Ok so I've been doin IP about 4 months now. I have lost a total of 65lb. when I started I was 321lb with 49.6 percent body fat.
Now at 256lb I am 46.8 percent fat.
So yes I have lost 3 percent fat. But for some reason my last few weigh in it has been my lean mass going down (currently 135lb) and my fat going up! I totally get it one goes down and the other stays relatively the same but to be up by 0.6 pecernt this week!!!
Anyone else have this issue

Are you getting these calculations from a BCA?

The one thing I will say to this is that those scales which "measure" body fat by standing on them....are not always accurate. The only TRULY accurate way to measure BF% is via a DEXA scan or water displacement test. If someone is VERY skilled in using fat calipers, they could also get a good reading...but you have to be very good at it...and many people (including many doctors) are not.

Your lean mass will periodically go down as you lose weight. The smaller you are, the less connective tissue you need to hold everything together, connective tissue was necessary to keep all that fat in place!

And you are talking in PERCENTAGES. 0.6 percent of 100lbs and 0.6 percent of 80 lbs are two different numbers. So yes, it probably makes perfect sense that your WEIGHT has gone down but your fat % has not changed or gone up, because it is being calculated against a smaller number than what you started with.


The point is, don't get too attached to those percentages. They aren't the most accurate measurement, and the MOST important measurements are your weight and your inches. THAT is where you will be able to tell that the diet is working for you.

I'll agree with the comments here about lean mass measurements being fallible, for starters. I get DXA scans done every 3-4 months for that reason—because I want accurate data.

However, it may very well be true you're losing more lean mass than before, because you've been losing quickly and because fat will drop away more easily at the get go than it will as time goes on.

My understanding is that IP is a very effective diet for losing large amounts of weight in a relatively small amount of time in a healthy way and under doctor supervision. I do not know much more about the diet than that, but what I can tell you is that losing weight quickly absolutely will mean you will lose lean mass, especially if you are female.

As for going "up" fat percent... if you lose more lean than fat (relative to your body composition), your body fat percentage will rise. It does NOT mean you aren't losing fat at all. Most likely you are still losing fat, but at the moment your body is finding it easier to burn the muscle off. Perhaps your body doesn't feel like it needs the muscle for some reason.

Can you describe what kind of exercise you're doing, if any?

As a general rule, strength exercises burn fat, and cardio exercises burn lean mass in the long run (although in the short term cardio is fantastic for burning fat and using up the day's calories, and its effect on lean mass isn't a bad thing, it's a practical thing).

If you want to build (or stop from losing so much) lean mass, the general guiselines are to do more strength exercises (squats are awesome), eat more protein, and lose weight slower. Any one of those would be helpful, so I'd suggest talking to your doctor about the best way for you to work one or more of those into your plan.

Crystalian,

Agreeing with Scorbett, the body comp scales are best at showing change over time. These scales run a slight current through a person to measure impedence, and then do a computation. They are not actually "scanning" us. The impedence can be affected by how hydrated you are, and also even by whether you have pumiced your feet recently or not. So, just note change over time. To me, the change that is most important is not "lean mass percentage" but instead are all the masses measured in pounds, plus the body fat percentage.

Typically, the "lean mass" includes water mass. On the scale at my clinic water mass is called TBW. The water mass will reduce over time as you lose fat mass because the fat is bound to some water. I have subtracted my water mass from my lean mass to get a true lean mass. My "true lean mass" is the same now as it was at my initial weigh in at 50 pounds heavier.

I hope that helps.

If you use a bathroom scale that measures body fat, you need to make sure that your feet are slightly damp. This reduces the resistance and helps the electrical current assess impedence so you get a more accurate reading.

However, as the previous responders mention, it is FAR from an accurate figure. The good news is that it will give you a general trend to track.

The other interesting fact is that the density of fat can also affect the reading. If you have very dense fat (ie small fat cells) it can be misread as muscle.

murrcat, I'm wondering how you go about this. It would be helpful to me, as I gained lean mass at my last DXA scan but it was also just before the start of my cycle and I know I was retaining water because the scale was up and wasn't budging for a few days. The DXA does show fluid retention in its lean mass calculations (although it's a whole lot more accurate than the scales and the pincers).

Do you simply calculate based on your weight fluctuations? Or do you have another way of figuring this out?

I am not on IP.

But I am baffled.

Unless you guys are weight training I don't see why anyone would measure lean (muscle) mass on a diet. You are going to lose both lean mass and fat mass dieting unless you start lifting some weights and even then you will probably still lose both. Yes, a little bit of protein might help retain the lean but it won't be going up any time soon without some serious bar bending.

Just measure mass and hope that you've pooped, pee'd and aren't retaining much water that day.

Hi Faiora,

My clinic uses the Tanita BCA SC 331s. It is a fancy version of the home BCAs and gives more metrics and a printout. Again the caveat of the BCAs--it is a calculation and not fully accurate and more useful for showing trends over time.

This BCA gives fat mass, muscle mass ( which actually includes water so it is lean mass), TBW (or total body water) and bone mass, all measured in pounds. If I take the "lean mass" and subtract total body water from it, this gives what I personally call "true lean mass". My coach (new coach I am one of her first clients and she did not lose weight on the program) did not understand that water would be lost along with fat, and she kept hassling me about my "lean mass" going down and I let her know this was water not muscle, which is why I bothered to calculate this. I believe there is even a P1 IP video that addresses the confusion over this. At any rate, my "true lean mass" is the same now as it was six months/ fifty pounds ago.

I have never had a DXA scan, so I don't know all the metrics it is giving you.

What I would recommend though with all of this, is to just watch trends, and make sure the inches are coming off. The reduction in inches, and ultimately the reduction in pounds are the convincing signs that change is happening.

First, what you've said about lean mass not increasing without working out is untrue in certain circumstances.

When we gain weight, we are lifting it everywhere we go and we gain lean mass as a result. But it can take a while to catch up. So for example, even though my husband and I are both losing weight, we are still carrying around enough weight that our bodies are trying to add lean mass to help us move ourselves around all the time. Over the past 3 months between DXA scans, my husband gained 1.8 lbs of lean mass (I believe margin of error on the machine is about 100g, so it's possible the number is off up to 200g/0.44 lb between two scans). I appear to have gained 2.8 lbs of lean mass, but I have a predictable cycle of water retention that accounts for it, and it's less likely my husband has water retention to consider, with his much steadier system.

Everyone (or nearly everyone) does things throughout the day that count as strength exercises. Getting up from a chair, for example, or leaning over to look in the fridge. When you're heavy, you can gain lean mass from these small things just because you're heavy. When you're light, that's when it becomes more difficult and you have to work harder for the returns.

But lean mass gains aren't my personal reason for measuring my lean mass regularly. I have three identifiable reasons:

1) The scans keep me accountable and help encourage me. This is primary. I have a regular appointment which makes me take a look at everything I'm doing, and I can see exactly how the choices I've made affect my body. For instance, my effort to eat more protein, despite that I've only managed to bump my intake from 15 to 22% (with a goal of 30%) has resulted in no loss of lean mass while losing fat. And my husband's intake of vitamin D (even though he forgets some/many days) has increased his bone mineral density out of the caution range. This kind of information encourages us both to try even harder, because we can see that even our minimal efforts have made a difference. And of course, the accountability comes from having to look at myself every 3-4 months, and having the opportunity to get back on track. There are many ways to do this, but this one works for me.

2) I want to know how many calories I should be eating. The machine calculates my lean mass and tells me, based on that, what my BMR is and how many calories I would need to eat to maintain my current weight, based on my activity level. I didn't have to adjust my calories after this last DXA scan because I didn't lose any lean mass. If I had lost 12 lbs of lean mass along with the 12 lbs of fat I lost, I would have to take my calories down more to avoid a plateau.

3) I want to know what the best goal weight is for me. I have a lot of difficulty setting goals for a certain target weight because the BMI ranges don't reflect my healthy body weight well, and I don't know how my body will change as I lose weight. 180 is supposed to be overweight for my height, but when I weighed 180 I was lean and fit and obviously not overweight. I expect to start losing lean mass eventually as I lose weight (I hope so, since otherwise 180 would be far, far too low a weight for me) but I don't know when that will start happening. In the meantime I'm eating protein to keep up my lean mass and going slowly, because I want maintenance to be as easy as possible. But there may come a point when I should change my plans and the more data I have, the better.

This fully explains it. The DXA does not give a measurement for Total Body Water (TBW) so I am unable to calculate how much of the lean mass is water. However, I think at least some of the water mass is excluded from the DXA scan results because the DXA usually tells me a lower total body weight than my scale gives me. Of course, my scale is more likely to be inaccurate.

I suppose I'll just take the results for what they are, and follow along. It doesn't make much difference if my 2.8 lb lean mass gain over the past 3 months wasn't real, because it's so minimal that it's not going to affect any of my goals.