How much fat can we really metabolize per week?

Behavior_Modification
Behavior_Modification Posts: 24,482 Member
edited September 21 in Health and Weight Loss
How much fat can we really metabolize per week?

I'd like to open this topic for discussion because I'm very interested to hear what other people have to say on the subject. In the past 5 months I've read 20+ books about healthy eating, healthy lifestyle changes, overcoming overeating and binge eating and anything health/weight loss related I can get my hands on and find interesting. Something I've read recently really stuck with me and I've been thinking about it a lot, actually I can't seem to get it off my mind. So, let's talk about it.

According to what I've read, the human body cannot metabolize more than 2lbs of FAT per week.

According to my trainer, you can metabolize up to 1% of your body weight per week (so if you weigh 300 lbs like I did, it would be 3lbs per week max)

Up until February 2010, I also did not know that when a person loses weight, they lose a combination of fat, muscle, and water weight. Muscle? Whaaaaaat? I don't want to lose my precious muscle that I've been working so hard to build. My personal trainer measures my percentage of body fat and lean muscle mass every time I get an assessment and the fat to muscle ratio has been a hard concept for me to grasp. I have been working my butt off strength training 3X per week for almost 6 months now and I've still managed to LOSE 4lbs of lean muscle mass (lean muscle mass is everything EXCEPT fat, like muscle, bones, tissues, water, organs). Out of the 38lbs that I've lost so far, only 34 of those are actual FAT. The trainer tells me that it is muscle tissue that I'm not using or something like that. Like I said, it has been a difficult concept for me to grasp and I'm still not entirely sure I get it.

I see people on this site all the time who had started out at weights similar to mine and have lost 2X as much as I have in the same amount of time. I can't help but get jealous. But when I talk to my trainer about these statistics, they assure me that I'm doing it the right way so that I'm losing as little precious lean muscle mass as possible and that those people who are losing more than 1 percent of their body weight per week (and especially if they aren't strength training) are actually losing more than just fat. And every time I tried to lose weight in the past I was losing precious muscle also and so my metabolism has progressively gotten slower and slower throughout the years.

I get concerned when I see posts about people losing weight so quickly and posts like "Yeah, I lost 5lbs this week". Well did you actually lose 5lbs of fat? Because you don't want to be happy about losing muscle weight and water weight loss is only temporary.

So, my MFP friends.....what do you think about all this?

Replies

  • Amber030583
    Amber030583 Posts: 490 Member
    Thank you for this post! I did not know this information. Really good to know. :)
  • balfonso
    balfonso Posts: 370 Member
    I was just reading fat burning zones and the science behind it.

    http://www.brianmac.co.uk/fatburn.htm
  • danibabs
    danibabs Posts: 298 Member
    Nice post!! Thanks for all the information, it's definitely very interesting. I have a question though. How does one go about measuring one's body fat?
  • bekylouisex3
    bekylouisex3 Posts: 242 Member
    Thanks for posting this, it has really opened my eyes :noway: I will remember this for the future :wink:
  • erickirb
    erickirb Posts: 12,294 Member
    It is extremely hard to loose weight and not loose muscle at the same time, as generally you need to be in a caloric surplus to build muscle. Even body builders loose muscle when dieting for competition. Mind you they go from close to 10% body fat down below 5%, but loose much more weight than just the 5% body fat lost.
  • TheKitsune6
    TheKitsune6 Posts: 5,798 Member
    This is all really good information - don't forget though that it also depends on what you put into your body that affects what is being burned. Part of the benefit of the Atkins diet is that because there's so much protein and so little carbs the muscles don't break down quite as much, even if there's no exercise (my father and grandmother had to go on Atkins for health reasons).

    Of course we'd also have to consider that at first it's not all bad to lose those extra few pounds of water weight. A lot of time water is being retained at excess amounts because of extra sodium, sugar, alcohol or other variables that may have been a part of the previous lifestyle. So when people switch to a healthy diet and exercise they lose a significant amount of weight in the first couple weeks and then it balances out (if the weight loss is being managed properly).
  • AmyLynn4321
    AmyLynn4321 Posts: 30 Member
    I think that is why mfp is set to let you only loose no more than 2 lbs a week. any more than that isn't healthy. I don't think there is anything wrong w/ losing water weight - when it's like at the begining of your program or maybe after a plateau or after tom. You retain water when you eat lots of sodium and on tom and your body is flushing it out. But yeah I had a week when I didn't do as well and i should have and was too busy to work out and I still lost almost 2 lbs and i KNEW that wasn't good!
    I don't completely understand it but I agree w/ the principle behind all of it - cause I've seen it in my self and others.
  • MsElphaba
    MsElphaba Posts: 432 Member
    Without getting too scientific and just applying some common sense (mine, so take that with a grain of salt ;) ) I would think that losing a little muscle isn't necessarily a bad thing, because if you are losing weight, you are getting smaller and you don't need all that muscle around to support you.

    As far as how fast you burn off weight, I personally think 1-2 pounds a week is optimal for long term results. I really would like to see updates on some of the non-winning Biggest Loser contestants to see if they were able to keep the weight off after the show. They just seem to lose such incredible amounts of weight in a short period of time.

    L
  • Behavior_Modification
    Behavior_Modification Posts: 24,482 Member
    How does one go about measuring one's body fat?

    They weigh me, measure me, pinch me, and pop all those stats into some formula or something, not really sure exactly. But this way is more accurate than the regular BMI calculators. The "pinch" test is where they basically are measuring my fat rolls.

    One very interesting thing I learned about fat is that it can sometimes be mistaken for muscle. Old fat gets hard, so when they first pinched me, some of what they thought was muscle was actually fat that had gotten so hard it was no longer squishy and so they could not get a good pinch from it. Ever touch an old man's gut? Chances are it's not squishy, and the bottom layers of my fat weren't squishy either. So watch out for that because it can hinder accurate statistical results as well.
  • cmw72
    cmw72 Posts: 390 Member
    It turns out there a maximum value that the body can metabolize from fat per day.

    This article by Lyle McDonald explains it pretty well:
    http://www.mindandmuscle.net/articles/lyle_mcdonald/maximum_fatloss

    From the article:
    Based on a somewhat simplified analysis of what data exists (including the seminal Minnesota semi-starvation experiment), they conclude that the maximal rate at which fat stores can provide energy to the body is 290 +- 25 kj/kg which is approximately 31 kcal/lb of fat per day.
    Say we have a 180 lb male at 15% bodyfat. He has 27 lbs. of fat, and his maintenance calorie intake is 15 cal/lb or 2700 calories. With 27 lbs. of fat, he should be able to sustain a caloric deficit, from diet alone, of 27 lbs. fat * 31 cal/lb = 837 calories/day. So he could reduce his calories to 1863 (ha! 10 cal/lb) and shouldn’t lose any LBM at that level of intake. He should get a weekly fat loss of just over 1.5 lbs./week.

    So, it's quite possible for a seriously obese individual to lose a significant amount of fat per week. For somebody who has significantly less body fat, it would be much more difficult, if not impossible (mathematically).
  • canstey
    canstey Posts: 118
    First you lose a combination of fat and LBM (lean body mass, which includes but is not limited to muscle) at approximately a 75% to 25% ratio +- 5%. There is connective tissue and other tissue in LBM. So when you lose LBM it is not 100% the muscle on your biceps, legs, or where ever else you are concerned about strength. You will need to lose some LBM because all of it needed at your maximum weight isn't necessary as your body gets smaller. Also your metabolism, really we are talking strictly about BMR here, is going to go down as you lose weight because you are not working as hard to move your body around and there is some additional energy required to maintain larger fat reserves over smaller ones.

    All the ideas, recommendations, and their ilk to "maximize fat loss" or "retain muscle mass" during weight loss are either hyped way beyond real world results for 99% of healthy people or are flat out false. Create a reasonable calorie deficit to lose weight and be able to stick with it over the long haul. Exercise to improve fitness and don't waste your time with the nuances that may or may not be true and generally account for at most a few percent of the end results.
  • bellanean
    bellanean Posts: 220
    Sounds like you have a great trainer! Keep up the great work :-) You dont want to lose muscle!
  • sunshine79
    sunshine79 Posts: 758 Member
    Your personal trainer is exactly right. I too have become really interested in the whole science of weight/fat loss, nutrition etc and I read Burn the Fat Feed the Muscle by Tom Ventuto. (don't worry I'm not a sales person trying to push his book on you lol) and it totally revolutionised my training and eating.

    From what I've understood it's almost impossible to burn fat and gain lean muscle at the same time, the trick is to fuel yourself with the right foods (lean protein) and train correctly so that you burn fat without wasting away muscle tissue. This is also why it is imperative to have weight training as part of your fitness routine.

    Now don't get me wrong, I'm not a 100% all there yet with all of this but just from putting some of his recommendations into place I've managed to reduce my body fat% and increase my muscle mass. (I have them measured regularly):tongue:

    You are right the 'weight' loss is far slower this way but I think it will stay off.

    Keep doing what you're doing. You're on the right track :glasses:
  • KatWood
    KatWood Posts: 1,135 Member
    Very intersting! There are also devices that will measure your body fat %. A signal is sent through your body and the time it takes to reach the device again is measured and used to determine your body composition fat/water/muscle. I think the idea is that due to the different in density the time it takes to pass through the three different materials is different.
  • TropicalKitty
    TropicalKitty Posts: 2,298 Member
    How does one go about measuring one's body fat?

    They weigh me, measure me, pinch me, and pop all those stats into some formula or something, not really sure exactly. But this way is more accurate than the regular BMI calculators. The "pinch" test is where they basically are measuring my fat rolls.

    One very interesting thing I learned about fat is that it can sometimes be mistaken for muscle. Old fat gets hard, so when they first pinched me, some of what they thought was muscle was actually fat that had gotten so hard it was no longer squishy and so they could not get a good pinch from it. Ever touch an old man's gut? Chances are it's not squishy, and the bottom layers of my fat weren't squishy either. So watch out for that because it can hinder accurate statistical results as well.

    You can also get a scale or the handheld resistance monitors that measure it. I've also had it measured on me with some light device, but I can't remember what it's called. The scale with the bf% option in it is easy to get, though.

    Edit: Here's one: http://www.tanita.com/en/body-water-monitors-fat/
  • xarra
    xarra Posts: 128 Member
    I've lost a stone (14lb) in 3 weeks. I've not got much muscle mass to lose, ad lots of flab...
  • rose1617
    rose1617 Posts: 469 Member
    How does one go about measuring one's body fat?

    They weigh me, measure me, pinch me, and pop all those stats into some formula or something, not really sure exactly. But this way is more accurate than the regular BMI calculators. The "pinch" test is where they basically are measuring my fat rolls.

    One very interesting thing I learned about fat is that it can sometimes be mistaken for muscle. Old fat gets hard, so when they first pinched me, some of what they thought was muscle was actually fat that had gotten so hard it was no longer squishy and so they could not get a good pinch from it. Ever touch an old man's gut? Chances are it's not squishy, and the bottom layers of my fat weren't squishy either. So watch out for that because it can hinder accurate statistical results as well.

    You can also get a scale or the handheld resistance monitors that measure it. I've also had it measured on me with some light device, but I can't remember what it's called. The scale with the bf% option in it is easy to get, though.

    Edit: Here's one: http://www.tanita.com/en/body-water-monitors-fat/
    I use one of those scales.
    It says I have about 30-31% body fat (it varies between the two).
    Then I did both a calipers and a measurements body fat test and they both read 21%.
    Me thinks something's wrong here. The scales aren't accurate is all. Although I'd rather it tell me I have more BF than less and keep me working to get it off. :)
  • TropicalKitty
    TropicalKitty Posts: 2,298 Member
    How does one go about measuring one's body fat?

    They weigh me, measure me, pinch me, and pop all those stats into some formula or something, not really sure exactly. But this way is more accurate than the regular BMI calculators. The "pinch" test is where they basically are measuring my fat rolls.

    One very interesting thing I learned about fat is that it can sometimes be mistaken for muscle. Old fat gets hard, so when they first pinched me, some of what they thought was muscle was actually fat that had gotten so hard it was no longer squishy and so they could not get a good pinch from it. Ever touch an old man's gut? Chances are it's not squishy, and the bottom layers of my fat weren't squishy either. So watch out for that because it can hinder accurate statistical results as well.

    You can also get a scale or the handheld resistance monitors that measure it. I've also had it measured on me with some light device, but I can't remember what it's called. The scale with the bf% option in it is easy to get, though.

    Edit: Here's one: http://www.tanita.com/en/body-water-monitors-fat/
    I use one of those scales.
    It says I have about 30-31% body fat (it varies between the two).
    Then I did both a calipers and a measurements body fat test and they both read 21%.
    Me thinks something's wrong here. The scales aren't accurate is all. Although I'd rather it tell me I have more BF than less and keep me working to get it off. :)

    The science I've seen for the leg-to-leg impedance is very accurate - matches up with DEXA and the water body fat measuring.

    I've seen that the calipers are some of the least reliable versions. (And Diane gave a good explanation as to why)
  • rose1617
    rose1617 Posts: 469 Member
    How does one go about measuring one's body fat?

    They weigh me, measure me, pinch me, and pop all those stats into some formula or something, not really sure exactly. But this way is more accurate than the regular BMI calculators. The "pinch" test is where they basically are measuring my fat rolls.

    One very interesting thing I learned about fat is that it can sometimes be mistaken for muscle. Old fat gets hard, so when they first pinched me, some of what they thought was muscle was actually fat that had gotten so hard it was no longer squishy and so they could not get a good pinch from it. Ever touch an old man's gut? Chances are it's not squishy, and the bottom layers of my fat weren't squishy either. So watch out for that because it can hinder accurate statistical results as well.

    You can also get a scale or the handheld resistance monitors that measure it. I've also had it measured on me with some light device, but I can't remember what it's called. The scale with the bf% option in it is easy to get, though.

    Edit: Here's one: http://www.tanita.com/en/body-water-monitors-fat/
    I use one of those scales.
    It says I have about 30-31% body fat (it varies between the two).
    Then I did both a calipers and a measurements body fat test and they both read 21%.
    Me thinks something's wrong here. The scales aren't accurate is all. Although I'd rather it tell me I have more BF than less and keep me working to get it off. :)

    The science I've seen for the leg-to-leg impedance is very accurate - matches up with DEXA and the water body fat measuring.

    I've seen that the calipers are some of the least reliable versions. (And Diane gave a good explanation as to why)
    Maybe it's just me, but 10% difference seems highly inaccurate. I have a dunk tank test coming up in September. I'll let you know then if the calipers/measurements are closer or if the scale is. But knowing my measurements and other pertinent info, 31% is way off. 21-23% (the error margin) is much more likely.
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