, I'm sure!  We all do.  Protein - Good.  Natural fat from eggs, meat, poultry, cheese and whole dairy - good.  Complex Carbs - minimize. Sugars, starch, artificial sweeteners, non-complex carbs - Avoid.  Processed foods - Avoid.  Water, coffee, tea, herbal tea, uncarbonated unsweetened beverages all good.  Artificial sweeteners tell your brain you're eating sugar (simplified, but basically true) and out comes all that insulin you want to avoid.  Best of luck and, trust me, "intermittent fasting" is not only not as bad as it sounds, but if you do the 16/8 plan totally do-able... for life.

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